electrical handbook
TRANSCRIPT
Ferraz ShawmutBook of
ElectricalInformation
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The Ferraz Shawmut Book of Electrical Information– A Technical Handbook –
For the use of some tables and other information included in thesepages, we express our grateful acknowledgement to:
Aluminum Company of America
Cornell Dubilier Electric Corp.
Garland Manufacturing Company
General Electric Company
Insulate Cable Engineers Association
Institute of Electrical and Electronic Engineers
National Electric Products Corporation
Steel City Electric Corporation
Whitehead Metal Products Company Inc.
NOTE: For all information contained in the rules, permissions, tablesand charts of the National Electrical Code and the Canadian ElectricCode, consult the current edition of that code.
The following are Registered U.S. Trademarks of Ferraz Shawmut andapply to the products described herein.
, Tri-onic� , Amp-Trap� and � Are registered
trademarks of Ferraz Shawmut Inc.
Copyright, 1939, 1942, 1956, 1967, 1971, 1978, 1979, 1981, 1982,1983, 1984, 1985, 1986, 1987, 1988, 1990, 1996.
Ferraz Shawmut Inc.374 Merrimac Street
Newburyport, MA 01950
ISO 9001 Registered
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TABLE OF CONTENTS
Definitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4-17
Skin Effect . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .18
Wire and Data Applications . . . . . . . . . . . . . . . . . . . . . . . . .19-38
Line Current and Voltage Drop . . . . . . . . . . . . . . . . . . . . . . .39-48
Electrical Formulae . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .49-51
Motor Data and Overcurrent Protection . . . . . . . . . . . . . . . .52-63
Capacitors for Power Factor Correction . . . . . . . . . . . . . . . .64-66
Transformer Data & Overcurrent Protection . . . . . . . . . . . . .67-76
Graphic Symbols for Electrical Wiring . . . . . . . . . . . . . . . . .77-78
Annual Operating Costs of Appliances . . . . . . . . . . . . . . . . . . .79
Temperature Comparison - C° and F° . . . . . . . . . . . . . . . . . . . .80
General Conversion Tables - Equivalent Units . . . . . . . . . . .81-82
Weights and Measures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .83
Metric and Decimal Equivalents . . . . . . . . . . . . . . . . . . . . . .84-86
Areas and Circumferences of Circles . . . . . . . . . . . . . . . . . . . .87
Trigonometric Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . .88-90
Weights of Various Substances . . . . . . . . . . . . . . . . . . . . . . . . .91
Physical & Mechanical Properties of Materials . . . . . . . . . . .92-94
Conduit Dimensions and Data . . . . . . . . . . . . . . . . . . . . . . .95-97
Hardness Conversion Table . . . . . . . . . . . . . . . . . . . . . . . . . . .98
Threads, Drill and Sheet Metal Sizes . . . . . . . . . . . . . . . . .99-100
Sheet Metal Gauges . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .101
Pulley and Shafting Data . . . . . . . . . . . . . . . . . . . . . . . . .102-105
Short Circuit Calculations and Data . . . . . . . . . . . . . . . . .106-120
Global Electrical Systems & Fuse Standards . . . . . . . . . . . . . .121
Suggested Fuse Specifications . . . . . . . . . . . . . . . . . . . .122-123
Dimensions of Fuses and Fuseholders . . . . . . . . . . . . . .124-127
Ferraz Shawmut Products . . . . . . . . . . . . . . . . . . . . . . . .128-144
Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .145-147
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ELECTRICAL DEFINITIONS
1. Volt.* The unit of electromotive force, electrical pressure, ordifference of potential. Represented by E or V.
2. Ampere.* The unit of current flow. Represented by I.
3. Ohm.* The unit of electrical resistance. Represented by R.
4. Energy. The capacity for doing work.
5. Power. Rate of work, equals work divided by time.
6. Watt. The unit of electrical power. Represented by P or W.
7. Joule. The unit of work.
8. Kilowatt. One thousand watts. Expressed by kW.
9. Current. The motion of a charge in a conductor.
10. Direct Current. A unidirectional current. Abbreviated DC.
11. Pulsating Current. Direct current which changes regularly inmagnitude.
12. Continuous Current. Steady-state current, AC or DC.
13. Alternating Current. A current which reverses regularly indirection. The term “alternating current,” or AC, refers to acurrent with successive waves of the same shape, areaand period.
14. Cycle. One complete wave of positive and negative values ofan alternating current.
15. Electrical Degree. One 360th part of a cycle.
16. Period. The time required for the current to pass throughone cycle.
17. Frequency. The number of cycles per second. One cycle persecond equals one Hertz (Hz).
*One volt will cause on ampere of current to flow through a resistance of one ohm.
18. Root-Mean Square or Effective Value. The square root ofthe mean of the squares of the instantaneous values for onecomplete cycle. It is usually abbreviated r.m.s. Unless otherwisespecified, the numerical value of an alternating current refers to itsr.m.s. value. The r.m.s. value of a sinusoidal wave is equal to itsmaximum, or peak value, divided by �2.
19. Wave-Form or Wave-Shape. The shape of the curve obtainedwhen the instantaneous values of an alternating current are plottedagainst time in rectangular coordinates. The distance along thetime axis corresponding to one complete cycle of values is usuallytaken as 2� radians, or 360 electrical degrees.
20. Simple Alternating or Sinusoidal Current. Current whosewaveshape is sinusoidal. Alternating current calculations arecommonly based upon the assumption of sinusoidal currents andvoltages.
21. Phase. The factional part of the period of a sinusoidal wave,usually expressed in electrical degrees and referenced to theorigin.
22. Crest Factor. The ratio of the peak or maximum value of awave, to the r.m.s. value. The crest factor of a sine wave is �2.
23. Form Factor. The ratio of the r.m.s. to the average value of aperiodic wave.
*24. Phase Difference: Lead and Lag. The difference in phasebetween two sinusoidal waves having the same period, usuallyexpressed in electrical degrees. The voltage wave if generally takenas the reference, so in an inductive circuit the current lags thevoltage, and in a capacitive circuit the current leads the voltage.Sometimes called the phase angle.
*25. Counter-Clockwise Convention. It is aconvention that in any vector diagram, the leadingvector be drawn counter-clockwise with respectto the lagging vector, as in the accompanyingdiagram, where OI represent the vector of a currentin a simple alternating current circuit, lagging behindthe vector OE or impressed voltage.
* Refers only to cases where the current and voltage are both sinusoidal.
E I
O
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*26. The Active or In-Phase Component of the current in acircuit is that component which is in phase with the voltage acrossthe circuit.
*27. Reactive or Quadrature Component. That component ofthe current which is quadrature, or 90 degrees out of phase, withthe voltage across the circuit.
*28. Reactive Factor. The ratio of the reactive volt-amperes to theapparent power.
*29. Reactive Volt Amperes. The product of the voltage, currentand the sine of the phase difference between them. Expressed invars.
*30. Non-Inductive Load and Inductive Load. A non-inductiveload is a load in which the current is in phase with the voltageacross the load. An inductive load is a load in which the currentlags behind the voltage across the load.
31. Power in an Alternating-Current Circuit. The product of thevoltage, current and the cosine of the phase difference betweenthem. Expressed in watts.
32. Volt Amperes or Apparent Power. The product of the voltageacross a circuit and the current in the circuit. Expressed in VA.
33. Power Factor. The ratio of the power as defined in (31) to thevolt amperes (32). In the case of sinusoidal current and voltage,the power factor is equal to the cosine of their phase angle.
34. Single-Phase. A term characterizing a circuit energized bya single alternating voltage source.
35. Three Phase. A term characterizing a combination of threecircuits energized by alternating voltage sources which differ inphase by one-third of a cycle, 120 degrees.
36. Quarter-Phase or Two-Phase. A term characterizing acombination of two circuits energized by alternating voltage sourceswhich differ in phase by a quarter of a cycle, 90 degrees.
* Refers only to cases in where the current and voltage are both sinusoidal.
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37. Six-Phase. A term characterizing the combination of six circuitsenergized by alternating e.m.f.’s which differ in phase by one-sixthof a cycle; i.e., 60 degrees.
38. Polyphase. A general term applied to any system of morethan a single phase. This term is ordinarily applied to symmetricalsystems.
39. The Load Factor of a Machine, Plant or System. The ratioof the average power to the peak power during a specified periodof time. In each case, the interval of maximum load and the periodover which the average is taken should be definitely specified.The proper interval and period are usually dependent upon localconditions and upon the purpose for which the load factor isto be used.
40. Plant Factor or Plant Capacity. The ratio of the average loadto the rated capacity of the power plant.
41. Demand Factor. The ratio of the maximum demand of anysystem to the total connected load of the system, or of the part ofthe system under consideration.
42. Diversity Factor. The ratio of the sum of the maximum powerdemands of the subdivisions, or parts of a system, to the maxi-mum demand of the whole system or of part of the system underconsideration.
43. Connected Load. The combined continuous rating of all theequipment connected to the system or part of the system underconsideration.
44. Efficiency. The efficiency of an electrical machine or apparatusis the ratio of its useful power output to its total power input.
45. Rating. The rating of an electrical device includes (1) the normalr.m.s. current which it is designed to carry, (2) the normal r.m.s. volt-age of the circuit in which it is intended to operate, (3) the normalfrequency of the current and the interruption (or withstand) rating ofthe device (see 52).
46. Continuous Rating. The maximum constant load that can becarried continuously without exceeding established temperaturerise limitations under prescribed conditions.
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47. Short-Time Rating. The maximum constant load that canbe carried for a specified time without exceeding establishedtemperature rise limitations under prescribed conditions.
48. Ampacity. The current a conductor can carry continuouslywithout exceeding its temperature rating. Ampacity is a function ofcable size, insulation type and the conditions of use.
49. Overcurrent. Any current in excess of conductor ampacity orin excess of equipment continuous current rating.
50. Overload. The operation of conductors or equipment a currentthat will cause damage if allowed to persist.
51. Short Circuit. Excessive current flow caused by insulationbreakdown or wiring error.
52. Interrupting Rating or Capacity. Interrupting (breaking orrupturing) capacity is the highest r.m.s. current at normal voltagewhich a device can interrupt under prescribed conditions.
53 Ambient Temperature. The temperature surrounding anobject under consideration.
ROTATING MACHINES
54. Generator. A machine which converts mechanical power intoelectrical power.
55. Motor. A machine which converts electrical power intomechanical power.
56. Booster. A generator inserted in series in a circuit to add orsubtract from the circuit voltage.
57. Motor-Generator Set. A conversion device consisting of oneor more motors mechanically coupled to one or more generators.
58. Dynamotor. A converter with both motor and generator in onemagnetic field, either with two armatures, or with one armaturehaving two separate windings.
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59. Direct-Current Compensator or Balancer. Comprises twoor more similar direct-current machines (usually with shunt orcompound excitation) directly coupled to each other and connect-ed in series across the outer conductors a multiple-wire system ofdistribution, for the purpose of maintaining the potentials of theintermediate wires of the system, which are connected to thejunction points between the machines.
60. Double-Current Generator. Supplies both direct and alternat-ing currents from the same winding.
61. Converter. A device which changes electrical energy from oneform to another. There are several types of converters:
62. Direct-Current Converter. A device which converts directcurrent to direct current, usually with a change of voltage.
63. Synchronous Converter or Rotary Converter. Converts analternating current to a direct current.
64. Frequency Converter. Converts the power of an alternatingcurrent system form one frequency to one more other frequencies.
65. Rotary Phase Converter. Converts an alternating currentsystem of one or more phases to alternating current system of adifferent number of phases, but of the same frequency.
66. Phase Modifier or Phase Advancer. A machine which suppliesleading or lagging reactive volt amperes to the system to whichit is connected. Phase modifiers may be either synchronous orasynchronous.
67. Synchronous Phase Modifier or Synchronous Condenser.A synchronous motor, running without mechanical load, the fieldexcitation of which may be varied so as to modify the power factorof the system.
68. Alternator. An alternating current generator, either singlephase or polyphase.
69. Inductor Alternator. An alternator in which both field andarmature windings are stationary and in which the voltage is pro-duced by varying the flux linking the armature winding.
70. Synchronous Motor. An alternating current motor whichoperates at the speed of rotation of the magnetic flux.
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71. Induction Motor. An alternating current motor, either single phaseor polyphase, comprising independent primary andsecondary windings, in which the secondary receives powerfrom the primary by electromagnetic induction.
72. Induction Generator. An induction machine, driven abovesynchronous speed, used to convert mechanical power toelectrical power.
73. Unipolar or Acyclic Machine. A direct current machine in whichthe voltage generated in the active conductors maintains the samedirection with respect to those conductors.
74. Constant-Speed Motor. A motor whose speed is either constantor varies little, such as synchronous motors, induction motors with lowslip and ordinary direct-current shunt motors.
75. Multispeed Motor. A motor which can be operated at any of sev-eral distinct speeds, usually by changing the number of poles or num-ber of windings.
76. Adjustable-Speed Motor. A motor whose speed may bevaried gradually over a considerable range, but remains practicallyunaffected by the load.
77. Varying-Speed Motor. A motor whose speed varies with the load,ordinarily decreasing when the load increases.
78. Base Speed of an Adjustable-Speed Motor. That speed of amotor obtained with full field under full load with no resistor in thearmature circuit.
79. Variable Speed Motor. A motor with a positively damped speed-torque characteristic which lends itself to controlled speed applications.
TRANSFORMERS
80. Transformer. A device for transferring energy in an alternating cur-rent system from one circuit to another, consisting of two independentelectric circuits linked by a common magnetic circuit.
81. Potential Transformer. A transformer designed for shuntor parallel connection in its primary circuit, with the ratio oftransformation appearing as a ratio of potential differences.
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82. Current Transformer. A transformer designed for seriesconnection in its primary circuit with the ratio of transformationappearing as a ratio of currents.
83. Instrument Transformer. A transformer (current or poten-tial) suitable for use with measuring instruments; i.e., one in whichthe conditions of the current, voltage and phase angle in the pri-mary circuit are represented with acceptable accuracy in the sec-ondary circuit.
84. Auto-Transformer. A transformer having some of its turnscommon to both primary and secondary circuits.
85. Primary. The windings of a transformer which receive ener-gy from the supply circuit.
86. Secondary. The windings which receive the energy byinduction from the primary.
87. Voltage Ratio. The voltage ratio of a transformer is the ratioof the r.m.s. primary terminal voltage to the r.m.s. secondary cur-rent, under specified conditions of load.
88. Current Ratio. The current ratio of a current transformer isth ratio of r.m.s. primary current to r.m.s. secondary current, underspecified conditions of load.
89. Marked Ratio. The marked ratio of an instrument trans-former is the ratio of the rated primary value to the rated sec-ondary value as stated on the nameplate.
FUSES
90. Fuse. An overcurrent protective device containing a calibrat-ed current-carrying member which melts and opens under speci-fied overcurrent conditions.
91. General Purpose Fuse. A fuse which meets industry stan-dards for overload and short circuit protection as well as physicaldimensions. This fuse type is tested and certified by nationallyrecognized testing laboratories and may be applied in accordancewith the National Electrical Code and the Canadian ElectricalCode to provide main, feeder and branch circuit protection.
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92. Enclosed Cartridge Fuse. A fuse with a tubular body havinga terminal on each end and a current-responsive element (link)inside.
93. Non-Renewable Fuse. An enclosed fuse with a link whichcannot be replaced after operation. This fuse contains an arcquenching filler.
94. Renewable Fuse. An enclosed fuse, the body of which canbe opened and the fusible link replaced for re-sue. This fuseusually does not a have a filler.
95. Time Delay Fuse. A fuse which will carry an overcurrent of aspecified magnitude for a minimum specified time without opening,as defined in the tri-national Fuse Standard 248.
96. Current-Limiting Fuse. A fuse which will limit both themagnitude and duration of current flow under short circuitconditions.
97. UL/CSA Class Fuses. General purpose fuses meeting one ofthe industry standards called “classes.” Fuse classifications H, J,K, L, R, CC, G and T. Qualifying fuses are typically tested andcertified by UL or CSA to tri-national Fuse Standard 248.
98. Rejection Fuse. A current-limiting fuse with high interruptingrating and with unique dimensions or mounting provisions.
99. Bolt-In Fuse. A fuse which is intended to be bolted directly tobus bars, contact pads or fuse blocks.
100. Semiconductor Fuse. An extremely fast-acting fuse intendedfor the protection of power semiconductors. Sometimes referred toas a rectifier fuse.
101. Midget Fuse. A term describing a group of fuses used forsupplementary circuit or component protection, all having dimensionsof 1-1/2” long and 13/32” diameter.
102. Glass Fuses. A loose term describing a group of low voltagefuses, with glass or ceramic bodies, having dimensions smallerthan midget fuses. Also called “miniature” fuses, they are typically1/4” x 1-1/4,” 1/4” x 1,” or 5mm x 20mm. These fuses are used toprotect electronic circuits or components.
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103. Micro Fuses. Term describing the smallest sizes of fuses,usually mounted on, or used to protect, printed circuit boards orsmall electronic components.
104. Special Purpose Fuses. Fuses with special performancecharacteristics or ratings intended to protect equipment orcomponents under specified conditions.
105. Limiter. A special purpose fuse which is intended to provideshort circuit protection only.
106. Welder Protector. A fuse with special characteristics to meetheavy inrush current demands of an electric welder and protectthe welder on short circuits.
107. Cable Protector. A fuse with characteristics designed toprotect cables against fault damage. Cable protectors have uniquemounting and crimping terminals.
108. Low Voltage Fuses. Fuses rated 600 volts and below.
109. Medium voltage Fuses. Fuses rated from 601 volts to34,500 volts.
110. High Voltage Fuses. Fuses rated 34,500 volts and above.
111. Plug Fuse. A “household” type fuse with a threaded basesuch as an Edison-base or Type S tamperproof base. Rated 0-30amperes, 125 volts.
112. Class CC Fuse. A small current-limiting rejection type fusefor control circuits. Rated 0-30 amperes, 600 volts and 200,000amperes interrupting rating.
113. Class G Fuse. A small current-limiting fuse which comes infour sizes 0-15A, 20A, 25-30A and 35-60A which are non-inter-changeable. Rated 480 volts with a 100,000 ampere interruptingrating.
114. Class H Fuse. Any 250 or 600 volt “standard” dimensionfuse, either renewable or non-renewable which has a 10,000ampere interrupting rating.
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115. Class J Fuse. A 600 volt non-interchangeable current-limitingfuse of small, unique dimensions. Available in ratings 0-600amperes with a 200,000 ampere interrupting rating.
116. Class K Fuse. A 250 or 600 volt standard dimension fuse(no rejection feature) with an interrupting rating of 50,000 or100,000 amperes, meeting specific Ip and 12t limits. Availablein ratings 0-600 amperes.
117. Class L Fuse. A 600 volt bolt-in, current-limiting fuse ofunique dimensions. Class L fuses are rated 601-6000 ampereswith a 200,000 ampere interrupting rating.
118. Class R Fuse. A 250 or 600 volt standard dimensions fusewith a 200,000 ampere interrupting rating and a rejection featureon one terminal. They are current-limiting fuses rated 0-600amperes.
119. Class T Fuse. A small, unique dimension current limitingfuse, non-interchangeable with any other fuse. Available in 300volt and 600 volt sizes, rated 0-1200 amperes, with a 200,000ampere interrupting rating.
120. Ampere Rating. The continuous current carrying capability ofa fuse under defined laboratory conditions. The ampere rating ismarked on each fuse. Class L fuses and E-rated fuses may beloaded to 100% of their ampere rating. For all other fuses, continu-ous load current should not exceed 80% of fuse rating.
121. Filler. A non-conductive medium filling the inside of a fuse forquenching electric arcs and absorbing energy produced by ele-ment or link melting during interruption.
122. Fuse Block or Fuse Holder. A device, designed and intend-ed to hold a fuse and provide the means to connect it to the elec-trical circuit. Fuse blocks consist of fuse clips, insulator and termi-nals.
123. Rejection Fuse Block. A fuse block designed to acceptfuses of a specific class.
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124. Fuse Clip. A conductive mechanical device for accepting andsecuring the conductive part of a fuse to an electrical terminal orconnection point.
SWITCHES, CIRCUIT BREAKERSAND AUXILIARY APPARATUS
125. Circuit Breaker. A device designed to open and close a circuitby non-automatic means and to open the circuit automatically ona predetermined overcurrent without injury to itself when properlyapplied within its rating.
126. Air Switch. A switch arranged to interrupt circuits in air.
127. Air Circuit Breaker. A circuit breaker arranged to interruptone or more electric circuits in air.
128. Molded-Case Circuit Breaker. A circuit breaker which isassembled as an integral unit in a supporting and enclosinghousing of molded insulating material.
129. Thermal-Magnetic Circuit Breaker. A circuit breaker whichhas the overcurrent and tripping means of the thermal type, themagnetic type or a combination of both.
130. Fused Circuit Breaker. An integrally fused circuit breakerwhich combines the design and operating features of a circuitbreaker and current-limiting fuse in one package.
131. Oil Switch. A switch arranged to interrupt one or moreelectric circuits in oil.
132. Oil Circuit Breaker. A circuit breaker arranged to interruptone or more electric circuits in oil.
133. Conducting Parts. Those parts designed to carry current orwhich are conductively connected therewith.
134. Contact. The surface common to two conducting parts,united by pressure, for the purpose of carrying current.
135. Grounded Parts. Parts that are intentionally connected toground.
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136. Dust-Proof. Apparatus is designated as dust-proof when soconstructed or protected that the accumulation of dust with or withoutthe device will not interfere with its successful operation.
137. Dust-Tight. Apparatus is designated as dust-tight when soconstructed that the dust will not enter the enclosing case underspecified test conditions.
138. Gas-Proof. Apparatus is designated as gas-proof when soconstructed or protected that the specified gas will not interferewith successful operation.
139. Gas-Tight. Apparatus is designated as gas-tight when soconstructed that the specified gas will into enter the enclosingcase under specified test conditions.
140. Totally Enclosed. Apparatus with an integral enclosure soconstructed that, while not airtight, the enclosed air has no deliberateconnection with external air except for draining and breathing.
141. Moisture-Resisting. Apparatus is designated as moisture-resisting when so constructed or treated that it will not be readilyinjured by moisture.
142. Drip-Proof. Apparatus is designated as drip-proof when it isconstructed so that successful operation is not interfered withwhen falling drops of liquid or solid particles strike or enter theenclosure at an angle of 0 to 15 degrees from vertical.
143. Splash-Proof. An open apparatus in which the ventilationopenings are so constructed that drops of liquid or solid particlescoming toward it at any angle up to 100° downward from verticalcannot enter directly or by running along a surface.
144. Submersible. Apparatus is designated as submersiblewhen so constructed that it operates successfully in water underspecified pressure and time conditions.
145. Sleet-Proof. Apparatus is designated as sleet-proof when soconstructed or protected that the accumulation of sleet will notinterfere with its successful operation.
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146. Contactor. A device for repeatedly establishing or interruptingan electrical circuit under normal conditions. It is usually magneticallyoperated.
147. Electric Controller. A device, or group of devices, whichserves to control, in some manner, the electric power delivered tothe apparatus to which it is connected.
148. Switch. A device for making, breaking, or changing connec-tions in an electric circuit, the operation of which is independent ofthe circuit to which it is connected.
149. Master Switch. A switch which serves to dominate theoperation of contactors, relays and auxiliary devices of an electriccontroller.
150. Control Switch. A manually operated switch for controllingpower operated switches and circuit breakers.
151. Auxiliary Switch. A switch actuated by the main device forsignaling, interlocking, etc.
152. Disconnecting Switch. A switch which is intended to opena circuit only after the load has been removed by some othermeans.
153. Load-Break Switch. A switch which is designed for, andintended to open a circuit which may be under load.
154. Relay. A device which is operative by variation in the conditionsof one electric circuit to effect the operation of other devices in thesame or another electric circuit.
155. Rheostat. An adjustable resistor constructed so that itsresistance may be changed without opening the circuit.
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SKIN EFFECT
Alternating current causes an unequal distribution of current ina wire. The current density decreases toward the center of theconductor so that for large wires the central portion is used asa conductor, thus increasing the resistance of the wire above thatwhich it would for a continuous current.
This is known as “Skin Effect”
The skin effect increases with the frequency and also with thediameter of the wire, in such a way that for the same percentageof increase in the resistance due to skin effect, the product (diam-eter2 x frequency) is constant.
Table A gives skin effect factors for different values of the productof frequency and cross-sectional area. Table B gives skin effectfactors for different frequencies and sizes of wire.
SKIN EFFECT AT 20°C. FOR STRAIGHTCYLINDRICAL CONDUCTORS
B
Copper Wire
Diameter Skin Effectand
AWG
2.00”1.75”1.50”1.25”1.125”1.000”
0.75”0.50”
0000000000
25 Cycle
1.2221.1451.0851.0421.0281.018
1.0061.0011.000
60 Cycle
1.751.561.381.2011.1431.095
1.0311.0071.0041.0031.0021.001
A
Skin Effect Factor
Frequencyx Areain C.M.
10,000,00020,000,00030,000,00040,000,00050,000,00060,000,000
70,000,00080,000,00090,000,000
100,000,000125,000,000150,000,000
175,000,000200,000,000
Copperu = 1.
p = 1.72
1.001.0081.0251.0451.0701.096
1.1261.1581.1951.231.3321.433
1.531.622
Aluminumu = 1.
p = 2.77
1.001.001.0061.0151.0261.04
1.0531.0691.0851.1041.1511.206
1.2661.33
WIRE DATA ANDAPPLICATIONS
Wire GagesThe American Wire Gage (AWG) - once called Browne and Sharpe or B.and S., is used almost exclusively in the U.S. for copper wire. TheBirmingham Wire Gage (B.W.G.) is used for steel wire. In England, copperwire sizes are often specified by the English (or Imperial) Standard WireGage (S.W.G.), sometimes called New British Standard or N.B.S.
AWGThe diameters according to the AWG are defined as follows: The diameterof size #0000 (often written 4/0) is chosen to be 0.4600 inch and that ofsize #36, 0.0050 inch. Intermediate sizes are found by geometric progres-sion. That is, the ratio of one size to that of the next smaller size (largergage number) is:
= 1.122 932
Circular MilAlso called cmil, the circular mil is used to define cross-sectional area ofwires, being a unit of area equal to the area of a circle 1 mil (0.001 in.) indiameter. Such a circle has an area of 0.7854 (or π/4) mil2. Thus, a wire 10mils in diameter has a cross-sectional area of 100 cmils or 78.54 mil2. Akcmil is 1000 cmils (785.4 mil2).
Conductivity of CopperThe conductivity of copper is usually expressed in percent of a standardconductivity based upon the International Annealed Copper Standard ofresistance, which is defined as follows: The resistance of a wire one meterin length and weighting one gram at a temperature of 20° C is 0.15328ohm. Expressed in various units, the International Annealed CopperStandard has the values:
0.15328 ohm (meter, gram) at 20° C875.20 ohms (mile, pound) at 20° C0.017241 ohm (meter, sq. mm) at 20° C0.67879 microhm-inch at 20° C10.371 ohms (mil, foot) at 20° C1.7241 microhm-cm at 20° C
Temperature CoefficientThe D.C. resistance of copper wire increases with increasing temperature inaccordance with the formula:
39
FERRAZ SHAWMUT
19
0.46000.0050
where R t = Resistance at temperature tR o = Resistance at temperature to� = Temp. Coefficient of Resistance
At 20° C. (68° F.) the temperature coefficient of copper with 100% conductivity is0.00393 per degree Centigrade or 0.00218 per degree Fahrenheit. Thetemperature coefficient at another temperature or for copper of any conductivity(e.g., hard drawn wire) may be calculated from the following formula, whichdepends upon the fact that the temperature coefficient is proportional toconductivity:
= per degree C
= per degree C
Common practice in the wire and cable industry is to refer all measurements ofcopper resistance to 25° C. (77° F.). At this temperature, the temperaturecoefficient is 0.00385 per degree C. or 0.00214 per degree F.
A value of copper resistance measured at any temperature in the range 0° - 50°C. (32° - 122° F.) may be corrected to the corresponding value at 25° C. (77°F.) bythe multiplying factor taken from the following table:
COPPER RESISTANCE - TEMPERATUREResistance Correction Factor
FERRAZ SHAWMUT
20
0
5
10
15
20
25
30
35
40
45
50
32
41
50
59
68
77
86
95
104
113
122
1.107
1.084
1.061
1.040
1.020
1.000
0.981
0.963
0.945
0.929
0.912
COPPER TEMPERATURE, DEGREES
Centigrade FahrenheitMULTIPLYING
FACTOR
0.0407ohms (mil, foot) at t °C
0.0226ohms (mil, foot) at t °C
FERRAZ SHAWMUT
21
COMPARATIVE DATA OF STRANDEDCOPPER AND ALUMINUM CABLES
3028262422201816141210864321
1/02/03/04/025030035040050060070075080090010001250150017502000
100.5159.8254.1404.0642.41022162025804110653010380165102624041740526206636083690105600133100167800211600
---------------------------------------------
0.0510.0810.1230.2050.3260.5180.8231.312.083.315.268.3713.321.226.733.642.453.567.485.01071271521772032533043553804054565076347608871014
0.30420.48370.76921.2231.9453.0924.9177.81812.4319.7731.4349.9779.46126.4159.3200.9253.3319.5402.8507.9640.57629151068122015251830213522882440274530503813457553386100
0.09240.1470.2340.3710.5910.9391.492.373.786.009.5515.224.139.049.062.078.1971231551952302763223684695526446907368289201150138016101840
1.6062.5544.0616.45810.2716.3325.9641.2865.64104.4165.9263.9419.6667.1841.3106113381687212726823382402648315636644280529662112731207812883144941610420130241602818032210
0.4880.7761.2361.9593.1204.9587.8712.520.031.750.480.31272062603274125136478161028121514581701192424772916340236453888437448606075729085059720
SIZE AREA WEIGHTS
AWG/ Circular Square POUNDS PER KFT POUNDS PER MILE
kcMil Mils Millimeters Copper Aluminum Copper Aluminum
FERRAZ SHAWMUT
22
COMPARATIVE DATA OF STRANDEDCOPPER AND ALUMINUM CABLES,cont.
181816161414121210108864321
1/02/03/04/025030035040050060070075080090010001250150017502000
16201620258025804110411065306530103801038016510165102624041740526206636083690105600133100167800211600
---------------------------------------------
1717171717177777191919191937373737376161616161619191127127
---0.015
---0.019
---0.024
---0.030
---0.038
---0.0490.0610.0770.0870.0970.0660.0740.0840.0940.1060.0820.0900.0970.1040.1160.0990.1070.1110.1140.1220.1280.1170.1280.1170.126
0.0400.0460.0510.0580.0640.0730.0810.0920.1020.1160.1280.1460.1840.2320.2600.2920.3320.3730.4190.4700.5280.5750.6300.6810.7280.8130.8930.9640.9981.031.091.151.291.411.521.63
0.0010.0020.0020.0030.0030.0040.0050.0060.0080.0110.0130.0170.0270.0420.0530.0670.0870.1090.1380.1730.2190.2600.3120.3640.4160.5190.6260.7300.7820.8340.9401.041.301.571.832.09
7.777.954.894.993.073.141.931.981.211.240.7640.7780.4910.3080.2450.1940.1540.1220.09670.07660.06080.05150.04290.03670.03210.02580.02140.01840.01710.01610.01430.01290.01030.008580.007350.00643
12.813.18.058.215.065.173.183.252.002.041.261.280.8080.5080.4030.3190.2530.2010.1590.1260.1000.08470.07070.06050.05290.4240.03530.03030.02820.02650.02350.02120.01690.01410.01210.0106
SIZE AREA STRANDS Diameter Area DC RESISTANCE
AWG/ CircularNumber Diameter
Overall Square Copper Aluminum
kcMil Mils Inches Inches Ohms/kFt Ohms/kFt
FERRAZ SHAWMUT
23
60°C 75°C 90°C 60°C 75°C 90°C(140°F) (167°F) (194°F) (140°C) (167°C) (194°F)
TYPES TYPES TYPES TYPES TYPES TYPESTW✝ FEPW✝ TA,TBS,SA TW✝ RH✝,RHW✝, TA,TBSUF✝ RH✝,RHW✝, SIS,FEP✝, UF✝ THHW✝, SA,SIS,
THHW✝, FEPB✝,MI THW✝, THHN✝,THW✝, RHH✝,RHW-2 THWN✝, THHW✝,
THWN✝, THHN✝,THHW✝, XHHW✝, THW-2,THWN-2,XHHW✝, THW-2,THWN-2, USE✝ RHH✝,RHW-2
USE✝,ZW✝ USE-2,XHH, USE-2XHHW✝ XHH,XHHW
XHHW-2,ZW-2 XHHW-2,ZW-2
NATIONAL ELECTRICAL CODE - 1999Table 310-16. Allowable Ampacities of Single Insulated Conductors
Rated 0-2000 Volts, 60° to 90°C (140° to 194°F)Not more than three conductors in Raceway or Cable or Earth
(Directly Buried), Based on Ambient Temperature of 30°C (86°F)
Temperature Rating of Conductor, See Table 310-13Size Size
AWG/kcmil
AWG/kcmil
COPPER ALUMINUM OR COPPER CLAD ALUMINUM18 --- --- 14 --- --- --- ---16 --- --- 18 --- --- --- ---14 20✝ 20✝ 25✝ --- --- --- ---12 25✝ 25✝ 30✝ 20✝ 20✝ 25✝ 1210 30 35✝ 40✝ 25 30✝ 35✝ 108 40 50 55 30 40 45 86 55 65 75 40 50 60 64 70 85 95 55 65 75 43 85 100 110 65 75 85 32 95 115 130 75 90 100 21 110 130 150 85 100 115 1
1/0 125 150 170 100 120 135 1/02/0 145 175 195 115 135 150 2/03/0 165 200 225 130 155 175 3/04/0 195 230 260 150 180 205 4/0250 215 255 290 170 205 230 250300 240 285 320 190 230 255 300350 260 310 350 210 250 280 350400 280 335 380 225 270 305 400500 320 380 430 260 310 350 500600 355 420 475 285 340 385 600700 385 460 520 310 375 420 700750 400 475 535 320 385 435 750800 410 490 555 330 395 450 800900 435 520 585 355 425 480 900
1000 455 545 615 375 445 500 10001250 495 590 665 405 485 545 12501500 520 625 705 435 520 585 15001750 545 650 735 455 545 615 17502000 560 665 750 470 560 630 2000
21-25 1.08 1.05 1.04 1.08 1.05 1.04 70-7726-30 1.00 1.00 1.00 1.00 1.00 1.00 78-8631-35 .91 .94 .96 .91 .94 .96 87-9536-40 .82 .88 .91 .82 .88 .91 96-10441-45 .71 .82 .87 .71 .82 .87 105-11346-50 .58 .75 .82 .58 .75 .82 114-12251-55 .41 .67 .76 .41 .67 .76 123-13156-60 --- .58 .71 --- .58 .71 132-14061-70 --- .33 .58 --- .33 .58 142-15871-80 --- --- .41 --- --- .41 159-176
CORRECTION FACTORSAmbientTemp °C
For ambient temperatures other than 30° C (86°F), multiply the allowableampacities shown above by the appropriate factor shown below.
AmbientTemp °C
✝Unless otherwise specifically permitted elsewhere in this Code, the overcurrent protection for conductor typesmarked with an obelisk (✝) shall not exceed 15 amperes for No.14, 20 amperes for No. 12, and 30 amperes forNo. 10 copper; or 15 amperes for No. 12 and 25 amperes for No. 10 aluminum and copper-clad aluminum afterany correction factors for ambient temperature and number of conductors have been applied.
60°C 75°C 90°C 60°C 75°C 90°C(140°F) (167°F) (194°F) (140°C) (167°C) (194°F)
TYPES TYPES TYPES TYPES TYPES TYPESTW✝ FEPW✝ TA,TBS,SA TW✝ RH✝,RHW✝, TA,TBSUF✝ RH✝,RHW✝, SIS,FEP✝ UF✝ THHW✝ SA,SIS,
THHW✝, FEPB✝,MI THW✝, THHN✝,THW✝, RHH✝,RHW-2 THWN✝ THHW✝
THWN✝ THHN✝,THHW✝, XHHW✝, THW-2,THWN-2,XHHW✝, THW-2,THWN-2, RHH✝,RHW-2
ZW✝ USE-2,XHH, USE-2XHHW✝ XHH,XHHW
XHHW-2,ZW-2 XHHW-2,ZW-2
FERRAZ SHAWMUTNATIONAL ELECTRICAL CODE - 1999
Table 310-17. Allowable Ampacities of Single Insulated ConductorsRated 0-2000 Volts, In Free Air
Based on Ambient Temperature of 30°C (86°F)
24
Temperature Rating of Conductor, See Table 310-13Size Size
AWG/kcmil
AWG/kcmil
COPPER ALUMINUM OR COPPER CLAD ALUMINUM18 --- --- 18 --- --- --- ---16 --- --- 24 --- --- --- ---14 25✝ 30✝ 35✝ --- --- --- ---12 30✝ 35✝ 40✝ 25✝ 30✝ 35✝ 1210 40 50✝ 55✝ 35 40✝ 40✝ 108 60 70 80 45 55 60 86 80 95 105 60 75 80 64 105 125 140 80 100 110 43 120 145 165 95 115 130 32 140 170 190 110 135 150 21 165 195 220 130 155 175 1
1/0 195 230 260 150 180 205 1/02/0 225 265 300 175 210 235 2/03/0 260 310 350 200 240 275 3/04/0 300 360 405 235 280 315 4/0250 340 405 455 265 315 355 250300 375 445 505 290 350 395 300350 420 505 570 330 395 445 350400 455 545 615 355 425 480 400500 515 620 700 405 485 545 500600 575 690 780 455 540 615 600700 630 755 855 500 595 675 700750 655 785 885 515 620 700 750800 680 815 920 535 645 725 800900 730 870 985 580 700 785 900
1000 780 935 1055 625 750 845 10001250 890 1065 1200 710 855 960 12501500 980 1175 1325 795 950 1075 15001750 1070 1280 1445 875 1050 1185 17502000 1155 1385 1560 960 1150 1335 2000
21-25 1.08 1.05 1.04 1.08 1.05 1.04 70-7726-30 1.00 1.00 1.00 1.00 1.00 1.00 78-8631-35 .91 .94 .96 .91 .94 .96 87-9536-40 .82 .88 .91 .82 .88 .91 96-10441-45 .71 .82 .87 .71 .82 .87 105-11346-50 .58 .75 .82 .58 .75 .82 114-12251-55 .41 .67 .76 .41 .67 .76 123-13156-60 --- .58 .71 --- .58 .71 132-14061-70 --- .33 .58 --- .33 .58 141-15871-80 --- --- .41 --- --- .41 159-176
CORRECTION FACTORSAmbientTemp °C
For ambient temperatures other than 30° C (86°F), multiply the allowableampacities shown above by the appropriate factor shown below.
AmbientTemp °F
✝Unless otherwise specifically permitted elsewhere in this Code, the overcurrent protection for conductor typesmarked with an obelisk (✝) shall not exceed 15 amperes for No.14, 20 amperes for No. 12, and 30 amperes forNo. 10 copper; or 15 amperes for No. 12 and 25 amperes for No. 10 aluminum and copper-clad aluminum afterany correction factors for ambient temperature and number of conductors have been applied.
CANADIAN ELECTRICAL CODE - 1998TABLE 1
(See Rules 4-004, 8-104, 12-2212, 26-000,26-742, 42-008 and 42-016 and Tables 5A, 5B, 19 and D3)
Allowable Ampacities forSingle Copper Conductors in Free Air
Based on Ambient Temperature of 30°C*
Allowable Ampacity†60°C I= 75°C I= 85 - 90°C I= 110°C I= 125°C I= 200°C I=
TypesR90, RW90
Size Types T90 NYLON See SeeAWG Type RW75 Single-Conductor Note Note Bare
kcmil TW TW75 Mineral-Insulated (3) (3) Wire
Cables§
FERRAZ SHAWMUT
25
Notes: See next page.
1412108
64321
0000000000
250300350400500
600700750800900
10001250150017502000
Col. 1
20254055
80105120140165
195225260300
340375420455515
575630655680730
78089098010701155
Col. 2
20254065
95125145170195
230265310360
405445505545620
690755785815870
9351065117512801385
Col. 3
40506585
120160180210245
285330385445
495555610665765
8559409801020
---
1165---
1450---
1715
Col. 5
40507090
125170195225265
305355410475
530590655710815
910100510451085
---
1240------------
Col. 6
455575100
135180210240280
325370430510
---------------
---------------
---------------
Col. 7
20254070
100135155180210
245285330385
425480530575660
740815845880940
10001130126013701470
Col. 4
FERRAZ SHAWMUT
26
TABLE 1 (CONCLUDED)
* See Table 5A for the correction factors to be applied to thevalues in Columns 2 to 7 for ambient temperatures over 30°C.
† The ampacity of single-conductor aluminum-sheathed cable isbased on the type of insulation used on the copper conductor.
I= These are maximum allowable conductor temperatures forsingle conductors run in free air and may be used in determiningthe ampacity of other conductor types in Table 19, which are sorun as follows: From Table 19 determine the maximum allowableconductor temperature for that particular type; then from Table 1determine the ampacity under the column of correspondingtemperature rating.
§ These ratings are based on the use of 90°C insulation on theemerging conductors and for sealing. Where a deviation has beenallowed in accordance with Rule 2-030, mineral-insulated cablemay be used at higher temperatures without decrease in allowableampacity, provided that insulation and sealing material approvedfor such higher temperature is used.
NOTES: (1) The ratings of Table 1 may be applied to a conductormounted on a plane surface of masonry, plaster,wood, or any material having a conductivity not lessthan 0.4W/(m°C).
(2) For correction factors where from 2 to 4 conductorsare present and in contact see Table 5B.
(3) These ampacities are only applicable under specialcircumstances where the use of insulated conductorshaving this temperature rating are acceptable.
(4) Type R90 silicone wiring may be used in ambienttemperatures up to 65°C without applying thecorrection factors for ambient temperatures above30°C provided the temperature of the conductor atthe termination does not exceed 90°C.
FERRAZ SHAWMUT
27
Allowable Ampacity ✝ ‡ ‡60°C I= 75°C I= 85 - 90°C I= 110°C I= 125°C I= 200°C I=
TypesR90, RW90
Size Types T90 NYLON See See SeeAWG Type RW75 Paper Note Note Notekcmil TW TW75
Mineral-Insulated(1) (1) (1)
Cable**
Notes: See next page.
1412108
64321
0000000000
250300350400500
600700750800900
10001250150017502000
Col. 1
15203040
55✝✝7080100110
125145165195
215240260280320
355385400410435
455495520545560
Col. 2
15203045
6585100115130
150175200230
255285310335380
420460475490520
545590625650665
Col. 3
30354560
80105120135160
190215245275
315345390420470
525560580600---
680---
785---
840
Col. 5
30405065
85115130145170
200230265310
335380420450500
545600620640---
730------------
Col. 6
30405570
95120145165190
225250285340
---------------
---------------
---------------
Col. 7
15203045
6585105120140
155185✝✝210235
265295325345395
455490500515555
585645700735775
Col. 4
CANADIAN ELECTRICAL CODE - 1998TABLE 3
(See Rules 4-004, 8-104, 12-2212, 26-000,26-742, 42-008 and 42-016 and Tables 5A, 5C, 19 and D3)
Allowable Ampacities for Not More Than3 Copper Conductors in Raceway or Cable
Based on Ambient Temperature of 30°C*
FERRAZ SHAWMUT
28
TABLE 2 (CONCLUDED)
* See Table 5A for the correction factors to be applied to the valuesin Columns 2 to 7 for ambient temperatures over 30°C.
† The ampacity of aluminum-sheathed cable is based on the type ofinsulation used on the copper conductor.
I= These are maximum allowable conductor temperatures for 1, 2 or3 conductors run in a raceway, or 2 or 3 conductors run in a cableand may be used in determining the ampacity of other conductortypes in Table 19, which are so run as follows: From Table 19determine the maximum allowable conductor temperature for thatparticular type; then from Table 2 determine the ampacity underthe column of corresponding temperature rating.
** These ratings are based on the use 90°C insulation on theemerging conductors and for sealing. Where a deviation hasbeen allowed in accordance with Rule 2-030, mineral-insulatedcable may be used at higher temperatures without decrease inallowable ampacity, provided that insulation and sealing materialapproved for such higher temperature is used.
†† For 3-wire 120/240 and 120/208 V residential services or sub-services, the allowable ampacity for sizes No. 6 and No. 2/0AWG shall be 60 A and 200 A respectively. In this case, the 5%adjustment of Rule 8-106(1) cannot be applied.
I= I=See Table 5C for the correction factors to be applied to the valuesin Columns 2 to 7 where there are more than 3 conductors in arun of raceway or cable.
NOTES: (1) These ampacities are only applicable under specialcircumstances where the use of insulated conductorshaving this temperature rating are acceptable.
(2) Type R90 silicone wiring may be used in ambienttemperatures up to 65°C without applying thecorrection factors for ambient temperatures above30°C provided the temperature of the conductor atthe termination does not exceed 90°C.
FERRAZ SHAWMUT
29
Allowable Ampacity†
60°C I= 75°C I= 85 - 90°C I= 110°C I= 125°C I= 200°C I=Size Types Types See SeeAWG Type RW75 R90, RW90 Note Note Barekcmil TW TW75 T90 NYLON (3) (3) Wire
Notes: See next page.
121086
4321
0000000000
250300350400500
600700750800900
10001250150017502000
Col. 1
20304560
8095110130
150175200230
265290330355405
455500515535580
625710795875960
Col. 2
20304575
100115135155
180210240280
315350395425485
545595620645700
75085595010501150
Col. 3
40506595
125140165190
220225300345
385435475520595
675745775805---
930---
1175---
1425
Col. 5
405570100
135150175205
240275320370
415460510555635
720795825855---
990------------
Col. 6
456080105
140165185220
255290335400
---------------
---------------
--------------
Col. 7
20304580
105120140165
190220255300
330375415450515
585645670695750
800905102011251220
Col. 4
CANADIAN ELECTRICAL CODE - 1998
TABLE 3(See Rules 4-004, 8-104, 12-2212, 26-000,
26-742, 42-008 and 42-016 and Tables 5A, 5B, and D3)
Allowable Ampacities forSingle Aluminum Conductors in Free Air
Based on Ambient Temperature of 30°C*
FERRAZ SHAWMUT
30
TABLE 3 (CONCLUDED)
* See Table 5A for the correction factors to be applied to the valuesin Columns 2 to 7 for ambient temperatures over 30°C.
† The ampacity of single-conductor aluminum-sheathed cable isbased on the type of insulation used on the copper conductor.
I= These are maximum allowable conductor temperatures for singleconductors run in free air and may be used in determining theampacity of other conductor types in Table 19, which are so runas follows: From Table 19 determine the maximum allowableconductor temperature for that particular type; then from Table 3determine the ampacity under the column of correspondingtemperature rating.
NOTES: (1) The ratings of Table 3 may be applied to a conductormounted on a plane surface of masonry, plaster,wood, or any material having a conductivity not lessthan 0.4 W/(m°C).
(2) For correction factors where from 2 to 4 conductorsare present and in contact see Table 5B.
(3) These ampacities are only applicable under specialcircumstances where the use of insulated conductorshaving this temperature rating are acceptable.
FERRAZ SHAWMUT
31
CANADIAN ELECTRICAL CODE - 1998
TABLE 4(See Rules 4-004, 8-104, 12-2212, 26-000,
26-742, 42-008 and 42-016 and Tables 5A, 5C, and D3)
Allowable Ampacities for Not More than3 Aluminum Conductors in Raceway or Cable
Based on Ambient temperature of 30°C*
Allowable Ampacity† §
60°C I= 75°C I= 85 - 90°C I= 110°C I= 125°C I= 200°C I=
Paper
Notes: See next page.
121086
4321
0000000000
250300350400500
600700750800900
10001250150017502000
15253040
55657585
100115130155
170190210225260
285310320330355
375405435455470
15253050
657590100
120135155180
205230250270310
340375385395425
445485520545560
25354560
8095105125
150170195215
250275310335380
425455470485---
560---
650---
705
30405065
90100115135
160180210245
270305335360405
440485500520---
600------------
30455575
95115130150
180200225270
---------------
---------------
---------------
152530
55**
6575
95**105
120145165
185**
215240260290330
370395405415455
480530580615650
TypeTW
TypesRW75TW75
SizeAWGkcmil
TypesR90, RW90T90 NYLON
See Note
See Note
Col. 1 Col. 2 Col. 3 Col. 4 Col. 5 Col. 6 Col. 7
See Note
FERRAZ SHAWMUT
32
TABLE 4 (CONCLUDED)
* See Table 5A for the correction factors to be applied to the valuesin Columns 2 to 7 for ambient temperatures over 30°C.
† The ampacity of aluminum-sheathed cable is based on the type ofinsulation used on the copper conductor.
I= These are maximum allowable conductor temperatures for 1, 2 or3 conductors run in a raceway, or 2 or 3 conductors run in a cableand may be used in determining the ampacity of other conductortypes in Table 19, which are so run as follows: From Table 19determine the maximum allowable conductor temperature for thatparticular type; then from Table 4 determine the ampacity underthe column of corresponding temperature rating.
§ See Table 5C for the correction factors to be applied to the valuesin Columns 2 to 7 where there are more than 3 conductors in arun of raceway or cable.
** For 3-wire 120/240 and 120/208 V residential services or subser-vices, the allowable ampacity for sizes No. 6 and No 2 and No.4/0 AWG shall be 60 A, 100 A and 200 A respectively. In this case,the 5% adjustment of Rule 8-106(1) cannot be applied.
NOTES: (1) These ampacities are only applicable under specialcircumstances where the use of insulated conductorshaving this temperature rating are acceptable.
FERRAZ SHAWMUT
33
Allowable Short Circuit Currents for Insulated AluminumConductors (90°C-RHH, RHW-2, XHH, XHHW, Etc.)
SH
OR
T C
IRC
UIT
CU
RR
EN
T I
N A
MP
ER
ES
1000009000080000700006000050000
40000
30000
20000
1000090008000700060005000
4000
3000
2000
1000900800700600500
400
300
200
100
10 8 6 4 2 1 1/02/03/04/0
250 500 1000CONDUCTOR SIZE
(MCM)
Source: Insulated Cable Engineers Association
CONDUCTOR - ALUMINUMINSULATION -CROSSLINKED POLYETHYLENE ÐYLENE PROPYLENE RUBBER
CURVES BASED ON FORMULA
I 2 T 2 + 228 — t = .0125 Log ——————-A T 1 + 228
WHERE
I = SHORT CIRCUIT CURRENT AMPERESA = CONDUCTOR AREA-CIRCULAR MILSt = TIME OF SHORT CIRCUIT-SECONDS T = MAXIMUM OPERATING
1TEMPERATURE -90°C
T = MAXIMUM SHORT CIRCUIT2
TEMPERATURE -250°C
1 CYCLE -
0.01
67 S
ECONDS
2 CYCLE -
0.03
33 S
ECONDS
4 CYCLE -
0.06
67 S
ECONDS
8 CYCLE -
0.13
33 S
ECONDS
16 C
YCLE - 0.
2667
SECONDS
30 C
YCLE - 0.
5000
SECONDS
60 C
YCLE - 1.
0000
SECONDS
100
CYCLE - 1.
6667
SECONDS
[ [ ]]
CONDUCTOR SIZE(AWG)
FERRAZ SHAWMUT
34
Allowable Short Circuit Currents for Insulated AluminumConductors (75°C-RH, RHW, THW, THHW, THWN, Etc.)
SH
OR
T C
IRC
UIT
CU
RR
EN
T I
N A
MP
ER
ES
1000009000080000700006000050000
40000
30000
20000
1000090008000700060005000
4000
3000
2000
1000900800700600500
400
300
200
100
10 8 6 4 2 1 1/02/03/04/0
250 500 1000CONDUCTOR SIZE
(MCM)
Source: Insulated Cable Engineers Association
CONDUCTOR - ALUMINUMINSULATION - THERMOPLASTIC
CURVES BASED ON FORMULA
I 2 T 2 + 228 — t = .0125 Log ——————-A T 1 + 228
WHERE
I = SHORT CIRCUIT CURRENT AMPERESA = CONDUCTOR AREA-CIRCULAR MILSt = TIME OF SHORT CIRCUIT-SECONDS T = MAXIMUM OPERATING
1TEMPERATURE 75°C
T = MAXIMUM SHORT CIRCUIT2
TEMPERATURE 150°C
1 CYCLE -
0.01
67 S
ECONDS
2 CYCLE -
0.03
33 S
ECONDS
4 CYCLE -
0.06
67 S
ECONDS
8 CYCLE -
0.13
33 S
ECONDS
16 C
YCLE - 0.
2667
SECONDS
30 C
YCLE - 0.
5000
SECONDS
60 C
YCLE - 1.
0000
SECONDS
100
CYCLE - 1.
6667
SECONDS
[ [ ]]
CONDUCTOR SIZE(AWG)
FERRAZ SHAWMUT
35
Allowable Short Circuit Currents for Insulated CopperConductors (90°C-FEP, RHH, XHH, XHHW, Etc.)
SH
OR
T C
IRC
UIT
CU
RR
EN
T I
N A
MP
ER
ES
10 8 6 4 2 1 1/02/03/04/0
250 500 1000CONDUCTOR SIZE
(MCM)
Source: Insulated Cable Engineers Association
CONDUCTOR - COPPERINSULATION -CROSSLINKED POLYETHYLENE ÐYLENE PROPYLENE RUBBER
CURVES BASED ON FORMULA
I 2 T 2 + 234 — t = .0297 Log ——————-A T 1 + 234
WHERE
I = SHORT CIRCUIT CURRENT AMPERESA = CONDUCTOR AREA-CIRCULAR MILSt = TIME OF SHORT CIRCUIT-SECONDS T = MAXIMUM OPERATING
1TEMPERATURE 90°C
T = MAXIMUM SHORT CIRCUIT2
TEMPERATURE 250°C
1 CYCLE -
0.01
67 S
ECONDS
2 CYCLE -
0.03
33 S
ECONDS
4 CYCLE -
0.06
67 S
ECONDS
8 CYCLE -
0.13
33 S
ECONDS
16 C
YCLE - 0.
2667
SECONDS
30 C
YCLE - 0.
5000
SECONDS
60 C
YCLE - 1.
0000
SECONDS
100
CYCLE - 1.
6667
SECONDS
[ [ ]]
CONDUCTOR SIZE(AWG)
1000009000080000700006000050000
40000
30000
20000
1000090008000700060005000
4000
3000
2000
1000900800700600500
400
300
200
100
FERRAZ SHAWMUT
36
Allowable Short Circuit Currents for Insulated CopperConductors (75°C-RH, RHW, THW, THHW, THWN, Etc.)
SH
OR
T C
IRC
UIT
CU
RR
EN
T I
N A
MP
ER
ES
1000009000080000700006000050000
40000
30000
20000
1000090008000700060005000
4000
3000
2000
1000900800700600500
400
300
200
100
10 8 6 4 2 1 1/02/03/04/0
250 500 1000CONDUCTOR SIZE
(MCM)
Source: Insulated Cable Engineers Association
CONDUCTOR - COPPERINSULATION - THERMOPLASTIC
CURVES BASED ON FORMULA
I 2 T 2 + 234 — t = .0297 Log ——————-A T 1 + 234
WHERE
I = SHORT CIRCUIT CURRENT AMPERESA = CONDUCTOR AREA-CIRCULAR MILSt = TIME OF SHORT CIRCUIT-SECONDS T = MAXIMUM OPERATING
1TEMPERATURE 90°C
T = MAXIMUM SHORT CIRCUIT2
TEMPERATURE 250°C
1 CYCLE -
0.01
67 S
ECONDS
2 CYCLE -
0.03
33 S
ECONDS
4 CYCLE -
0.06
67 S
ECONDS
8 CYCLE -
0.13
33 S
ECONDS
16 C
YCLE - 0.
2667
SECONDS
30 C
YCLE - 0.
5000
SECONDS
60 C
YCLE - 1.
0000
SECONDS
100
CYCLE - 1.
6667
SECONDS
[ [ ]]
CONDUCTOR SIZE(AWG)
FERRAZ SHAWMUT
37
WIRE CALCULATIONS
Ohm’s Law
Ohm’s Law: I = , where I is current;
E is voltage; and R is resistance.
Example: With a voltage of 112 and a resistance of 8 ohms what current would flow?
I = or 14 amperes
Example: What resistance is necessary to obtain a current of 14 amperes
at 112 volts?
R= or R = or 8 ohms.
Example: What voltage would be required to produce a flow of 14 amperes
through a resistance of 8 ohms?
E = IR or E = 14 x 8 or 112 volts
Voltage Drop
The resistance of a copper wire one foot long and one circular mil in cross
section is approximately 10.8 ohms. (Aluminum = 17.0 ohms).
In Ohm’s law I = ,R is equal to: Length conductor in feet x 10.8 divided
by the circular mills of the conductor or,
R =
Using Ohm’s law, E = IR
E =
where the term “feet” indicates the length of the circuit, the number of feet of wire
in the circuit being double the length of the circuit.
Example: What would be the volts drop in a circuit of No. 12 wire carrying 20
amperes a distance of 50 feet? (Find CM on page 21).
E = or 3.3 volts drop, or 3% on a 110-volt circuit
1128
E R
11214
2 x feet (length of circuit) x 10.8
CM
Amps x 2 x feet x 10.8
CM
E I
20 x 2 x 50 x 10.8
6530
E R
FERRAZ SHAWMUT
38
Example: What size of conductor would be necessary to give a 3% drop on a
110 volt circuit carrying 20 amperes a distance of 50 feet?
C = or
CM = or 6545 CM or a No. 12 wire.
Example: What current can a No. 12 wire carry on a 50 foot circuit with a voltage
drop of 3.3 volts.
Amp. = or
I = or 20 amperes.
Current Calculations
The formula W = EI, where W = watts; E = voltage; I = current, can be used to
determine the watts, W = EI; the voltage E = ; or the current, I = .
This formula is applicable where the power-factor is unity. To determine the
current.
2-Wire, Direct Current: I = .
3-Wire, Direct Current: I = where E is the voltage between the outside
wire and the neutral.
2-Wire, Single-Phase: I = , where PF represents the power factor of
the circuit.
3-Wire, Single-Phase: I = , where E is voltage between the outside
wire and the neutral.
3-Wire and 4-Wire, Three-Phase: I = , where E is the voltage
between outside wires.
W I
Amps x 2 x feet x 10.8
CM
20 x 2 x 50 x 10.8
3.3
CM x E 2 x feet x10.8
6545 x 3.3 50 x 2 x 10.8
W E
W
E
W E x PF
W 2E x PF
W 1.73 E x PF
W
2E
FERRAZ SHAWMUT
39
VO
LTA
GE
DR
OP
Dir
ect
Cu
rren
t o
r 10
0% P
ow
er F
acto
r A
lter
nat
ing
Cu
rren
t C
ircu
its
Fro
m t
he
Han
db
oo
k o
f In
teri
or
Wir
ing
Des
ign
Thi
s ta
ble
can
be u
sed
only
for
d-c
or
100%
pow
er f
acto
r a-
c lo
ads
such
as
sing
le p
hase
2 o
r 3
wire
, 3
phas
e 3
or 4
wire
inca
ndes
cent
lam
p ci
rcui
ts;
resi
stan
ce t
ype
heat
ing
units
; o
r un
ity p
ower
fac
tor
mot
ors.
All
calc
ulat
ions
are
bas
ed o
n a
copp
er t
empe
ratu
re o
f 49
°C.
KIL
O-A
MP
ER
E F
EE
T
Wir
e S
ize
Vo
lts
Dro
p
12
34
56
78
9
.177
.282
.448
.712
1.11
1.76
2.88
3.54
4.46
5.62
7.08
8.92
10.5
12.6
14.7
16.7
20.8
30.5
39.5
.354
.563
.895
1.42
2.22
3.53
5.75
7.07
8.91
11.2
14.2
17.8
21.0
25.2
29.3
33.4
41.5
60.9
79.0
.531
.845
1.34
2.14
3.33
5.29
8.63
10.6
13.4
16.9
21.2
26.7
31.6
37.8
44.0
50.2
62.3
91.4
118.
.705
1.13
1.79
2.85
4.44
7.06
11.5
14.1
17.8
22.5
28.3
35.7
42.1
50.4
58.7
66.9
83.1
122.
158.
.866
1.41
2.24
3.56
5.55
8.82
14.4
17.7
22.3
28.1
35.4
44.6
52.6
63.0
73.3
83.6
104.
152.
198.
1.06
1.69
2.69
4.27
6.66
10.6
17.3
21.2
26.7
33.7
42.5
53.5
63.1
75.6
88.0
100.
125.
183.
237.
1.06
1.97
3.13
4.98
7.77
12.3
20.1
24.8
31.2
39.3
49.6
62.4
73.7
88.2
103.
117.
145.
213.
277.
1.24
2.25
3.58
5.69
8.88
14.1
23.0
28.3
35.6
44.9
56.6
71.3
84.2
101.
117.
134.
166.
244.
316.
1.77
2.82
4.48
7.12
11.1
17.6
28.8
35.4
44.6
56.2
70.8
89.2
105.
126.
147.
167.
208.
305.
395.
14 12 10 8 6 4 2 1 1/0
2/0
3/0
4/0
250,
000
cm30
0,00
0 cm
350,
000
cm40
0,00
0 cm
500,
000
cm75
0,00
0 cm
1,00
0,00
0 cm
Note: See next page for examples.
FERRAZ SHAWMUT
40
USE OF VOLTAGE DROP TABLE1. To Find The Size of Wire Required for a Given Line Drop in Volts:a. Find the “kilo-ampere feet”by multiplying the current in amperes by the length of
of one wire in feet (not the total length of wire in the circuit) and dividing by 1,000.
b. Starting with the given voltage drop, follow the column down to the number of kilo-ampere feet nearest to the actual number calculated. Follow the horizontalline and find the correct size of wire at the extreme left column.
c. With very short runs, the table may indicate that a size of wire smaller than permitted by Code regulations will hold the voltage drop within the limitsdesired. In such cases, the wire size must be increased to meet the Coderequirements.
2. To Find the Drop in Volts, Which Will be Produced by a Given Size of Wire:a. Find the kilo-ampere feet as above.b. Starting with the given size of wire, follow the horizontal line to the right to the
number of kilo-ampere feet nearest the actual number calculated. Follow thiscolumn up and find the drop in volts.
3. Example A 23-KW balanced lighting load is to be supplied from 3-wire, 120-240 volt mains.The length of the run between service switch and distribution panel is 250 feet.The voltage drop is not to exceed 2 per cent. What size of conductor should beused? Solution:
On a balanced 3-wire system, the current in each of the outside wires would be calculated as follows:
= 95.8 amperes
The kilo-ampere feet would equal:
= 22.0 kilo-ampere feet
Since the permitted percentage voltage drop is 2, the actual drop permitted is:
.02 x 240 = 4.8 volts
To determine the wire size required, start at the top of column marked 5 volts(which is nearest to 4.8). Follow down until the figure 22.3 is reached (which isnearest 22.0) This would indicate the use of 1/0 conductors. The actual drop wouldthen be:
x 5 volts = 4.93 volts
This degree of error (2.05 per cent instead of 2 per cent) is entirely permissiblefor feeder design.
23 K.W x 1,000 (conversion to watts)
240 V.
95.8 amperes x 250 ft.
1,000
22.0
22.3
Th
ree-
Ph
ase
Lin
e-to
-Lin
e V
olt
age
Dro
p f
or
600
V S
ing
le-C
on
du
cto
r C
able
per
10,
000
A-f
t.60
°C C
on
du
cto
r Te
mp
erat
ure
, 60
Hz
(IE
EE
)
Load
Pow
erW
ire S
ize
(AW
G o
r kcm
il)Fa
ctor
Lagg
ing
1000
900
800
750
700
600
500
400
350
300
250
4/0
3/0
2/0
1/0
12
46
1.00
0.95
0.90
0.80
0.70
1.00
0.95
0.90
0.80
0.70
1.00
0.95
0.90
0.80
0.70
1.00
0.95
0.90
0.80
0.70
0.28
0.50
0.57
0.66
0.71
0.23
0.40
0.47
0.54
0.57
0.42
0.62
0.69
0.76
0.80
0.36
0.52
0.57
0.63
0.66
0.31
0.52
0.59
0.68
0.73
0.26
0.43
0.48
0.55
0.59
0.45
0.69
0.72
0.80
0.83
0.39
0.56
0.61
0.66
0.69
0.34
0.55
0.62
0.71
0.76
0.28
0.45
0.52
0.57
0.62
0.49
0.70
0.76
0.83
0.87
0.44
0.60
0.65
0.71
0.73
0.35
0.57
0.64
0.73
0.78
0.29
0.47
0.54
0.59
0.64
0.52
0.73
0.79
0.85
0.89
0.47
0.63
0.68
0.73
0.75
0.37
0.59
0.66
0.74
0.80
0.33
0.50
0.55
0.62
0.66
0.55
0.76
0.82
0.88
0.92
0.51
0.67
0.71
0.76
0.78
0.42
0.64
0.71
0.80
0.83
0.38
0.54
0.59
0.66
0.69
0.63
0.83
0.88
0.95
0.98
0.59
0.74
0.79
0.83
0.83
0.50
0.71
0.78
0.85
0.88
0.45
0.62
0.68
0.73
0.74
0.74
0.94
0.99
1.0
1.1
0.70
0.85
0.89
0.92
0.92
0.60
0.81
0.88
0.95
0.97
0.55
0.71
0.76
0.81
0.83
0.91
1.1
1.2
1.2
1.2
0.88
1.0
1.1
1.1
1.1
0.68
0.88
0.95
1.0
1.0
0.62
0.80
0.85
0.88
0.88
1.0
1.2
1.3
1.3
1.3
1.0
1.1
1.2
1.2
1.1
0.78
1.0
1.1
1.1
1.1
0.73
0.92
0.95
0.97
0.97
1.2
1.4
1.4
1.4
1.4
1.2
1.3
1.3
1.3
1.3
0.92
1.1
1.2
1.2
1.2
0.88
1.0
1.1
1.1
1.1
1.4
1.6
1.6
1.6
1.6
1.4
1.5
1.5
1.5
1.4
1.1
1.3
1.3
1.4
1.3
1.0
1.1
1.1
1.1
1.1
1.7
1.8
1.9
1.8
1.7
1.7
1.8
1.8
1.7
1.6
1.4
1.5
1.6
1.6
1.5
1.3
1.5
1.5
1.4
1.4
2.1
2.3
2.3
2.2
2.1
2.1
2.2
2.2
2.1
1.7
1.7
1.9
1.9
1.9
1.8
1.6
1.8
1.8
1.7
1.6
2.6
2.7
2.7
2.6
2.4
2.6
2.7
2.6
2.5
2.3
2.1
2.3
2.3
2.3
2.1
2.1
2.2
2.2
2.1
2.0
3.3
3.4
3.4
3.2
2.9
3.3
3.4
3.3
3.1
2.8
2.6
2.8
2.8
2.6
2.5
2.6
2.7
2.7
2.5
2.4
4.2
4.2
4.1
3.9
3.6
4.2
4.2
4.1
3.8
3.4
3.4
3.5
3.4
3.2
3.0
3.3
3.4
3.3
3.1
2.8
5.2
5.3
5.1
4.7
4.3
5.2
5.2
5.0
4.6
4.2
5.3
5.3
5.2
4.8
4.4
5.3
5.3
5.1
4.7
4.3
8.4
8.2
7.9
7.3
6.5
8.4
8.2
7.9
7.2
6.4
8.4
8.2
8.0
7.3
6.6
8.4
8.2
7.9
7.2
6.4
13 13 12 11 10 13 13 12 11 9.9
13 13 12 11 9.9
13 13 12 11 9.7
21 20 19 17 15 21 20 19 17 15
21 20 19 17 15 21 20 19 17 15 33 32 30 27 24 33 32 30 27 24
33 32 30 27 24 33 32 30 27 24 52 50 48 43 37 52 50 48 42 37
53 50 48 43 38 53 50 48 43 38
- - - - - - - - - -
FERRAZ SHAWMUT
41
Sec
tion
1: C
oppe
r C
ondu
ctor
s in
Mag
netic
Con
duit
Sec
tion
2: C
oppe
r C
ondu
ctor
s in
Non
mag
netic
Con
duit
Sec
tion
3: A
lum
inum
Con
duct
ors
in M
agne
tic C
ondu
it
Sec
tion
4: A
lum
inum
Con
duct
ors
in N
onm
agne
tic C
ondu
it
*Sol
id C
ondu
ctor
. O
ther
con
duct
ors
are
stra
nded
.
To c
onve
rt v
olta
ge d
rop
to
Mul
tiply
by
Sin
gle
phas
e, t
hree
wire
, lin
e to
line
1.18
Sin
gle
phas
e, t
hree
wire
, lin
e to
neu
tral
0.57
7T
hree
pha
se,
line
to n
eutr
al0.
577
8*
10
1
2*
14
*
FERRAZ SHAWMUT
42
VOLTAGE DROP TABLE I.A.E.I. Circuit Footage for 3 Per Cent Drop
COPPER CABLE
Size 3 6 15 20 25 35AWG/MCM Amps Amps Amps Amps Amps Amps
1816141210864321
1/02/03/04/0250300350400500600700
8313120933052884013362125268033794262537267788543
----------------
--6610416626442066810621340168921312686338942725387
--------------
----4266105168267424536679852107413551709215525463055
----------
------50791262003184025076398061016128116161911229126733055
------
--------631001602553214055116448131025129315271833213824443055
----
----------721141822292893654605817329231091130915261746218226193055
VOLTAGE DROP TABLE I.A.E.I. Circuit Footage for 3 Per Cent Drop
Size 50 70 80 90 100 125AWG/MCM Amps Amps Amps Amps Amps Amps
64321
1/02/03/04/0250300350400500600700
10012716020225532240551264676391610691222152718332138
--91114144182230290366461545654763873109113091527
----
10012615920125432040447757266776393411451336
------
11214217922528435942450959467984810181188
--------
1271612032563233814585346117639161069
----------
128162205258305366427488611733855
Size 325 400 450 500 525 550AWG/MCM Amps Amps Amps Amps Amps Amps
40050060070075080090010001100120013001400150016001700180019002000
188235282329352376423470517564611657705752799846892940
--190229267286305343381420458496534572611649687725763
----
203237254271305339373407441475509532577611645679
------
213229244275305336366397427458488519555580611
--------
218232261291320349378407436465495523555582
----------
222250277305333361388416444472500527555
Size 150 175 225 250 275 300AWG/MCM Amps Amps Amps Amps Amps Amps
2/03/04/025030035040050060070075080090010001100120013001400150016001700180019002000
13517021525430535640750961171276381491610181120122213241425152716281728183219322036
--143184218261305349436523611654698785873960104711341222130913961484157116641746
----
143169203237271339407475509543611679746814882950101810641154122212901358
------
1521832132443053664274584885506116727337948559169761038111011601222
--------
166194220277333389416444500555611666722777832888944100010541110
----------
1782032543053563814074585095606116627127638148649169661018
FERRAZ SHAWMUT
43
VOLTAGE DROP TABLE I.A.E.I. Circuit Footage for 3 Per Cent Drop
VOLTAGE DROP TABLE I.A.E.I., cont. Circuit Footage for 3 Per Cent Drop
FERRAZ SHAWMUT
44
Notes: Tables calculated for 110 volts dc. The footages shown are approximatefor single-phase and two-phase at unity power factor. For 3-phase, the abovefootage may be increased by approximately 12 percent. The following factorsmay be used for other voltages:
220 volts -- multiply by 2440 volts -- multiply by 4550 volts -- multiply by 52200 volts -- multiply by 20
For 1 percent drop, allow one third the footage shown. For 2 percent drop, allow
two-thirds the footage shown.
These tables compiled by G.M. Miller, Richmond, Virginia.
Size 600 650 690 730 770 810AWG/MCM Amps Amps Amps Amps Amps Amps
90010001100120013001400150016001700180019002000
229254280305331356381407432458483509
--235258282305328352376399423446470
----
243265287309332354376398420442
------
251272292313334355376397418
--------
258277297339361382403424
----------
264282301320339358377
VOLTAGE DROP TABLE I.A.E.I., cont. Circuit Footage for 3 Per Cent Drop
Size 850 890 930 970 1010 1050AWG/MCM Amps Amps Amps Amps Amps Amps
150016001700180019002000
269287305323341359
--274291308325343
----
279295312328
------
283299315
--------
287302
----------
291
VOLTAGE DROP TABLE I.A.E.I. Circuit Footage for 3 Per Cent Drop
FERRAZ SHAWMUT
45
LINE CURRENT AND VOLTAGE DROP
(Simplex Wire & Cable Co.)
In the following formulas for line current and voltage drop, the meaning of mostof the symbols will be found on the circuit diagrams. For completeness, they arealso defined here. It should be emphasized that the letter E with subscripts isalways used to designate circuit voltage. The primed values describe sendingend conditions; and unprimed values, receiving end conditions. The letter V withsubscripts always signifies a voltage drop.
Let I = line current, amps
E’o , Eo = sending and receiving end voltages to neutral, volts
E’l , El = sending and receiving end voltages between lines, volts
E’p , Ep = sending and receiving end voltages per phase, volts
Vo = E’o - Eo = voltage drop to neutral, volts
Vl = E’l - El = voltage drop between lines, volts
Vp = E’p - Ep = voltage drop per phase, volts
R = D.C. or A.C. resistance of line, ohms per1000 ft. perconductor
X = 60 cycle Reactance of line, ohms per 1000 ft. perconductor
Z = 60 cycle Impedance of line, ohms per 1000 ft. perconductor
I = length of line, feet
W = watts delivered
p.f. = cos q = power factor of load
q = power factor angle of load
There is a SHAWMUT fuse for every purpose. Where you can use a fuse, use aSHAWMUT fuse; for a SHAWMUT fuse is the fuse to use. SHAWMUT engineer-ing has seen to that, from the fullest experience in both shop and field, over aperiod of many years. Specify SHAWMUT fuses by name when you order fuses;it is the way to be sure that you will get the exact performance and protectionyou require.
FERRAZ SHAWMUT
46
D.C - 2 WIRE
D.C - 3 WIRE - BALANCED LOAD
A.C - SINGLE PHASE - 2 WIRE
FERRAZ SHAWMUT
47
A.C - SINGLE PHASE - 3 WIRE - BALANCED LOAD
FERRAZ SHAWMUT
48
When the line supplies a balanced load, the neutral wire carries no currentTherefore, the formulas are the same whether there is a neutral wire or not (4 or5-wire circuit).
A.C - THREE PHASE -3 OR 4 WIRE - BALANCED LOAD
When the line supplies a balanced load, the neutral wire carries no current.Therefore, the formulas are the same whether there is a neutral wire or not (3 or4 wire circuit).
When you buy SHAWMUT fuses, you buy experience and knowledge second tonone in fuse manufacture. And if you know fuses, you do buy SHAWMUT fuses.
FERRAZ SHAWMUT
49
FERRAZ SHAWMUT
50
�
US
EF
UL
EL
EC
TR
ICA
LF
OR
MU
LA
FO
R D
ET
ER
MIN
ING
AM
PE
RE
S,
HO
RS
EP
OW
ER
, K
ILO
WA
TT
S, A
ND
K.V
.A.
I =
Am
pere
s; E
= V
olts
; E
FF.
= E
ffici
ency
; P.
F. =
Pow
er F
acto
rK
.W.
= K
ilow
atts
; K
.V.A
. =
Kilo
-Vol
t-A
mpe
res;
H.P
. =
Hor
sepo
wer
*For
thr
ee w
ire,
two
phas
e ci
rcui
ts t
he c
urre
nt in
the
com
mon
con
duct
or is
1.4
1 tim
es t
hat
in e
ither
of
the
othe
r tw
o co
nduc
tors
.F
or a
vera
ge v
alue
s of
effi
cien
cy a
nd p
ower
fac
tor
see
page
54.
FERRAZ SHAWMUT
51
To F
ind
Am
pere
s w
hen
Hor
sepo
wer
is
know
n
Am
pere
s w
hen
Kilo
wat
ts a
re
Kno
wn
Am
pere
s w
hen
K.V
. A.
is k
now
n
Kilo
wat
ts
K.V
.A.
Hor
sepo
wer
(Out
put)
Dir
ect
Cu
rren
tS
ing
le-P
has
e
H.P
. x
746
E x
EF
F.
x P.
F.
K.W
. 1
000
E x
P.F
.
K.V
.A.
x 10
00E
I x
E x
P.F
.10
00
I x
E10
00
Two
-Ph
ase*
Fo
ur-
Wir
e
H.P
. x
746
2 x
ExE
FF.
x P.
F.
Th
ree-
Ph
ase
H.P
. x
746
1.73
x E
x E
FF.
x P.
F.
K.W
. x
1000
1.73
x E
x P
.F.
K.V
. A.x
100
0
1.73
x E
I x
E x
1.7
3 x
P.F.
1000
I x
E x
1.7
3
1000
I x
E x
1.7
3 x
EF
F.
x P.
F.
746
K.W
. x
1000
2 x
E x
P.F
.
K.V
. A.
x 10
00
2 x
E
I x
E x
2 x
P.F
.
1000
I x
E x
2
1000
I x
E x
2 x
EF
F.
x P.
F.
746
I x
E x
EF
F.
x P.
F.
746
H.P
. x
746
E x
EF
F.
K.W
. x
1000
E
I x
E
1000
I x
E x
EF
F.
746
ALT
ER
NA
TIN
G C
UR
RE
NT
FERRAZ SHAWMUT
52
MOTOR OVERCURRENT PROTECTION
Overcurrent protection of motors is a threefold problem involvingnormal starting currents, stalled rotors, and running overloads.
Many motors draw starting currents several times their full-load rat-ings, and because of the transient nature of these currents noharm is done to the motors nor any part of the electrical system.
In most applications motors are selected which have a horsepowerrating equal to the power required by the application under normalconditions; and since motors are capable of carrying overloads forshort periods without excessive heating, a properly designed andselected overcurrent protective device makes this temporary over-load capacity available.
TRIPPING CHARACTERISTICS OF A CURRENT SENSITIVEDEVICE COMPARED WITH MOTOR CURRENT-TIME CURVE
The above chart shows the inverse-time characteristics of motorsand protective devices. When these curves coincide the entiremotor capacity becomes available. Whenever the protector curvemoves to the right of the motor curve the motor is inadequatelyprotected. A protector curve to the left gives a margin of safety.
Non time delay fuses have time-current curves which cross themotor curve, but time-delay fuses (such as Ferraz Amp-Trap 2000fuses or TRI-ONIC fuses) have characteristic curves which morenearly approximate the motor curve and when properly selectedboth protect the motor at all loads and make available most of themotor capacity.
t
FERRAZ SHAWMUT
53
IDENTIFICATION OF MOTORS
The National Electrical Code rules and the standards of the National ElectricalManufacturers Association require that all alternating current motors rated at 1/2horse power or larger, except polyphase wound-rotor motors, shall have thename-plate marked with a code letter to show its input in kilovolt-amperes withlocked rotor, selected from the following table:
Kilovolt-Amperes Kilovolt-Amperes Code per Horsepower Code per HorsepowerLetter with Locked Rotor Letter with Locked Rotor
A. . . . . . . . . . . . . 0 - 3.14 L . . . . . . . . . . . . . 9.0 - 9.99B . . . . . . . . . . . 3.15 - 3.54 M . . . . . . . . . . . 10.0 -11.19C. . . . . . . . . . . 3.55 - 3.99 N . . . . . . . . . . . 11.2 -12.49D. . . . . . . . . . . . 4.0 - 4.49 P . . . . . . . . . . . 12.5 -13.99E . . . . . . . . . . . . 4.5 - 4.99 R . . . . . . . . . . . 14.0 -15.99F . . . . . . . . . . . . 5.0 - 5.59 S . . . . . . . . . . . 16.0 -17.99G. . . . . . . . . . . . 5.6 - 6.29 T . . . . . . . . . . . 18.0 -19.99H. . . . . . . . . . . . 6.3 - 7.09 U . . . . . . . . . . . 20.0 -22.39J . . . . . . . . . . . . 7.1 - 7.99 V . . . . . . . . . . . 22.4 -and upK . . . . . . . . . . . . 8.0 - 8.99
Knowing the horsepower and voltage rating of any particular motor, its lockedrotor current may be determined from the “Locked KVA per Horsepower” by asimple formula which is:
For Single-phase MotorsLocked rotor current =
For Three-phase Motors
Locked rotor current =
For Two-phase Motors
Locked rotor current =
Example
Taking a 1/2 h.p., 220 volt, 3-phase motor with an “L” code letter
Locked rotor current = = 11.8 amperes (Minimum)
= 13.1 amperes (Maximum)
Therefore, the locked rotor current will be not less than 11.8 nor morethan 13.1 amperes.
(Locked KVA per h.p.) (rated h.p.) 1000
(rated voltage)
(Locked KVA per h.p.) (rated h.p.) 1000
(rated voltage) �3�
(Locked KVA per h.p.) (rated h.p.) 1000
(rated voltage) 2
9.0 x 1/2 x 1000
220 �3�9.99 x 1/2 x 1000
220 �3�
FERRAZ SHAWMUT
54
AVERAGE EFFICIENCY AND POWER FACTORVALUES OF MOTORS
APPROXIMATE LOCKED ROTOR CURRENTS OF3-PHASE SQUIRREL CAGE INDUCTION MOTORS
* Approx. 6 times the full-load currents shown on previous pages.** Approx. 8 times the full-load currents shown on previous pages.
When the actual efficiencies and power factors of the motors to be controlled arenot known, the following approximations may be used:
Efficiencies:D.C. motors, 35 horsepower and less 80% to 85%D.C. motors, above 35 horsepower 85% to 90%Synchronous motors (at 100% power factor) 92% to 95%
(“Apparent” efficiencies = Efficiency X power factor):Three phase induction motors, 25 horsepower and less 70%Three phase induction motors above 25 horsepower 80%
“High Efficiency” Three-Phase Motors:Induction motors, 20 horsepower and less 88% to 92%Induction motors, over 20 horsepower 93% to 95%
These figures may be decreased slightly for single-phase and two-phase induc-tion motors.
LOCKED ROTOR CURRENT IN AMPERESHP DESIGN B, C AND D MOTORS* HIGH EFFICIENCY MOTOR**
115V 208V 230V 460V 575V 115V 208V 230V 460V 575V1/23/41
1 1/2235
7 1/2101520253040506075100125150200
24.033.643.262.481.6
--------------------------------
13.218.624.034.245.063.6100145185277356449528686858102012701640206023803170
12.016.821.631.240.857.691.213216825232440848062478092411501490187021602880
6.008.4010.815.620.428.845.666.084.012616220424031239046257674493610801440
0.486.608.4012.616.223.436.654.066.01021321621922463123724625947508641150
32.044.857.683.2109--------------------------------
17.624.832.045.660.084.81341942463704755987049151140136016902180275031704220
16.022.428.841.654.476.81221762243364326446408321040123015401980250028803840
8.0011.214.420.827.238.460.888.0112168216272320416520616768992125014401920
0.648.8011.216.821.631.248.872.088.0136176216256328416496616792100011501540
FERRAZ SHAWMUT
55
DC MOTORS SINGLE PHASE AC MOTORS
HP 120V 240V 550V 115V 208V 230V
FULL LOAD CURRENT IN AMPERESFOR DC AND SINGLE PHASE AC MOTORS
1/61/41/31/23/41
1 1/2235
7 1/2101520253040506075100125150200
--3.14.15.47.69.513.21725405876------------------------
--1.62.02.73.84.76.68.512.2202938557289106140173206255341425506675
--------------------
12.21624313846617590111148185222294
4.45.87.29.813.8162024345680100------------------------
2.43.24.05.47.68.811
13.218.730.84455------------------------
2.22.93.64.96.98.0101217284050------------------------
FERRAZ SHAWMUT
56
TWO PHASE THREE PHASE
HP 115V 230V 460V 575V 115V 230V 460V 575V
FULL LOAD CURRENT IN AMPERESSQUIRREL CAGE MOTORS
1/23/41
1 1/2235
7 1/2101520253040506075100125150200
44.86.49.011.8
--------------------------------
2.02.43.24.55.98.313.219243647596990113133166218270312416
1.01.21.62.33.04.26.69.0121823293545566783109135156208
0.81.01.31.82.43.35.38.010141924283645536687108125167
4.46.48.412
13.6--------------------------------
2.53.24.26.06.89.615.2222842546880104130154192248312360480
1.11.62.13.03.44.87.611142127344052657796124156180240
0.91.31.72.42.73.96.19.011172227324152627799125144192
Synchronous Speed
rpm
18001200900720600450400360327277257
Multiplying
Factor
1.001.001.021.051.091.131.161.191.211.251.27
CURRENT CORRECTION FACTORSFOR LOW SPEED SQUIRREL CAGE MOTORS
FERRAZ SHAWMUT
57
AM
PE
RE
RA
TIN
GS
OF
SY
NC
HR
ON
OU
S M
OT
OR
S A
T F
UL
LL
OA
D(E
lect
ric
Mac
hin
ery
Mfg
. C
o.)
Am
pere
s gi
ven
belo
w a
re b
ased
on
aver
age
effic
ienc
y fo
r gi
ven
H.P
. at
all
spee
ds.
For
inst
ance
, 25
H.P
. am
pere
s ar
e ba
sed
on 8
7% E
ff. f
or a
llsp
eeds
and
100
0 H
.P.
on 9
5% E
ff. f
or a
ll sp
eeds
. F
or 8
0% P
.F.
ampe
res,
mul
tiply
100
% P
.F.
valu
es b
y 1.
29.
3-P
h. A
mp
eres
at
100%
P.F
.2-
Ph
. Am
per
es a
t 10
0% P
.F.
H.P
.
20 25 30 40 50 60 75 100
125
150
200
250
300
350
400
450
500
550
600
650
700
750
800
900
1000
Ass
um
edE
ffic
ien
cy
86.0
87.0
88
.089
.089
.590
.091
.091
.591
.592
.092
.092
.592
.593
.593
.593
.594
.094
.094
.094
.594
.594
.595
.095
.095
.0
220
V.
45.5
56 67 88 110
131
162
214
268
320
426
526
636
734
840
942
1045
1148
1250
1350
1450
1560
1660
1860
2060
440
V.
23 28 33.5
44 55 66 8110
713
416
021
326
331
837
242
047
152
357
462
567
572
578
083
093
010
30
550
V.
18.5
22.5
27 35 44 53 65 86 107
128
171
212
255
298
336
378
418
460
500
540
580
625
665
745
825
2200
V.
-- -- -- 9 11 13.1
16.2
21.4
27 32 43 53 64 74 84 9410
511
512
513
514
515
616
618
620
6
4000
V.
-- -- -- -- -- -- -- 12 15 17.5
24 29 35 41 46 52 58 63 69 75 80 86 91 102
113
220
V.
39.4
48.5
58 76.2
95.3
113.
514
018
523
227
736
945
555
063
572
781
590
399
210
8211
7012
5013
5014
4016
1017
80
440
V.
19.9
24.2
29 38.1
47.6
57.2
70 93 116
139
185
227
275
322
364
408
456
497
541
585
628
676
719
805
896
550
V.
16 19.5
23.4
30.6
38.1
45.9
56.3
74 93 111
148
184
221
258
291
327
362
398
433
468
502
541
576
645
715
2200
V.
4000
V.
-- -- -- -- -- -- --10
.413 15
.220
.825
.230
.335
.539
.845 50
.254
.659
.865 69 75 79 89 98
-- -- -- 7.8
9.5
11.4
14 18.5
23.4
27.8
37.3
46 55 64 73 81 90 100
110
117
125
135
144
161
178
FERRAZ SHAWMUT
58
Number of Revolutions per Minute When Frequency isPoles
Generator 25 30 40 50 60or Motor Cycles Cycles Cycles Cycles Cycles
SYNCHRONOUS SPEEDS - ALTERNATING CURRENTGENERATORS AND MOTORS
Frequency = Poles x R.P.M.
120
24681012141618202224262830323644485460687296100
1,50075050037530025021418816715013612511510710094837963565044423130
1,8009006004503603002572252001801641501381281201131008275666053503836
2,4001,200800600480400343300267240217200185171160150133109100908071675048
3,0001,5001,00075060050042837533330027325023121420018816613612511110088836460
3,6001,8001,2009007206005144504003603273002802572402252001641501331201061007572
SHAWMUT is one of the oldest names in fuses, but a SHAWMUT fuse is alwaysan up-to-date fuse, and always of the highest quality.
FERRAZ SHAWMUT
59
LOW VOLTAGE FUSES FOR MOTOR PROTECTION
OverloadProtection -Article 430 Part CCEC 28-2000The NEC and CECallow fuses to beused as the solemeans of overload protection for motorbranch circuits(oftenpractical with smallsingle-phase motors).If used, the fuseampere rating mustnot exceed the valueshown in this table.
Minimum Fuse provides both overload and short circuit protection per the NEC and CEC.This fuse rating eliminates the need for an overload relay, but nuisance fuseopening may occur if motor is fully loaded.
Typical Fuse sized near 150% motor FLA, used in conjunction with any overload relay.Heavy Load Maximum fuse size for effective short circuit protection. Not for code letter A motors.
Electrical Code RequirementsThe NEC and CEC require that motorbranch circuits be protected againstoverloads, by fuses, overload relays orthermal protectors and against shortcircuits by fuses or circuit breakers.
Maximum Fuse Ratingfor Overload Protection
*These percentages are not to be exceeded.
Motor Service Factoror marked
Temperature Rise
Service Factor of1.15 or greaterMarked Temp. Risenot exceeding 40°CAll others
Fuse Rating asa Percentage*of Motor FLA
125%
125%
115%
Full LoadAmperesat 115 V
MotorHP
MinimumRecommended Fuse Ampere Rating
230 Volt1 Phase
Class RK5
Cat No.TR(Amps)R
1.0 S.F. 1.15 S.F. TypicalHeavyLoad
Full LoadAmperesat 230 V
MotorHP
MinimumRecommended Fuse Ampere Rating
230 Volt1 Phase
Class RK5
Cat No.TR(Amps)R
1.0 S.F. 1.15 S.F. TypicalHeavyLoad
1/81/41/31/23/41
1 1/2235
7 1/210
2.22.93.64.96.9
8101217284050
2 1/23 2/10
45 6/10
89
1012
17 1/2304560
2 8/103 1/24 1/26 1/4
910121520355060
3 1/24 1/2
5 6/107
101215
17 1/225406075
45 6/10
79
1515
17 1/22530507090
1/81/41/31/23/41
1 1/2235
7 1/210
4.45.87.29,8
13.8162024345680
100
5 6/1079
1215
17 1/22025356090
110
5 6/108
1012
17 1/22025304070
100125
6 1/49
1215202530355080
125150
81215
17 1/22530354060
100150175
FU
SE
SE
LE
CT
ION
TA
BL
ES
FO
R S
HO
RT
CIR
CU
IT P
RO
TE
CT
ION
OF
230
VO
LT T
HR
EE
PH
AS
E M
OT
OR
S
Min
imu
m
Fus
es a
re s
ized
nea
r 12
5% o
f m
otor
ful
l loa
d cu
rren
t an
d m
ay n
ot c
oord
inat
e w
ith s
ome
NE
MA
20 o
verlo
ad r
elay
s.Ty
pic
al
S
ugge
sted
for
mos
t ap
plic
atio
ns.
Will
coo
rdin
ate
with
NE
MA
Cla
ss 2
0 ov
erlo
ad r
elay
s.H
eavy
Lo
ad
Not
app
licab
le f
or m
otor
s m
arke
d w
ith c
ode
lette
r A
.
FERRAZ SHAWMUT
60
Fu
llL
oad
Mo
tor
Am
per
esM
in.
Typ
ical
Hea
vyM
in.
Typ
ical
Hea
vyM
in.
Typ
ical
Hea
vyH
PA
t 46
0V2
Sec
s5
secs
> 5
Sec
s2
Sec
s5
Sec
s>
5 S
ecs
2 S
ecs
5 S
ecs
> 5
Sec
s
1/2
3/4 1
1 1/
22 3 5
71/2
10 15 20 25 30 40 50 60 75 100
125
150
200
2 8/
104 5 8 8 12 20 30 35 50 70 80 100
125
175
200
250
300
400
450
600
4 6 8 12 1217
1/2
30 40 50 80 100
125
150
200
250
300
350
450
600
600
--
3 1/
25
6 1/
49 10
17 1
/225 35 40 60 80 10
012
515
020
022
530
035
045
050
0--
3 4 5 8 8 12 20 30 35 50 70 80 100
125
175
200
250
300
400
450
600
4 6 8 12 1217
1/2
30 40 50 80 100
125
150
200
250
300
350
450
600
600
--
2.2
3.2
4.2
6.0
6.8
9.6
15.2
22 28 42 54 68 80 104
130
154
192
248
312
360
480
3 1/
25
6 1/
49 10 15 25 35 40 60 80 100
125
150
200
225
300
350
450
500
--
2 8/
10 4 5 8 8 12 20 30 35 50 70 80 100
125
175
200
250
300
400
450
600
4 6 8 12 12 15 30 40 50 80 100
125
150
200
250
300
350
450
600
600
--
3.5 5
6 1/
49 10 15 25 35 40 60 80 100
125
150
200
225
300
350
450
500
--
Rec
om
men
ded
Fu
se A
mp
ere
Rat
ing
Cla
ss R
K5
- T
RS
(Am
p)R
Cla
ss R
K1
- A
D2(
Am
p)R
Cla
ss J
- A
JT(A
mp
)
FERRAZ SHAWMUT
61
FU
SE
SE
LE
CT
ION
TA
BL
ES
FO
R S
HO
RT
CIR
CU
IT P
RO
TE
CT
ION
OF
460
VO
LT T
HR
EE
PH
AS
E M
OT
OR
S
Min
imu
m
Fus
es a
re s
ized
nea
r 12
5% o
f m
otor
ful
l loa
d cu
rren
t an
d m
ay n
ot c
oord
inat
e w
ith s
ome
NE
MA
20 o
verlo
ad r
elay
s.Ty
pic
al
S
ugge
sted
for
mos
t ap
plic
atio
ns.
Will
coo
rdin
ate
with
NE
MA
Cla
ss 2
0 ov
erlo
ad r
elay
s.H
eavy
Lo
ad
Not
app
licab
le f
or m
otor
s m
arke
d w
ith c
ode
lette
r A
.
Fu
llL
oad
Mo
tor
Am
per
esM
in.
Typ
ical
Hea
vyM
in.
Typ
ical
Hea
vyM
in.
Typ
ical
Hea
vyH
PA
t 46
0V2
Sec
s5
secs
> 5
Sec
s2
Sec
s5
Sec
s>
5 S
ecs
2 S
ecs
5 S
ecs
> 5
Sec
s
1/2
3/4 1
1 1/
22 3 5
71/2
10 15 20 25 30 40 50 60 75 100
125
150
200
250
300
400
500
1 4/
102
2 1/
23
1/2
45
6/10
10 1517
1/2
25 35 40 50 70 80 100
125
175
200
225
300
400
450
-- --
22
8/10
45
6/10
6 9 15 20 25 40 50 60 70 100
125
150
175
225
300
350
450
600
-- -- --
1.6
2 1/
43
2/10
4 1/
25 7 12
17 1
/220 30 40 50 60 80 10
012
515
020
022
525
035
045
060
0-- --
1.5 2 2.5
3.5 4 6 10 15
17 1
/225 35 40 50 70 80 10
012
517
520
022
530
040
045
0-- --
22
8/10
4 5.6 6 9 15 20 25 40 50 60 70 100
125
150
175
225
300
350
450
600
-- -- --
1.1
1.6
2.1 3 3.4
4.8
7.6
11 14 21 27 34 40 52 65 77 96 124
156
180
240
300
360
480
600
1.6
2 1/
43
2/10
4 1/
25 7 12
17 1
/220 30 40 50 60 80 10
012
515
020
022
525
035
045
060
0-- --
1 4/
102 2.5
3.5 4
5 6/
1010 15
17 1
/225 35 40 50 70 80 10
012
517
520
022
530
040
045
0-- --
2 2.8 4 5.6 6 9 15 20 25 40 50 60 70 100
125
150
175
225
300
350
450
600
-- -- --
1.6
2 1/
43
2/10
4 1/
25 8 12
17 1
/220 30 40 50 60 80 10
012
515
020
022
525
035
045
060
0-- --
Rec
om
men
ded
Fu
se A
mp
ere
Rat
ing
Cla
ss R
K5
- T
RS
(Am
p)R
*C
lass
RK
1 -
A6D
(Am
p)R
Cla
ss J
- A
JT(A
mp
)
FERRAZ SHAWMUT
62
FU
SE
SE
LE
CT
ION
TA
BL
ES
FO
R S
HO
RT
CIR
CU
IT P
RO
TE
CT
ION
OF
575
VO
LT T
HR
EE
PH
AS
E M
OT
OR
S
Min
imu
m
Fus
es a
re s
ized
nea
r 12
5% o
f m
otor
ful
l loa
d cu
rren
t an
d m
ay n
ot c
oord
inat
e w
ith s
ome
NE
MA
20 o
verlo
ad r
elay
s.Ty
pic
al
S
ugge
sted
for
mos
t ap
plic
atio
ns.
Will
coo
rdin
ate
with
NE
MA
Cla
ss 2
0 ov
erlo
ad r
elay
s.H
eavy
Lo
ad
Not
app
licab
le f
or m
otor
s m
arke
d w
ith c
ode
lette
r A
.
Fu
llL
oad
Mo
tor
Am
per
esM
in.
Typ
ical
Hea
vyM
in.
Typ
ical
Hea
vyM
in.
Typ
ical
Hea
vyH
PA
t 57
5V2
Sec
s5
Sec
s>
5 S
ecs
2 S
ecs
5 S
ecs
> 5
Sec
s2
Sec
s5
Sec
s >
5 S
ecs
1/2
3/4 1
1 1/
22 3 5
71/2
10 15 20 25 30 40 50 60 75 100
125
150
200
250
300
400
500
1 1/
81
6/10
2 1/
43
3 2/
105 8 12 15 20 30 35 40 50 70 75 100
125
150
175
250
300
350
-- --
1 6/
102
1/2
3 4
1/2
5 7 1217
1/2
20 30 40 50 60 75 100
110
150
175
225
300
350
500
600
-- --
1 4/
102
2 1/
23
1/2
4 6 9 1517
1/2
25 35 40 50 60 80 90 125
150
200
225
300
350
450
-- --
1 1/
81
6/10
2 1/
43
3 2/
10 5 8 12 15 20 30 35 40 50 70 80 100
125
150
175
250
350
350
-- --
1 6/
102
1/2
34
1/2
5 7 1217
1/2
20 30 40 50 60 75 100
110
150
175
225
300
350
500
600
-- --
.9 1.3
1.7
2.4
2.7
3.9
6.1 9 11 17 22 27 32 41 52 62 77 99 125
144
192
240
289
382
472
1 4/
102
2 1/
23
1/2
4 6 9 1517
1/2
25 35 40 50 60 80 90 125
150
175
225
300
350
450
-- --
1.12
51
6/10
2.5 3
3 2/
105 8 12 15 20 30 35 40 50 70 75 100
125
150
175
250
300
350
-- --
1 6/
102
1/2
3 4
1/2
5 7 1217
1/2
20 30 40 50 60 75 100
110
150
175
225
300
350
500
600
-- --
1 4/
102
2 1/
23
1/2
4 6 10 1517
1/2
25 35 40 50 60 80 90 125
150
200
225
300
400
450
-- --
Rec
om
men
ded
Fu
se A
mp
ere
Rat
ing
Cla
ss R
K5
- T
RS
(Am
p)R
*C
lass
RK
1 -
A6D
(Am
p)R
Cla
ss J
- A
JT(A
mp
)
5101520253550607590100125150200300400500750
1,000
4080120160200280400480600720800
1,0001,2001,6002,4003,2004,0006,0008,000
20406080100140200240300360400500600800
1,2001,6002,0003,0004,000
102030405070100120150180200250300400600800
1,0001,5002,000
77.082.082.584.085.087.088.088.588.588.589.090.590.591.091.391.891.892.092.5
81.085.086.586.588.089.089.590.590.590.590.591.091.391.591.892.392.292.393.0
82.586.086.587.589.089.590.591.091.091.091.091.091.592.092.092.592.592.593.5
FERRAZ SHAWMUT
63
Kilowatts Output Current Amperes Efficiency %
Capacity 125 Volts 250 Volts 500 Volts 1/2 Load 3/4 Load Full Load
FIELD CURRENT IN D.C. GENERATORS
It has been found that a fair average for the field amperes of different sized generators is as follows:
K.W. ................1 5 10 20 30 50 75 100Percent ............8 6 5 4 3.5 3 3 2.75
The field current, expressed as a percentage of full load current on lines, isdetermined with all of the resistance out.
D.C. GENERATORS
Application of Power Factor Capacitators
Power factor capacitors can be connected across electric lines to neutralize theeffect of lagging power-factor loads, thereby reducing the current drawn for agiven kilowatt load. In a distribution system, small capacitor units may be connected at the individual loads or the total capacitor kilovolt-amperes may begrouped at one point and connected to the main. Although the total kvar of capacitors is the same, the use of small capacitors at the individual loadsreduces current all the way from the loads back to the source and thereby hasgreater PF corrective effect than the one big unit on the main, which reducescurrent only from its point of installation back to the source.
Calculating Size of Capacitor:
Assume it is desired to improve the power factor a given amount by the additionof the capacitors to the circuit.
Then kvarR = kw x (tan �1 - tan �2)
where kvarR = Rating of required capacitorkvar1 = reactive kilovolt-amperes at original PFkvar2 = reactive kilovolt-amperes at improved PF
�1 = original phase angle�2 = phase angle at improved PF
kw = load at which original PF was determined
NOTE: The phase angle �1 and �2 can be determined from a table of trigono-metric functions using the following relationships:
�1 = The angle which has its cosine equal to the decimal value ofthe original power factor.(eg. 0.70 for 70% PF; 0.65 for 65%PF, etc.)
�2 = The angle which has its cosine equal to the decimal value ofthe improved power factor.
-Electrical Construction and Maintenance Magazine
FERRAZ SHAWMUT
64
FERRAZ SHAWMUT
65
TABLE FOR CALCULATING NECESSARY CAPACITOR
Desired Power Factor in Percentage
505152
535455
565758
596061
626364
656667
686970
717273
747576
777879
808182
838485
80.982.936.894
.850
.809
.769
.730
.692
.655
.618
.584
.549
.515
.483
.450
.419
.388
.358
.329
.209
.270
.242
.213
.186
.159
.132
.105
.079
.053
.026
.000----
------
811.008.962.920
.876
.835
.795
.756
.718
.681
.644
.610
.575
.541
.509
.476
.445
.414
.384
.355
.325
.296
.268
.239
.212
.185
.158
.131
.105
.079
.052
.026
.000--
------
821.034.988.946
.902
.861
.821
.782
.744
.707
.670
.636
.601
.567
.535
.502
.471
.440
.410
.381
.351
.322
.294
.265
.238
.211
.184
.157
.131
.105
.078
.052
.026
.000
------
831.0601.014.972
.928
.887
.847
.808
.770
.733
.696
.662
.627
.593
.561
.528
.497
.466
.436
.407
.377
.348
.320
.291
.264
.237
.210
.183
.157
.131
.104
.078
.052
.026
.000----
841.0861.040.998
.954
.913
.873
.834
.796
.759
.722
.688
.653
.619
.587
.554
.523
.492
.462
.433
.403
.374
.346
.317
.290
.263
.236
.209
.183
.157
.130
.104
.078
.052
.026
.000--
851.1121.0661.024
.980
.939
.899
.860
.822
.785
.748
.714
.679
.645
.613
.580
.549
.518
.488
.459
.429
.400
.372
.343
.316
.289
.262
.235
.209
.183
.156
.130
.104
.078
.052
.026
.000
861.1391.0931.041
1.007.966.926
.887
.849
.812
.775
.741
.706
.672
.640
.607
.576
.545
.515
.486
.456
.427
.399
.370
.343
.316
.289
.262
.236
.210
.183
.157
.131
.105
.079
.053
.027
871.1651.1191.077
1.033.992.952
.913
.875
.838
.801
.767
.732
.698
.666
.633
.602
.571
.541
.512
.482
.453
.425
.396
.369
.342
.315
.288
.262
.236
.209
.183
.157
.131
.105
.079
.053
881.1921.1461.104
1.0601.019.979
.940
.902
.865
.828
.794
.759
.725
.693
.660
.629
.598
.568
.539
.509
.480
.452
.423
.396
.369
.342
.315
.289
.263
.236
.210
.184
.158
.132
.106
.080
891.2201.1741.132
1.0881.0471.007
.968
.930
.893
.856
.822
.787
.753
.721
.688
.657
.626
.596
.567
.537
.508
.480
.451
.424
.397
.370
.343
.317
.291
.264
.238
.212
.186
.160
.134
.108
Example: Total kw input of plant from wattmeter reading 100 kw at powerfactor of 60%. The leading reactive kva, necessary to raise the power factor
901.2481.2021.160
1.1161.0751.035
.996
.958
.921
.884
.849
.815
.781
.749
.716
.685
.654
.624
.595
.565
.536
.508
.479
.452
.425
.398
.371
.345
.319
.292
.266
.240
.214
.188
.162
.136
911.2761.2301.188
1.1441.1031.063
1.024.986.949
.912
.878
.843
.809
.777
.744
.713
.682
.652
.623
.593
.564
.536
.507
.480
.453
.426
.399
.373
.347
.320
.294
.268
.242
.216
.190
.164
921.3031.2571.215
1.1711.1301.090
1.0511.013.976
.939
.905
.870
.836
.804
.771
.740
.709
.679
.650
.620
.591
.563
.534
.507
.480
.453
.426
.400
.374
.347
.321
.295
.269
.243
.217
.191
931.3371.2911.249
1.2051.1641.124
1.0851.0471.010
.973
.939
.904
.870
.838
.805
.774
.743
.713
.684
.654
.625
.597
.568
.541
.514
.487
.460
.434
.408
.381
.355
.329
.303
.277
.251
.225
941.3691.3231.281
1.2371.1961.156
1.1171.0791.042
1.005.971.936
.902
.870
.837
.806
.775
.745
.716
.686
.657
.629
.600
.573
.546
.519
.492
.466
.440
.413
.387
.361
.335
.309
.283
.257
951.4031.3571.315
1.2711.2301.190
1.1511.1131.076
1.0391.005.970
.936
.904
.871
.840
.809
.779
.750
.720
.691
.663
.634
.607
.580
.553
.526
.500
.474
.447
.421
.395
.369
.343
.317
.291
961.4411.3951.353
1.3091.2681.228
1.1891.1511.114
1.0771.0431.008
.974
.942
.909
.878
.847
.817
.788
.758
.729
.701
.672
.645
.618
.591
.564
.538
.512
.485
.459
.433
.407
.381
.355
.329
971.4811.4351.393
1.3491.3081.268
1.2291.1911.154
1.1171.0831.048
1.014.982.949
.918
.887
.857
.828
.798
.769
.741
.712
.685
.658
.631
.604
.578
.552
.525
.499
.473
.447
.421
.395
.369
981.5291.4831.441
1.3971.3561.316
1.2771.2391.202
1.1651.1311.096
1.0621.030.997
.966
.935
.905
.876
.840
.811
.783
.754
.727
.700
.673
.652
.620
.594
.567
.541
.515
.489
.463
.437
.417
991.5901.5441.502
1.4581.4171.377
1.3381.3001.263
1.2261.1921.157
1.1231.0911.058
1.027.996.966
.937
.907
.878
.850
.821
.794
.767
.740
.713
.687
.661
.634
.608
.582
.556
.530
.504
.478
1001.7321.6861.644
1.6001.5591.519
1.4801.4421.405
1.3681.3341.299
1.2651.2331.200
1.1691.1381.108
1.0791.0491.020
.992
.963
.936
.909
.882
.855
.829
.803
.776
.750
.724
.698
.672
.645
.620
KVA TO CORRECT LOAD TO DESIRED POWER FACTOR(Cornell Dubilier)
Desired Power Factor in Percentage
to 90% is found by multiplying the 100 kw by the factor found in the table,which is .849. Then 100 kw x 0.849 = 84.9 kva. Use 85 kva.
FERRAZ SHAWMUT
66
505152
535455
565758
596061
626364
656667
686970
717273
747576
777879
808182
838485
Exi
stin
g P
ow
er F
acto
r
FERRAZ SHAWMUT
67
TRANSFORMER PROTECTION
Article 450-3 of the National Electrical Code and Rule 26-254 of the CanadianElectrical Code cover overcurrent protection of transformers. Some of therequirements are summarized here.
Transformers - Primary 600 Volts or LessIf secondary fuse protection is not provided, primary fuses are to be selectedaccording to Table 1. If both primary and secondary fuses are used, they are tobe selected according to Table 2.
Table 1 - Primary Fuse Only
* May be increased to next higher std. fuse size.
Table 2 - Primary and Secondary Fuses
*May be increased to next higher std. fuse size
Transformer Magnetizing Inrush CurrentsWhen voltage is switched on to energize a transformer, the transformer corenormally saturates. This results in a large inrush (magnetizing) current which isgreatest during the first half cycle (approx. .01 second) and becomes progres-sively less severe over the next several cycles (approx. 0.1 second) until thetransformer reaches its normal magnetizing current.
To accommodate this inrush current, fuses are often selected which have time-current withstand values of at least 12 times transformer primary rated current for0.1 second and 25 times for 0.01 second. Recommended primary fuses forpopular, low-voltage 3-phase transformers are shown on the next page. Controlcircuit transformers may have substantially greater inrush currents. For theseapplications, the fuse should be selected to withstand 40 times transformerprimary rated current for 0.01 second.
Transformer Maximum % Rating
Secondary Primary
Amperes Fuse Secondary
NEC CEC Fuse
9 or More 250 300 125*
Less than 9 250 300 167
Transformer MaximumPrimary Primary Fuse
Amperes % Rating
9 or More 125* (NEC) / 150* (CEC)
2 to 9 167
Less than 2 300
FERRAZ SHAWMUT
68
SECONDARY FUSES
Selecting fuses for the secondary is simple once rated secondary current isknown. Fuses are sized at 125% secondary FLA or next higher rating of at167% of secondary FLA depending on secondary current. (See NEC and CECguidelines on pervious page). The preferred sizing is 125% of rated secondaryIcurrent (Isec) or next higher fuse rating. Determine transformer rating (VA orkVA), secondary voltage (Vsec) and whether it is single or three phase.
1. Single Phase: Isec = or
2. Three Phase: Isec = or
When Isec is determined, multiply it by 1.25 and choose that fuse rating or thenext higher rating. (Isec x 1.25 = Fuse Rating).For transformers with primary over 600 volts, consult the Application Section inthe Ferraz Shawmut Advisor.
RECOMMENDED PRIMARY FUSES FOR 240 VOLTTHREE PHASE TRANSFORMERS
* When using these fuses, transformer secondary must also be fused to comply withNEC 450-3 and CEC 26-254.
Trans- Primary Fuse Ratingformer Primary
Rating Full Load AJT* orKVA Amps TR-R A2D-R* A4BQ* A4BY* A4BT*
35
7 1/2915304575100
112.515022530050075010001500
7.212182236721081802412713615417221203180424063608
91525304590150225300350450600----------
1525404560150225400450500600------------
----------------------
12001600250040005000
--
----------------------
90012002000300050006000
----------------------
80012001800
------
Transformer VAVsec
Transformer KVA x 1000Vsec
Transformer VA1.73 x Vsec
Transformer KVA x 10001.73 Vsec
FERRAZ SHAWMUT
69
* When using these fuses, transformer secondary must also be fused to comply withNEC 450-3 and CEC 26-254.
Trans- Primary Fuse Ratingformer PrimaryRating Full Load AJT* orKVA Amps TRS-R A6D-R* A4BQ* A4BY* A4BT*
3
5
7 1/2
9
15
30
45
75
100
112.5
150
225
300
500
750
1000
1500
2000
2500
3.6
6.0
9.0
11
18
36
54
90
120
135
180
271
361
601
902
1203
1804
2406
3007
4 1/2
8
12
15
25
45
70
125
150
175
225
350
450
--
--
--
--
--
--
6
12
15
25
35
60
100
175
225
300
400
500
600
--
--
--
--
--
--
--
--
--
--
--
--
--
--
--
--
--
--
--
1200
2000
2500
4000
5000
6000
--
--
--
--
--
--
--
--
--
--
--
--
--
1000
1600
2000
3000
4000
5000
--
--
--
--
--
--
--
--
--
--
--
--
--
1000
1400
1800
--
--
--
RECOMMENDED PRIMARY FUSES FOR 480 VOLTTHREE PHASE TRANSFORMERS
FERRAZ SHAWMUT
70
* When using these fuses, transformer secondary must also be fused to comply withNEC 450-3 and CEC 26-254.
Trans- Primary Fuse Ratingformer PrimaryRating Full Load AJT* orKVA Amps TRS-R A6D-R* A4BQ* A4BY* A4BT*
3
5
7 1/2
9
15
30
45
75
100
112.5
150
225
300
500
750
1000
1500
2000
2500
2.9
4.8
7.2
9
14
29
43
72
96
108
144
217
289
481
722
962
1443
1925
2406
4
6
9
12
20
35
60
90
125
150
200
300
350
600
--
--
--
--
--
5
10
15
17 1/2
25
45
80
150
200
225
300
450
500
--
--
--
--
--
--
--
--
--
--
--
--
--
--
--
--
--
--
--
1000
1600
2000
3000
4000
5000
--
--
--
--
--
--
--
--
--
--
--
--
--
900
1400
1800
2500
4000
5000
--
--
--
--
--
--
--
--
--
--
--
--
--
700
1200
1600
2000
--
--
RECOMMENDED PRIMARY FUSES FOR 600 VOLTTHREE PHASE TRANSFORMERS
FERRAZ SHAWMUT
71
CONTROL CIRCUIT TRANSFORMERS
Control circuit transformers used as part of a motor control circuitare to be protected as outlined in NEC 450-3 and CEC 25-256with one important exception. The NEC allows primary fuses to besized up to 500% of transformer rated primary current if the ratedcurrent is less than 2 amperes.
When a control circuit transformer is energized, the typicalmagnetizing inrush will be 25-40 times rated primary full loadcurrent (FLA) for the first 1/2 cycle and dissipates to rated currentin a few cycles. Fuses must be sized so they do not open duringthis inrush. We recommend that fuses be selected to withstand40 x FLA for 0.01 second and to stay within the guidelinesspecified above.
For example: 300VA Transformer, 600V primary
Ipri = = = 1/2A
The fuse time-current curve must lie to the right of the point40 x (1/2A) = 20A @ .01 second.
RECOMMENDED ATQR CLASS CC PRIMARY FUSESFOR SINGLE PHASE CONTROL TRANSFORMERS
Trans- 240V Primary 480V Primary 600V Primaryformer
VA Pri. FLA ATQR Pri. FLA ATQR Pri. FLA ATQR
5075100130150200250500750100015002000
0.210.310.420.540.630.831.042.083.134.166.25
--
4/101/26/10
11
1 1/224*7*10*10--
0.100.160.210.270.310.420.521.041.562.083.134.17
1/43/104/101/21/26/108/10
234*7*10*
0.080.130.170.220.250.330.420.831.251.672.503.33
1/41/43/100.41/21/26/101 1/22 1/2
35*8*
* When using these fuses, transformer secondary must also be fused to comply with NEC 450-3and CEC 26-256.
Transformer VA 300 Primary V 600
FERRAZ SHAWMUT
72
CONVERSION FACTORS - KVA TO AMPERES
Three-Phase Amperes per Two-wire VoltsVolts Phase Amperes per
Line-to-line per kVA AC DC per kVA or KW
110115120180199--
208220230240416440--
460480550575600--------
5.255.024.813.212.90
--2.782.632.512.411.391.31
--1.251.201.051.000.96
--------
100--
115120--
220--
230240250265--
277----
416440460480550575600
--110115--
125--------
250--
275--
300----------
550--
600
10.09.108.708.338.004.55
--4.354.174.003.773.643.613.33
--2.412.272.172.081.821.741.67
For example, determine the necessary busway rating to carry the full currentfrom a 750 kVA, 3-phase transformer at 220 volts. From the table, one kVA at220 volts is 2.63 amp per phase. Hence, the full-load current is 2.63 times 750or 1972.5 amp per phase, requiring, at the minimum, a 2000 amp, 3-phase, 3-conductor feeder busway.
When you need fuses for any purpose, always ask about the latest SHAWMUTfuse for that purpose. SHAWMUT engineering is never satisfied with merelymaking better product; it is alert at all times to the most exacting requirementsof circuit protection and consequently to the most exacting requirements forfuses.
How to convert kVA to amperes.
FERRAZ SHAWMUT
73
AMPERES FOR ONE KW AT VARIOUS VOLTAGESAND POWER FACTORS
SINGLE-PHASE CIRCUITS
Amperes per Kilowatt
@ Power Factor
Volts 100% 90% 80% 70% 60% 50%
115
230
460
575
2300
8.70
4.38
2.17
1.74
0.435
9.67
4.87
2.41
1.93
0.483
10.9
5.48
2.71
2.18
0.544
12.4
6.23
3.10
2.49
0.621
14.5
7.30
3.62
2.90
0.725
17.4
8.76
4.34
3.48
0.870
TWO-PHASE CIRCUITS
Amperes per Kilowatt
@ Power Factor
Volts 100% 90% 80% 70% 60% 50%
115
230
460
575
2300
4.35
2.17
1.09
0.870
0.217
4.83
2.41
1.21
0.966
0.242
5.44
2.71
1.36
1.09
0.271
6.21
3.10
1.56
1.24
0.310
7.25
3.62
1.82
1.45
0.362
8.70
4.34
2.18
1.74
0.434
THREE-PHASE CIRCUITS
Amperes per Kilowatt
@ Power Factor
Volts 100% 90% 80% 70% 60% 50%
115
208
230
460
575
2400
4160
7200
5.02
2.78
2.51
1.26
1.00
0.241
0.139
.0802
5.58
3.08
2.79
1.39
1.12
0.268
0.154
.0891
6.28
3.48
3.18
1.58
1.25
0.301
0.174
0.100
7.17
3.97
3.59
1.80
1.43
0.344
0.199
0.115
8.37
4.63
4.18
2.10
1.67
0.402
0.232
0.134
10.0
5.56
5.02
2.52
2.00
0.482
0.278
0.160
FERRAZ SHAWMUT
74
Three single-phase transformersconnected delta-delta ina three-phase system
Three single-phase transformersconnected star-star ina three-phase system
FERRAZ SHAWMUT
75
Three single-phase transformersconnected delta-star ina three-phase system
Three single-phase transformersconnected star-delta ina three-phase system
Two single-phase transformersconnected open delta in a three phase
systemTwo single-phase transformersconnected star in a four-wire
two-phase system
FERRAZ SHAWMUT
76
Two single-phase transformersconnected in a three-wire
two-phase system
Two single-phase transformersconnected in a three phase
two-phase system. Scott Connection
GRAPHIC SYMBOLS FOR ELECTRICAL WIRINGLighting outlets
Outlet
Blanked Outlet
Junction Box
Lamp Fixture Holder
Recessed Lamp Fixture
Drop Cord
Recessed Exit Light
Surface or Pendant Exit Light
Surface or Pendant Fluorescent Fixture
Recessed Fluorescent Fixture
Surface/Pendant Continuous-Row Fluorescent Fixture
Recessed Continuous -Row Fluorescent Fixture
Bare-Lamp Fluorescent Strip
Receptacle Outlets
Single Receptacle Outlet
Duplex Receptacle Outlet
Switched Receptacle & Convenience Outlet
Duplex Receptacle Outlet - Split Wired
Single Special-Purpose Receptacle Outlet
Special-Purpose Connection - Subscript LettersIndicate Function (DW - Dishwasher, etc.)
Floor Receptacle
Clock Hanger Receptacle
Fan Hanger Receptacle
Floor Duplex Receptacle Outlet
Floor Telephone Outlet - Public
FERRAZ SHAWMUT
77
FERRAZ SHAWMUT
78
APPROXIMATE COST OF OPERATING AVERAGEELECTRICAL APPLIANCES ON A 10-CENT RATE
Note - For different rates,multiply the new rate times the annual usage. Example: The annualcost of running a hot water heater at $.08/KWH would be .08 x 4000 = $320.00
Source: Massachusetts Electric Company
FERRAZ SHAWMUT
79
Hot Water Heater 4,000 $400.00Air Conditioner (Room) 300 30.00Air Conditioner (House) 1,300 130.00Swimming Pool 1,900 190.00Room Heater 720 72.00Refrigerator: Manual (12 Cu. Ft.) 600 60.00
Automatic Defrost (14 Cu. Ft.) 950 95.00Automatic Defrost (19 Cu. Ft.) 1,400 140.00
Freezer: Manual (16 Cu. Ft.) 950 95.00Automatic Defrost (16 Cu. Ft.) 1,100 110.00
Water Bed 1,000 100.00Lighting: 4 - 5 Rooms 550 55.00
6 - 8 Rooms 670 67.009 - 12 Rooms 1,300 130.00
Attic Fan 375 37.50Clothes Dryer 1,000 100.00Furnace Fan 400 40.00Range/Oven 460 46.00Well Pump 500 50.00Dishwasher (Not Incl. Hot Water 360 36.00Dehumidifier 540 54.00Window Fan 300 30.00Colour Television 300 30.00Microwave Oven 250 25.00Sump Pump 240 24.00Toaster Oven 160 16.00Personal Computer 160 16.00Coffee Maker 120 12.00Slow Cooker 120 12.00Frying Pan 120 12.00Washing Machine (Not Hot Water) 150 15.00Iron 110 11.00Electric Blanket 100 10.00Black & White Television 85 8.50Stereo 85 8.50Radio 85 8.50Broiler 70 7.00Trash Compactor 70 7.00Vacuum Cleaner 35 3.50Toaster 25 2.50Sandwich Grill 25 2.50
Appliance
Typical AverageAnnual Power
Consumption - KWHAnnual Cost at10 Cents/KWH
FERRAZ SHAWMUT
80
THERMOMETER SCALECelsius - Fahrenheit
Celsius = 5/9 (F - 32) Fahrenheit = 9/5 C + 32C F C F C F C F
-35
-30
-25
-20
-19
-18
-17
-16
-15
-14
-13
-12
-11
-10
-9
-8
-7
-6
-5
-4
-3
-2
-1
0
1
2
3
4
5
6
7
8
9
10
11
12
-31.0
-22.0
-13.0
-4.0
-2.2
-.4
1.4
3.2
5.0
6.8
8.6
10.4
12.2
14.0
15.8
17.6
19.4
21.2
23.0
24.8
26.6
28.4
30.2
32.0
33.8
35.6
37.4
39.2
41.0
42.8
44.6
46.4
48.2
50.0
51.8
53.6
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
55.4
57.2
59.0
60.8
62.6
64.4
66.2
68.0
69.8
71.6
73.4
75.2
77.0
78.8
80.6
82.4
84.2
86.0
87.8
89.6
91.4
93.2
95.0
96.8
98.6
100.4
102.2
104.0
105.8
107.6
109.4
111.2
113.0
114.8
116.0
118.4
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
120.2
122.0
123.8
125.6
127.4
129.2
131.0
132.8
134.6
136.4
138.2
140.0
141.8
143.6
145.4
147.2
149.0
150.8
152.6
154.4
156.2
158.0
159.8
161.6
163.4
165.2
167.0
168.8
170.6
172.4
174.2
176.0
177.8
179.6
181.4
183.2
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
105
110
115
120
130
140
150
160
170
180
190
200
250
300
350
400
500
600
800
1000
185.0
186.8
188.6
190.4
192.2
194.0
195.8
197.6
199.4
201.2
203.0
204.8
206.6
208.4
210.2
212.0
221.0
230.0
239.0
248.0
266.0
284.0
302.0
320.0
338.0
356.0
374.0
392.0
482.0
572.0
662.0
752.0
932.0
1112.0
1472.0
1832.0
FERRAZ SHAWMUT
81
GENERAL CONVERSION TABLE
BTU x 777.5 = Foot poundsBTU x 1055 = JoulesBTU x 0.000293 = Kilowatt hoursBTU per minute x 13.0 = Foot pounds per secondBTU per minute x 0.0176 = KilowattsBTU per hour x 0.000293 = KilowattsCubic feet x 0.02832 = Cubic metersCubic feet per minute x 7.48 = US Gallons per minuteCubic inches x 16.387 = Cubic centimetersCycles per second = HertzDegrees x 0.01745 = RadiansDegrees Celsius x 1.8 + 32 = Degrees FahrenheitDegrees Celsius = (Degrees Fahrenheit - 32) ÷ 1.8Feet x 30.48 = CentimetersFeet x 0.3048 = MetersFeet of water x 0.883 = Inches of MercuryFeet of water X 63.43 = Pounds per square footFeet of water X 0.43135 = Pounds per square inchFeet per minute X 0.0114 = Miles per hourFeet per second x 0.682 = Miles per hourFeet per second x 0.3048 = Meters per secondFoot-pounds x 0.0229 = BTUFoot-pounds x 5.05/10,000,000 = Horsepower hoursFoot-pounds x 3.77/10,000,000 = Kilowatt hoursFoot-pounds x 1.356 = JoulesFoot-pounds x 1.356 = Newton metersFoot-pounds per minute x 0.00129 = BTU per minuteFoot-pounds per minute x 3.03/100,000 = HorsepowerFoot-pounds per second x 0.00182 = HorsepowerFoot-pounds per second x 1.356 = WattsGallons (US) x 3.785 = LitersGallons (US) x 0.134 = Cubic feetGallons (Imperial) x 1.2 = US GallonsHorsepower x 746 = WattsHorsepower x 42.4 = BTU per minuteHorsepower x 33,000 = Foot-pounds per minuteHorsepower x 550 = Foot-pounds per second
FERRAZ SHAWMUT
82
GENERAL CONVERSION TABLE CONT.
Horsepower Boiler x 33,520 = BTU per hourHorsepower Boiler x 9.80 = KilowattsHorsepower hours x 2550 = BTUHorsepower hours X 1,980,000 = Foot-poundsInches x 2.54 = CentimetersInches of mercury x 1.133 = feet of waterInches of mercury x 70.7 = Pounds per square footInches of mercury x 0.491 = Pounds per square inchInches of mercury x 3.374 = KilopascalsInches of water x 0.0735 = Inches of MercuryInches of water x 5.2 = Pounds per square footInches of water x 0.2486 = KilopascalsInch pounds x 0.1130 = Newton metersKilowatts x 56.9 = BTU per minuteKilowatts x 3412 = BTU per hourKilowatts x 1.341 = HorsepowerKilowatt hours x 3412 = BTUKilowatt hours x 1.34 = Horsepower hoursMiles per hour x 1.47 = Feet per secondMiles per hour x 0.447 = Meters per secondMiles per hour x 1.609 = Kilometers per hourMinutes x 0.000291 = RadiansPounds mass x 0.4536 = KilogramsPounds force x 4.448 = NewtonsPounds per cubic foot x 16.02 = Kilograms per cubic meterPounds per cubic foot x 16.02 = Grams per literPounds per square foot x 0.016 = Feet of waterPounds per square inch x 2.31 = Feet of waterPounds per square inch x 144 = pounds per square footPounds per square inch x 6.895 = KilopascalsRadians x 57.3 = DegreesRadians x 3438 = MinutesRevolutions x 6.28 = RadiansRevolutions per minute x 0.105 = Radians per secondSquare inches x 1,273,000 Circular MillsSquare inches x 6.452 = Square centimetersSquare feet x 0.0929 = Square meters
FERRAZ SHAWMUT
83
WEIGHTS AND MEASURES
Troy Weight24 grains = 1 penny weight 12 ounces = 1 pound20 pennyweights = 1 ounce 3.168 grains = 1 carat
Used for weighing gold, silver and jewels
Apothecaries’ Weight20 grains = 1 scruple 8 drams = 1 ounce3 scruples = 1 dram 12 ounces = 1 pound
The ounce and pound in this are the same as in Troy weight
Avoirdupois Weight27-11/32 grains = 1 dram 4 quarters = 1 hundredweight16 drams = 1 ounce 2000 pounds = 1 short ton16 ounces = 1 pound 2240 pounds = 1 long ton25 pounds = 1 quarter
Dry Measure2 pints = 1 quart 4 pecks = 1 bushel8 quarts = 1 peck 36 bushels = 1 chaldron
Liquid Measure
4 gills = 1 pint 31-1/2 gallons = 1 barrel2 pints = 1 quart 2 barrels = 1 hogshead4 quarts = 1 gallon 1 gallon = 231 cubic inches
Mariners’ Measure6 feet = 1 fathom 5280 feet = 1 statute mile120 fathoms = 1 cable length 6086 feet = 1 nautical mile7-1/2 cable lengths = 1 mile
Miscellaneous3 inches = 1 palm 18 inches = 1 cubit4 inches = 1 hand 21.8 inches = 1 Bible cubit6 inches = 1 span 2-1/2 feet = 1 military pace
Square Measure144 square inches = 1 square foot 40 square rods = 1 rood9 square feet = 1 square yard 4 roods = 1 acre30-1/4 square yards = 1 square rod 640 acres = 1 square mile
Surveyors’ Measure7.92 inches = 1 link 36 square miles (6 miles square) = 1 township25 links = 1 rod 4 rods = 1 chain10 square chains or 160 square rods = 1 acre 640 acres = 1 square mile
Cubic Measure1728 cubic inches = 1 cubic foot 1 cubic foot = about four-fifths of a bushel27 cubit feet = 1 cubic yard 128 cubic feet = 1 cord (wood)2150.42 cubic inches = 1 standard bushel 40 cubic feet = ton (shipping268.8 cubic inches = 1 standard gallon
Long Measure12 inches = 1 foot 40 rods = 1 furlong3 feet = 1 yard 8 furlongs = 1 statute mile5-1/2 yards = 1 rod 3miles = 1 league
ME
TR
IC A
ND
DE
CIM
AL
EQ
UIV
AL
EN
TS
OF
FR
AC
TIO
NS
OF
AN
IN
CH
(Bu
reau
of
Sta
nd
ard
s)
On
all
elec
tric
al i
nst
alla
tio
ns
that
req
uir
e fu
ses,
sp
ecif
y S
HA
WM
UT
fu
ses.
Yo
u w
ill t
hen
be
in n
o d
ou
bt
that
th
e fu
llest
req
uir
emen
ts i
n f
usi
ng
hav
e b
een
met
.
FERRAZ SHAWMUT
84
1/32
3/64
1/16
5/64
3/32
7/64 1/
8
9/64
5/32
11/6
4
3/16
13/6
4
7/32
15/6
4
1/4
.031
3
.046
9
.062
5
.078
1
.093
8
.109
4
.125
0
.140
6
.156
3
.171
9
.187
5
.203
1
.218
8
.234
4
.250
0
0.79
4
1.19
1
1.58
8
1.98
5
2.38
1
2.77
8
3.17
5
3.57
2
3.96
9
4.36
6
4.76
3
5.15
9
5.55
6
5.95
3
6.35
0
9/32
19/6
4
5/16
21/6
4
11/3
2
23/6
4
3/8
25/6
4
13/3
2
27/6
4
7/16
29/6
4
15/3
2
31/6
4
1/2
.281
3
.296
9
.312
5
.328
1
.343
8
.359
4
.375
0
.390
6
.406
3
.421
9
.437
5
.453
1
.468
8
.484
4
.500
0
7.14
4
7.54
1
7.93
8
8.33
4
8.73
1
9.12
8
9.52
5
9.92
2
10.3
19
10.7
16
11.1
13
11.5
09
11.9
06
12.3
03
12.7
00
17/3
2
35/6
4
9/16
37/6
4
19/3
2
39/6
4
5/8
41/6
4
21/3
2
43/6
4
11/1
6
45/6
4
23/3
2
47/6
4
3/4
.531
3
.546
9
.562
5
.578
1
.593
8
.609
4
.625
0
.640
6
.656
3
.671
9
.687
5
.703
1
.718
8
.734
4
.750
0
13.4
94
13.8
91
14.2
88
14.6
84
15.0
81
15.4
78
15.7
85
16.2
72
16.6
69
17.0
66
17.4
63
17.8
59
18.2
56
18.6
53
19.0
50
25/3
2
51/6
4
13/1
6
53/6
4
27/3
2
55/6
4
7/8
57/6
4
29/3
2
59/6
4
15/1
6
61/6
4
31/3
2
63/6
4 1
.781
3
.796
9
.812
5
.828
1
.843
8
.859
4
.875
0
.890
6
.906
3
.921
9
.937
5
.953
1
.968
8
.984
4
1.00
00
19.8
44
20.2
41
20.6
38
21.0
34
21.4
31
21.8
28
22.2
25
22.6
22
23.0
19
23.4
16
23.8
13
24.2
09
24.6
06
25.0
03
25.4
00
Fra
ctio
ns
of
an i
nch
Dec
imal
Eq
uiv
.M
illi-
met
ers
Fra
ctio
ns
of
an i
nch
Dec
imal
Eq
uiv
.M
illi-
met
ers
Fra
ctio
ns
of
an i
nch
Dec
imal
Eq
uiv
.M
illi-
met
ers
Fra
ctio
ns
of
an i
nch
Dec
imal
Eq
uiv
.M
illi-
met
ers
FERRAZ SHAWMUT
85
DECIMAL EQUIVALENTS, SQUARES, CUBES,SQUARE AND CUBE ROOTS, CIRCUMFERENCES AND
AREAS OF CIRCLES, FROM 1/64 TO 1/2 INCH
Decimal Square Cube Circle*Fraction Equiv. Square Root Cube Root Circum. Area
1/64
1/32
3/64
1/16
5/64
3/32
7/64
1/8
9/64
5/32
11/64
3/16
13/64
7/32
15/64
1/4
17/64
9/32
19/64
5/16
21/64
11/32
23/64
3/8
25/64
13/32
27/64
7/16
29/64
15/32
31/64
1/2
.015625
.03125
.046875
.0625
.078125
.09375
.109375
.125
.140625
.15625
.171875
.1875
.203125
.21875
.234375
.25
.265625
.28125
.296875
.3125
.328125
.34375
.359375
.375
.390625
.40625
.421875
.4375
.453125
.46875
.484375
.5
.0002441
.0009766
.0021973
.0039063
.0061035
.0087891
.0119629
.015625
.0197754
.0244141
.0295410
.0351563
.0412598
.0478516
.0549316
.0625
.0705566
.0791016
.0881348
.0976562
.107666
.118164
.129150
.140625
.1525879
.1650391
.1779785
.1914063
.2053223
.2197266
.2346191
.25
.125
.176777
.216506
.25
.279508
.306186
.330719
.353553
.375
.395285
.414578
.433013
.450694
.467707
.484123
.5
.515388
.530330
.544862
.559017
.572822
.586302
.599479
.612372
.625
.637377
.649519
.661438
.673146
.684653
.695971
.707107
.000003815
.000030518
.000102997
.00024414
.00047684
.00082397
.0013084
.0019531
.0027809
.0038147
.0050774
.0065918
.0083809
.010468
.012875
.015625
.018742
.022247
.026165
.030518
.035328
.040619
.046413
.052734
.059605
.067047
.075085
.083740
.093037
.102997
.113644
.125
.25
.31498
.36056
.39685
.42749
.45428
.47823
.5
.52002
.53861
.55600
.57236
.58783
.60254
.61655
.62996
.64282
.65519
.66710
.67860
.68973
.70051
.71097
.72112
.73100
.74062
.75
.75915
.76808
.77681
.78535
.79370
.04909
.09817
.14726
.19635
.24544
.29452
.34361
.39270
.44179
.49087
.53996
.58905
.63814
.68722
.73631
.78540
.83449
.88357
.93266
.98175
1.03084
1.07992
1.12901
1.17810
1.22718
1.27627
1.32536
1.37445
1.42353
1.47262
1.52171
1.57080
.000192
.000767
.001726
.003068
.004794
.006903
.009396
.012272
.015532
.019175
.023201
.027611
.032405
.037583
.043143
.049087
.055415
.062126
.069221
.076699
.084561
.092806
.101434
.110445
.119842
.129621
.139784
.150330
.161260
.172573
.184269
.196350
*Fraction represents diameter
FERRAZ SHAWMUT
86
DECIMAL EQUIVALENTS, SQUARES, CUBES,SQUARE AND CUBE ROOTS, CIRCUMFERENCES AND
AREAS OF CIRCLES, FROM 33/64 TO 1/2 INCH
Decimal Square Cube Circle*Fraction Equiv. Square Root Cube Root Circum. Area
33/64
17/32
35/64
9/16
37/64
19/32
39/64
5/8
41/64
21/32
43/64
11/16
45/64
23/32
47/64
3/4
49/64
25/32
51/64
13/16
53/64
27/32
55/64
7/8
57/64
29/32
59/64
15/16
61/64
31/32
63/64
1
.515625
.53125
.546875
.5625
.578125
.59375
.609375
.625
.640625
.65625
.671875
.6875
.703125
.71875
.734375
.75
.765625
.78125
.796875
.8125
.828125
.84375
.859375
.875
.890625
.90625
.921875
.9375
.953125
.96875
.984375
1
.265869
.282227
.299072
.316406
.334229
.352539
.371338
.390625
.410400
.430664
.451416
.472656
.494385
.516602
.539307
.5625
.586182
.610352
.635010
.660156
.685791
.711914
.738525
.765625
.793213
.821289
.849854
.878906
.908447
.938477
.968994
1
.718070
.728869
.739510
.75
.760345
.770552
.780625
.790569
.800391
.810093
.819680
.829156
.838525
.847791
.856957
.866025
.875
.883883
.892679
.901388
.910014
.918559
.927024
.935414
.943729
.951972
.960143
.968246
.976281
.984251
.992157
1
.137089
.149933
.163555
.177979
.193226
.209320
.226284
.244141
.262913
.282623
.303295
.324951
.347614
.371307
.396053
.421875
.448795
.476837
.506023
.536377
.567921
.600677
.634670
.669922
.706455
.744293
.783459
.823975
.865864
.909149
.953854
1
.80188
.80990
.81777
.82548
.83306
.84049
.84780
.85499
.86205
.86901
.87585
.88259
.88922
.89576
.90221
.90856
.91483
.92101
.92711
.93313
.93907
.94494
.95074
.95647
.96213
.96772
.97325
.97872
.98412
.98947
.99476
1
1.61988
1.66897
1.71806
1.76715
1.81623
1.86532
1.91441
1.96350
2.01258
2.06167
2.11076
2.15984
2.20893
2.25802
2.30711
2.35619
2.40528
2.45437
2.50346
2.55254
2.60163
2.65072
2.69981
2.74889
2.79798
2.84707
2.89616
2.94524
2.99433
3.04342
3.09251
3.14159
.208813
.221660
.234891
.248505
.262502
.276884
.291648
.306796
.322328
.338243
.354541
.371223
.388289
.405737
.423570
.441786
.460386
.479369
.498736
.518486
.538619
.559136
.580036
.601320
.622988
.645039
.667473
.690291
.713493
.737078
.761046
.785398
*Fraction represents diameter
AREAS AND CIRCUMFERENCES OF CIRCLES
Diam. Circum. Area Diam. Circum. Area1/641/323/641/163/32
1/8
5/323/167/32
1/4
9/325/16
11/323/8
13/327/16
15/321/2
17/329/16
19/325/8
21/3211/1623/32
3/4
25/3213/1627/32
7/8
29/3215/1631/32
1.
1/161/8
3/161/4
5/163/8
7/161/2
9/165/8
11/163/4
13/167/8
15/16
.049087
.098175
.147262
.196350
.294524
.392699
.490874
.589049
.687223
.785398
.883573
.9817481.079921.17810
1.276271.374451.472621.57080
1.668971.767151.865321.96350
2.061672.159842.258022.35619
2.454372.552542.650722.74889
2.847072.945243.043423.14159
3.337943.534293.730643.92699
4.123344.319694.516044.71239
4.908745.105095.301445.49779
5.694145.890496.08684
.00019
.00077
.00173
.00307
.00690
.01227
.01917
.02761
.03758
.04909
.06213
.07670
.09281.11045
.12962
.15033
.17257
.19635
.22166
.24850
.27688
.30680
.33824
.37122
.40574
.44179
.47937
.51849
.55914
.60132
.64504
.69029
.73708
.78540
.88664
.994021.10751.2272
1.35301.48491.62301.7671
1.91752.07392.23652.4053
2.58022.76122.9483
2.1/16
1/83/16
1/4
5/163/8
7/161/2
9/165/8
11/163/4
13/167/8
15/163.
1/161/8
3/161/4
5/163/8
7/161/2
9/165/8
11/163/4
13/167/8
15/164.
1/161/8
3/161/4
5/163/8
7/161/2
9/165/8
11/163/4
13/167/8
15/165.
6.283196.479536.675886.872237.06858
7.264937.461287.657637.85398
8.050338.246688.443038.63938
8.835739.032089.228439.42478
9.621139.81748
10.013810.2102
10.406510.602910.799210.9956
11.191911.388311.584611.7810
11.977312.173712.370012.5664
12.762712.959113.155413.3518
13.548113.744513.940814.1372
14.333514.529914.726214.9226
15.118915.315315.511615.7080
3.14163.34103.54663.75833.9761
4.20004.43014.66644.9087
5.15725.41195.67275.9396
6.21266.49186.77717.0686
7.36627.66997.97988.2958
8.61798.94629.28069.6211
9.967810.32110.68011.045
11.41611.79312.17712.566
12.96213.36413.77214.186
14.60715.03315.46615.904
16.34916.80017.25717.721
18.19018.66519.14719.635
FERRAZ SHAWMUT
87
FERRAZ SHAWMUT
88
For angles over 45°, use titles at bottom of page.
TRIGONOMETRIC FUNCTIONS
Angle- Deg. Sine Cos Tan Cot Angle-Deg.
Angle-Deg. Cos Sine Cot Tan Angle-Deg.
012345
6789
10
1112131415
1617181920
2122232425
2627282930
3132333435
3637383940
4142434445
.0000
.0175
.0349
.0523
.0698
.0872
.1045
.1219
.1392
.1564
.1736
.1908
.2079
.2250
.2419
.2588
.2756
.2924
.3090
.3256
.3420
.3584
.3746
.3907
.4067
.4226
.4384
.4540
.4695
.4848
.5000
.5150
.5299
.5446
.5592
.5736
.5878
.6018
.6157
.6293
.6428
.6561
.6691
.6820
.6947
.7071
1.0000.9998.9994.9986.9976.9962
.9945
.9925
.9903
.9877
.9848
.9816
.9781
.9744
.9703
.9659
.9613
.9563
.9511
.9455
.9397
.9336
.9272
.9205
.9135
.9063
.8988
.8910
.8829
.8746
.8660
.8572
.8480
.8337
.8290
.8192
.8090
.7986
.7880
.7771
.7660
.7547
.7431
.7314
.7193
.7071
.0000
.0175
.0349
.0524
.0699
.0875
.1051
.1228
.1405
.1584
.1763
.1944
.2126
.2309
.2493
.2679
.2867
.3057
.3249
.3433
.3640
.3839
.4040
.4245
.4452
.4663
.4877
.5095
.5317
.5543
.5774
.6009
.6249
.6494
.6745
.7002
.7265
.7536
.7813
.8098
.8391
.8693
.9004
.9325
.96571.0000
Infinite57.2928.6419.0814.3011.43
9.5148.1447.1156.3145.671
5.1454.7054.3324.0113.732
3.4873.2713.0782.9042.748
2.6052.4752.3562.2462.146
2.0501.9631.8811.8041.732
1.6641.6001.5401.4831.428
1.3761.3271.2801.2351.192
1.1501.1111.0721.0361.000
908988878685
8483828180
7978777675
7473727170
6968676665
6463626160
5958575655
5453525150
4948474645
FERRAZ SHAWMUT
89
FERRAZ SHAWMUT
90
FERRAZ SHAWMUT
91
WEIGHTS OF VARIOUS SUBSTANCES AND METALS
Weightper Cubic
Substances Foot,Lbs.
Asbestos ..............................125-175Asphaltum......................................87Brick......................................125-137Brick, Fire ....................................144Brickwork, in mortar ....................100Brickwork, in cement....................112Cement, Set ................................178Chalk............................................163Charcoal, Oak................................35Charcoal, Pine ....................17.5-27.5Concrete ......................................137Earth, loose....................................75Earth, rammed ............................120Emery ..........................................250Glass, common............................163Granite ........................................166Gravel ..........................................110Gypsum........................................140Gypsum, Burnt ............................113Ice ..................................................56Ivory ............................................117Kaolin ..........................................137Lead acetate ................................150Lime, Slaked ............................81-87Limestone ....................................166Litharge, Artificial ........................583Magnetite ....................................315Marble ..................................157-177Masonry ................................116-144Mortar ..........................................109Plaster of Paris ............................112Pyrites ..................................306-324Pyrolusite ..............................231-287Sand, dry ....................................100Sandstone....................................145Slate ............................................165Soapstone....................................170Tile................................................115Trap..............................................185
Weightper Cubic
Metals and Alloys Foot, Lbs.
Aluminum, cast ............................160Antimony, solid ............................418Barium..........................................242Bismuth, solid ..............................617Boron ..........................................162Brass, yellow, 70 Cu. + 30
Zn. cast ..................................527Brass, red 90 Cu + 10 Zn ............536Brass, white, 50 Cu. + 50 Zn. ......511Bronze, 90 Cu. + 10 Sn. ..............548Bronze, 85 Cu. + 15 Sn. ..............555Bronze, 75 Cu. + 25 Sn. ..............551Cadmium......................................536Calcium..........................................98Chromium ....................................410Cobalt, wrought............................563Copper, cast ................................555Gold ..........................................1207German Silver..............................523Iridium ........................................1380Iron, grey, cast ............................442Iron,white, cast ............................478Iron, wrought................................490Lead ............................................709Magnesium ..................................107Manganese ..........................428-500Mercury ........................................848Molybdenum ................................530Nickel ....................................517-555Platinum ....................................1338Potassium, solid ............................54Silver ............................................655Sodium ........................................612Steel ............................................486Strontium......................................160Tin ................................................455Titanium ......................................341Tungsten ....................................1193Vanadium ....................................342Zinc, cast ....................................447
CO
MP
AR
AT
IVE
PH
YS
ICA
LA
ND
ME
CH
AN
ICA
LP
RO
PE
RT
IES
OF
ME
TAL
SP
hys
ical
Pro
per
ties
(A
pp
roxi
mat
e)(W
hit
ehea
d M
etal
Pro
du
cts
Co
mp
any,
In
c.)
SH
AW
MU
Tde
sign
s fo
r pr
otec
tion,
whi
ch is
you
r su
rest
eco
nom
y.
FERRAZ SHAWMUT
92
Mon
elN
icke
lIn
cone
lC
oppe
rB
rass
Pho
spho
r B
ronz
eE
verd
urN
icke
l Silv
erIr
onS
teel
Cas
t Ir
onD
uriro
n14
% C
r Ir
on!7
% C
r Ir
on18
/8 C
r/N
i Iro
nZ
inc
Lead
Alu
min
umD
ural
umin
S
ilver
Pla
tinum
8.80
8.85
8.55
8.89
8.46
8.66
8.30
8.75
7.7
7.9
7.2
7.0
7.7
7.6
7.9
7.14
11.3
82.
72.
810
.51
21.5
1300
-135
014
4013
7010
8390
0 *10
50 *15
3514
0010
00-1
200
1260
1490
1400
1400
420
327
660
600
960
1755
2370
-246
026
2525
0019
8016
50--
--19
20--
--27
9525
5018
30-2
190
2300
2715
2550
2550
760
620
1220
1110
1760
3190
0.12
70.
130
----
0.09
30.
088
0.10
4--
--0.
095
0.11
0--
----
----
----
----
--0.
118
0.09
40.
031
0.21
8--
--0.
056
0.03
2
.000
014
.000
013
.000
013
.000
017
.000
020
.000
018
.000
017
.000
018
.000
013
.000
013
.000
010
.000
028
.000
011
.000
010
.000
017
.000
029
.000
029
.000
024
.000
022
.000
019
.000
008
6.6
15.5
3.5
100
28 ---- 30 7.6
15 6-12
10-1
217
.4 5 5 3.6
29 9 52 40 110
18
4 16 ----
100
28 36 6 5.2
15 3-15
2-12
2.5
2.8
----
2.8
28.2
7.8
56-5
932 10
615
.001
9.0
041
----
.004
0.0
015
.003
9--
--.0
003
.006
2--
----
----
----
--.0
015
----
.004
0.0
041
.004
2--
--.0
040
.003
6
26,0
00,0
0030
,000
,000
31,0
00,0
0016
,000
,000
13,8
00,0
0016
,000
,000
15,0
00,0
0017
,000
,000
25,0
00,0
0030
,000
,000
12-2
7,00
0,00
0--
----
-30
,000
,000
----
---
28,6
00,0
0013
,700
,000
800,
000
10,0
00,0
0010
,000
,000
9,00
0,00
023
,000
,000
Den
sity
Mel
ting
Poi
ntD
egre
es C
Mel
ting
Poi
ntD
egre
es F
Spe
cific
Hea
t
Hea
t E
xpan
sion
Per
°C
Hea
tC
ond’
y%
of
Cu
Ele
cC
ond’
y%
of C
u
Coe
f. of
Ele
c. R
esP
er °
C
Mod
ulas
of E
last
’yps
i
* V
arie
s ac
cord
ing
to G
rade
ME
CH
AN
ICA
LP
RO
PE
RT
IES
(A
PP
RO
XIM
AT
E)
FERRAZ SHAWMUT
93
Mon
el
Nic
kel
Inco
nel
Cop
per
Bra
ss
Pho
spho
r B
ronz
e
Eve
rdur
Nic
kel S
ilver
Wro
ught
Iro
nM
ild S
teel
Allo
y S
teel
(312
0)14
% C
r Ir
on
17%
Cr
Iron
18/8
Cr/
Ni I
ron
Alu
min
um
Dur
alum
in
Lead
Ane
aled
Hot
-Wor
ked
Col
d-W
orke
dA
nnea
led
Ann
eale
dC
old-
Wor
ked
Ann
eale
d C
old-
Wor
ked
Ann
eale
d C
old-
Wor
ked
Ann
eale
dC
old-
Wor
ked
Ann
eale
dC
old-
Wor
ked
Ann
eale
dC
old-
Wor
ked
Ann
eale
dH
eat-
Tre
ated
Hea
t-T
reat
edA
nnea
led
Hot
-Wor
ked
Ann
eale
dH
ot-W
orke
dA
nnea
led
Col
d-W
orke
dA
nnea
led
Col
d-W
orke
dA
nnea
led
Hea
t-T
reat
ed--
----
-
70-8
5,00
080
-105
,000
75-1
75,0
0065
-75,
000
80-9
5,00
0to
200
,000
30,0
00--
----
-45
,000
80-8
5,00
050
,000
to 1
45,0
0065
-70,
000
85-1
10,0
0050
,000
70,0
0040
-50,
000
75,0
0011
6,00
080
,000
100-
115,
000
70-7
5,00
085
-95,
000
80-9
0,00
0to
300
,000
12-1
5,00
020
,000
25-3
5,00
055
-65,
000
2,80
0
25-3
5,00
040
-85,
000
40-1
50,0
0020
-30,
000
30-4
0,00
0--
----
---
----
---
----
---
----
---
----
---
----
---
----
-25
-30,
000
60-7
0,00
0--
----
---
----
-28
-34,
000
----
---
----
---
----
---
75-8
5,00
045
-55,
000
65-7
5,00
035
-40,
000
----
---
4-7,
000
----
---
7-10
,000
----
---
----
---
20-3
0,00
025
-65,
000
30-1
00,0
0017
-23,
000
20-3
0,00
0--
----
-3,
000
----
---
8,50
036
-38,
000
14,0
00--
----
---
----
---
----
-6,
500
30,0
0021
-26,
0045
,000
85,0
0045
,000
----
---
----
---
----
---
20-2
5,00
0--
----
-2-
3,00
012
,000
7-10
,000
30-4
4,00
0<
21,0
00
35,0
0035
-40,
000
35-5
0,00
030
,000
----
---
----
---
10,0
0016
,500
18,0
0025
,000
20,0
00--
----
-25
,000
----
---
20,0
0023
,000
24,0
0035
,000
----
---
----
---
----
---
----
---
----
---
45,0
00--
----
-
6,00
08,
000
14,0
0018
,000
----
---
50-3
545
-20
35-1
53-4
355
-45
----
---
75-7
0 15 70 15 70--
----
-60
-50
30-1
350
-40 25
45-4
0 30 23 35--
----
-35
-30
25-2
060
-35
----
---
45-3
0 1820
-15
25-1
8--
----
-
65-7
550
-65
45-7
565
-75
65-7
5--
----
-50
-55 55 70 60 80
----
---
55-6
522
-49 70 50
40-4
5 65 48 75--
----
-70
-75
45-5
060
-70
----
---
75-8
0 6540
-45
20-2
5--
----
-
80-1
0512
5-15
011
0-24
085
-105
----
---
----
---
30-4
0--
----
-50
-60
----
---
60--
----
---
----
---
----
-75
-85
----
---
85-9
5--
----
---
----
---
----
---
----
---
----
---
----
-13
0-14
0--
----
-30
-35
----
---
----
---
90-1
05--
----
-
118-
135
150-
175
115-
250
115-
130
----
---
----
---
----
---
----
---
----
---
----
---
----
---
----
---
----
---
----
---
----
---
----
---
----
---
140-
170
270
160
----
---
140-
175
----
---
----
---
----
---
----
---
----
---
----
---
----
---
----
---
Ten
sile
Str
eng
th p
siY
ield
Po
int
psi
Ela
stic
L
imit
psi
En
du
ran
ceL
imit
psi
Elo
ng
.in
2”
%R
edu
ct.
In A
rea
%B
rin
ell
Har
dn
ess
500
kg.
3,00
0 kg
.
FERRAZ SHAWMUT
94
Aluminum
Antimony
Bismuth
Brass
Cadmium
Climax
Cobalt
Constantan
Copper-annealed
-hand-drawn
German Silver, 18%Ni
Gold
Iron
Lead
Magnesium
Manganin
Mercury
Molybdenum, drawn
Monel
Nichrome
Nickel
Palladium
Phosphor Bronze
Platinum
Silver
Steel, E.B.B.
Steel, maganese
Tantalum
Tin
Tungsten, drawn
Zinc
2.824
41.7
120
7
7.6
87
9.8
49
1.7241
1.771
33
2.44
10
22
4.6
44
95.783
5.7
42
100
7.8
11
7.8
10
1.59
10.4
70
15.5
11.5
5.6
5.8
0.0039
0.0036
0.004
0.002
0.0038
0.0007
0.0033
0.00001
0.00393
0.00382
0.0004
0.0034
0.005
0.0039
0.004
0.00001
0.00089
0.004
0.002
0.0004
0.006
0.0033
0.0018
0.003
0.0038
0.005
0.001
0.0031
0.0042
0.0045
0.0037
2.7
6.6
9.8
8.6
8.6
8.1
8.71
8.9
8.89
8.89
8.4
19.3
7.8
11.4
1.74
8.4
13.546
9
8.9
8.2
8.9
12.2
8.9
21.4
10.5
7.7
7.5
16.6
7.3
19
7.1
30.000
--
--
70,000
--
150,000
--
120,000
30,000
60,000
150,000
20,000
50,000
3,000
33,000
150,000
0
100,000
160,000
150,000
120,000
39,000
25,000
50,000
42,000
53,000
230,000
--
4,000
500,000
10,000
659
630
271
900
321
1250
1480
1190
1083
1083
1100
1063
1530
327
651
910
-38.9
25.00
1300
1500
1452
1550
750
1755
960
1510
1260
2850
232
3400
419
Metal
ResistivityMicrohm-Cm
20°C
Temp. Coeff.of Resistivity
per °CSpecificGravity
TensileStrengthlbs./in.
2
Melting Point
°C
PROPERTIES OF METALS AS CONDUCTORS
FERRAZ SHAWMUT
95
CONDUIT AND TUBING DIMENSIONS AND AREAS(National Electric Products Corp.)
Diagram shows smallest equivalent diameter of group of wires and diameter ofconduit in terms of diameter of a single wire. Diameter of conduit is for runs offrom 50 ft. with 3-90° bends to 150 ft. with 1-90° bend. For more difficult runsincrease diameter of conduit to 115%; for less difficult, decrease to 87%.A = Diameter in conduit in terms of C.B = Smallest equivalent diameter of group of wires in terms of C.C = Diameter of individual wire. Use conduit size with internal diameter nearestA x C.Example: 4 #10 wires require 3.1 x .63 = 1.95” or a 2” conduit (Assume dia. #10wire = .63”)
1/2”3/4”
1”1 1/4”1 1/2”
2”2 1/2”
3”3 1/2
4”4 1/2”
5”6”
.622”
.824”1.049”1.380”1.610”2.067”2.469”3.068”3.548”4.026”4.506”5.047”6.065”
100%
.304
.533
.8641.4962.0363.3564.7887.3939.887
12.7315.9520.0028.89
60%
.182
.320
.518
.8981.2222.0142.8734.4365.9327.6389.570
12.00017.334
50%
.152
.267
.432
.7481.0181.6782.3943.6974.9446.3657.975
10.00014.445
40%
.122
.213
.346
.598
.8141.3421.9152.9573.9555.0926.3808.000
ConduitSize
InternalDiameter
Internal Area Sq. In.
DIM
EN
SIO
NS
AN
D W
EIG
HT
SR
IGID
CO
ND
UIT
, P
IPE
, AN
D E
LE
CT
RIC
AL
ME
TAL
LIC
TU
BIN
G(G
arla
nd
Man
ufa
ctu
rin
g C
om
pan
y)
FERRAZ SHAWMUT
96
1/8
1/4
3/8
1/2
3/4 1
1 1/
41
1/2 2
2 1/
2 33
1/2 4
4 1/
2 5 6 8 10 12
27 18 18 14 14
11 1
/211
1/2
11 1
/211
1/2 8 8 8 8 8 8 8 8 8 8
----
----
0.49
30.
622
0.82
4
1.04
91.
380
1.61
02.
067
2.46
9
3.06
83.
548
4.02
64.
506
5.04
7
6.06
5--
----
----
--
----
----
0.67
50.
840
1.05
0
1.31
51.
660
1.90
02.
375
2.87
5
3.50
04.
000
4.50
05.
000
5.56
3
6.62
5--
----
----
--
----
----
56.8
85.2
113.
4
168.
422
8.1
273.
136
7.8
581.
9
761.
692
0.2
1089
.12
64.
1481
.
1919
.--
----
----
--
0.26
9.3
64.4
93.6
22.8
24
1.04
91.
380
1.61
02.
067
2.46
9
3.06
83.
548
4.02
64.
506
5.04
7
6.06
57.
981
10.0
2012
.000
0.40
5.5
40.6
75.8
401.
050
1.31
51.
660
1.90
02.
375
2.87
5
3.50
04.
000
4.50
05.
000
5.56
3
6.62
58.
625
10.7
5012
.750
24.5
42.5
56.8
85.2
113.
4
168.
422
8.1
273.
136
7.8
581.
9
761.
692
0.2
1089
.12
64.
1481
.
1919
.28
81.
4113
.50
71.
0.21
5.3
02.4
23.5
46.7
42
.957
1.27
81.
500
1.93
92.
323
2.90
0 3.
364
3.82
64.
290
4.81
3
5.76
17.
625
9.75
011
.750
0.40
5.5
40.6
75.8
401.
050
1.31
51.
660
1.90
02.
375
2.87
5
3.50
04.
000
4.50
05.
000
5.56
3
6.62
58.
625
10.7
5012
.750
31.4
53.5
73.8
108.
714
7.3
217.
129
9.6
363.
150
2.2
766.
1
1025
.12
51.
1498
.17
61.
2079
.
2857
.43
39.
5474
.65
42.
----
----
.493
.622
.824
1.04
91.
380
1.61
02.
067
----
----
----
----
----
----
----
----
----
----
----
----
.577
.706
.922
1.16
31.
508
1.73
82.
195
----
----
----
----
----
----
----
----
----
----
----
----
25.0
32.1
48.8
71.1
100.
011
8.0
150.
0--
--
----
----
----
----
----
----
----
----
----
No
min
alS
ize
in
Inch
es
Th
read
sp
erIn
chI.D
.In
ches
I.D.
Inch
esI.D
.In
ches
I.D.
Inch
esO
.D.
Inch
esO
.D.
Inch
esO
.D.
Inch
esO
.D.
Inch
es
Lb
s.L
bs.
Lb
s.L
bs.
100
Ft.
100
Ft.
100
Ft.
100
Ft.
EL
EC
TR
UN
ITE
ST
EE
LT
UB
ES
, E
LE
CT
RIC
AL
ME
TAL
LIC
TU
BIN
GE
XT
RA
ST
RO
NG
IRO
N P
IPE
STA
ND
AR
D
IRO
N P
IPE
RIG
ID S
TE
EL
CO
ND
UIT
FERRAZ SHAWMUT
97
FERRAZ SHAWMUT
98
HARDNESS CONVERSION TABLE (Approximate)
(Industrial Steels, Inc.)Values vary depending on grades and conditions of material involved. Rockwell “B” Scale
should not be used over B-100. The “C” Scale should not be used under C-20.
BrinellShore
Sclero-scope
TensileLbs.
Sq. In.
TensileLbs.
Sq. In.
ShoreSclero-scope
BrinellRockwellRock-well
HardNo.
HardNo.
HardNo.
HardNo.
BScale
BScale
CScale
In 1000Lbs
In 1000Lbs
782744713683652627600578555532512495477460444430418402387375364351340332321311302293286277269262255248241235228223217212207202196192187183179174170166
--------------------------------------------------------------------
100999897969594939291908988878685
726967656361595856545251494847454443414039383736353433313029282726252423222120----------------------
107100969288858178757270686664615957555352504947464544424140393837363635343333323130302929282827272626
383365350334318307294284271260251242233226217210205197189183178172167162157152148144140136132128125121118115113109106104101999694919089888685
1631591561531491461431401371341311281261241211181161141121091071051031019997969593929088878685838281807978777675747372717069
8483828180787776757472717069676665646261595857565453525150494847464544434241403938373635333130292726
25252424232322--------------------------------------------------------------------------------------
8482807978777674737170696766656362616059585756555453535252515049484847474646454544444343424241414040
FERRAZ SHAWMUT
99
1 2 3 4 5 6 8 10 12 1/4
5/16 3/
87/
16 1/2
9/16 5/
83/
47/
8 11
1/8
1 1/
41
3/8
1 1/
21
3/4 2
2 1/
42
1/2
2 3/
4 33
1/4
3 1/
23
3/4 4
•Am
eric
an M
achi
nist
64 56 48 40 40 32 32 24 24 20 18 16 14 13 12 11 10 9 8 7 7 6 6 54
1/2
4 1/
2 4 4 4 4 4 4 4
0.07
3.0
86.0
99.1
12.1
25.1
38.1
64.1
90.2
16.2
500
.312
5.3
750
.437
5.5
000
.562
5.6
250
.750
0.8
750
1.00
001.
1250
1.25
001.
3750
1.50
001.
7500
2.00
002.
2500
2.50
002.
7500
3.00
003.
2500
3.50
003.
7500
4.00
00
0.01
562
.017
86.0
2083
.025
00.0
2500
.031
25.0
3125
.041
67.0
4167
.050
00.0
5556
.062
50.0
7143
.076
92.0
8333
.090
91.1
0000
.111
11.1
2500
.142
86.1
4286
.166
67.1
6667
.200
00.2
2222
.222
22.2
5000
.250
00.2
5000
.250
00.2
5000
.250
00.2
5000
0.06
0.0
73.0
86.0
99.1
12.1
25.1
38.1
64.1
90.2
16.2
500
.312
5.3
750
.437
5.5
000
.562
5.6
250
.750
0.8
750
1.00
001.
1250
1.25
001.
3750
1.50
00
0.01
250
0.01
389
0.01
562
0.01
786
0.02
083
0.02
273
0.02
500
0.02
778
0.03
125
0.03
571
0.03
571
0.04
167
0.04
167
0.05
000
0.05
000
0.05
556
0.05
556
0.06
250
0.07
143
0.07
143
0.08
333
0.08
333
0.08
333
0.08
333
0.04
80.
059
0.07
00.
081
0.09
10.
102
0.11
30.
136
0.15
90.
180
0.21
40.
271
0.33
30.
338
0.45
00.
507
0.56
90.
688
0.80
40.
929
1.04
21.
167
1.29
21.
417
0.05
70.
068
0.07
80.
087
0.10
00.
107
0.13
30.
148
0.17
40.
200
0.25
70.
312
0.36
60.
423
0.47
90.
534
0.65
00.
764
0.87
50.
982
1.10
71.
208
1.33
31.
550
1.77
82.
028
2.25
02.
500
2.75
03.
000
3.25
03.
500
3.75
0
0 1 2 3 4 5 6 8 10 12 1/4
5/16 3/
87/
16 1/2
9/16 5/
83/
47/
8 11
1/8
1 1/
41
3/8
1 1/
2
80 72 64 56 48 44 40 36 32 28 28 24 24 20 20 18 18 16 14 14 12 12 12 12
CL
AS
SIF
ICA
TIO
N O
F F
ITS
Cla
ss 1
, Lo
ose
Fit-
Incl
udes
scr
ew-t
hrea
d w
ork
of r
ough
com
mer
cial
qua
lity,
whe
re t
he t
hrea
ds m
ust
asse
mbl
e re
adily
, an
d a
cert
ain
amou
nt o
f sh
ake
or p
lay
is n
ot o
bjec
tiona
ble.
Cla
ss 2
, F
ree
Fit-
Incl
udes
the
gre
at b
ulk
of s
crew
-thr
ead
wor
k of
ord
inar
y qu
ality
,of
fin
ishe
d an
d se
mi-f
inis
hed
bolts
and
nut
s, m
achi
ne s
crew
s, e
tc.
Cla
ss 3
, M
ediu
m F
it- I
nclu
des
the
bette
r gr
ade
of in
terc
hang
eabl
e sc
rew
-thr
ead
wor
k.C
lass
4,
Clo
se f
it-In
clud
es s
crew
-thr
ead
wor
k re
quiri
ng a
fin
e sn
ug f
it, m
uch
clos
er t
han
the
med
ium
fit.
In
this
cas
e of
fit,
sel
ectiv
e as
sem
bly
of p
arts
may
be
nece
ssar
y.
No
min
alS
ize
No
min
alS
ize
Th
read
sp
er i
n.
Th
read
sp
er I
n.
Maj
or
Dia
met
erIn
ches
Maj
or
Dia
met
erIn
ches
Pit
ch
Inch
AM
ER
ICA
N N
AT
ION
AL
TH
RE
AD
SE
RIE
S (
Nat
ion
al B
ure
au o
f S
tan
dar
ds,
Han
db
oo
k H
-25)
AM
ER
ICA
N N
AT
ION
AL
CO
AR
SE
-TH
RE
AD
SE
RIE
SA
ME
RIC
AN
NA
TIO
NA
LF
INE
-TH
RE
AD
SE
RIE
S
Pit
ch
Inch
Tap
Dri
llS
ize•
Tap
Dri
llS
ize•
Shawmut TRI-ONIC fuses end needless interruption and give complete, flexible,economic protection to a circuit and its equipment under all conditions.
FERRAZ SHAWMUT
100
80
79
78
77
76
75
74
73
72
71
70
69
68
1/32
67
66
65
64
63
62
61
60
59
58
57
56
3/64
55
54
53
1/16
52
51
50
49
48
5/64
47
46
45
44
43
42
3/32
41
40
39
38
37
36
7/64
35
34
33
32
31
1/8
30
29
28
9/64
27
26
25
24
23
5/32
22
21
20
19
18
11/64
17
16
15
14
13
3/16
12
11
10
9
8
7
13/64
6
5
4
3
7/32
2
1
A
15/64
B
C
D
E1/4
F
G
17/64
H
I
K
9/32
L
M
19/64
N
5/16
O
P
21/64
R
11/32
S
T
23/64
U
3/8
V
W
25/64
X
Y
13/32
Z
27/64
7/16
29/64
15/32
31/64
1/2
33/64
17/32
35/64
9/16
37/64
19/32
39/64
5/8
41/64
21/32
43/64
11/16
45/64
23/32
47/64
3/4
49/64
25/32
51/64
13/16
53/64
27/32
55/64
7/8
57/64
29/32
59/64
15/16
61/64
31/32
63/64
.0135
.0145
.016
.018
.020
.021
.0225
.024
.025
.026
.028
.0292
.031
.0312
.032
.033
.035
.036
.037
.038
.039
.040
.041
.042
.043
.0465
.0468
.052
.055
.0595
.0625
.0635
.067
.070
.073
.076
.0781
.0785
.081
.082
.086
.089
.0935
.0937
.096
.068
.0995
.1015
.1040
.1065
.1093
.110
.1111
.113
.116
.120
.125
.1285
.136
.1405
.1406
.144
.147
.1495
.152
.154
.1562
.157
.159
.161
.166
.1695
.1718
.173
.177
.180
.182
.185
.1875
.189
.191
.1935
.196
.199
.201
.2031
.204
.2055
.209
.213
.2187
.221
.228
.234
.2343
.238
.242
.246
.250
.257
.261
.2656
.266
.272
.281
.2812
.290
.295
.2963
.302
.3125
.316
.323
.3281
.339
.3437
.348
.358
.3593
.367
.375
.377
.386
.3906
.397
.404
.4062
.413
.4218
.4375
.4531
.4687
.4843
.500
.5156
.5312
.5468
.5625
.5781
.5937
.6093
.625
.6406
.6562
.6718
.6875
.7031
.7187
.7343
.750
.7656
.7812
.7968
.8125
.8281
.8437
.8593
.875
.8906
.9062
.9218
.9375
.9531
.9687
9843
DrillSize
DrillSize
DrillSize
DrillSize
DrillSize
Dia.Inches
Dia.Inches
Dia.Inches
Dia.Inches
Dia.Inches
DRILL SIZES
FERRAZ SHAWMUT
101
SHEET METAL GAUGE
United States Standard Gauge for Sheet and Plate Steel (USS Gauge)
UNCOATED SHEETS
8............................................. .1644
9............................................. .1494
10............................................ .1345
11............................................ .1196
12............................................ .1046
13............................................ .0897
14............................................ .0747
15............................................ .0673
16............................................ .0598
17............................................ .0538
18............................................ .0478
19............................................ .0418
20............................................ .0359
21............................................ .0329
22............................................ .0299
23............................................ .0269
24............................................ .0239
25............................................ .0209
26............................................ .0179
27............................................ .0164
28............................................ .0149
29............................................ .0135
30............................................ .012
8............................................. .1681
9............................................. .1532
10............................................ .1382
11............................................ .1233
12............................................ .1083
13............................................ .0934
14............................................ .0785
15............................................ .0710
16............................................ .0635
17............................................ .0575
18............................................ .0516
19............................................ .0456
20............................................ .0396
21............................................ .0366
22............................................ .0336
23............................................ .0306
24............................................ .0276
25............................................ .0247
26............................................ .0217
27............................................ .0202
28............................................ .0187
29............................................ .0172
30............................................ .0157
31............................................ .0142
GaugeNo.
GaugeNo.
GaugeNo.
GaugeNo.
ThicknessInch
ThicknessInch
ThicknessInch
GALVANIZED SHEETS
Note: Due to variation in manufacture a plus or minus tolerance is generallyrecognized, some authorities allowing a 10 percent variation.
ThicknessInch
FERRAZ SHAWMUT
102
PULLEYS
The revolutions of any two pulleys over which a belt is run vary in inverseproportion to their diameters. The pulley that imparts motion to the belt is calledthe “driver,” and that which receives motion is called the “driven.”
From above the following formulas may be deducted:
D = diameter of driverd = diameter of drivenN = number of revolutions in drivern = number of revolutions in driven
D = d = n = N =
Example 1: Diameter of driven pulley 48-inch. Shaft speed 200 R.P.M.Motor speed 1200 R.P.M. Find diameter of motor pulley.
D = by substitution D = = 8-inch diameter of motor pulley.
Example 2: Diameter of motor pulley 8-inch. Motor speed 1200 R.P.M.Shaft speed 200 R.P.M. Find diameter of pulley for shaft.
d = by substitution d = = 48-inch diameter of pulley shaft.
Example 3: Diameter of motor pulley 8-inch. Motor speed 1200 R.P.M.Diameter of pulley on shaft 48-inch. Find speed of shaft.
n = by substitution n = = 200 R.P.M. speedof shaft.
Example 4: Diameter of motor pulley 8-inch. Speed of shaft 200 R.P.M.Diameter of pulley on shaft 48-inch. Find speed of motor.
N = by substitution N = = 1200 R.P.M. speed of motor.
dnN
DNn
DNd
dnD
dnN
48-inch x 2001200
DNn
8-inch x 1200200
DNd
8-inch x 120048
dnD
48-inch x 2008
FERRAZ SHAWMUT
103
SHAFTINGJones & Laughlin Steel Co. gives the following for steel shafts:
Turned Cold-RolledFor simply transmitting power and short countershaft bearings H.P. = d3R � 50 H.P. = d3R � 40not more than 8 ft. apart
As second movers, or line shafts, H.P. = d3R � 90 H.P. = d3R � 70bearings 8ft. apart
As prime movers or head shaftscarrying main driving pulley or gear, H.P. = d3R � 125 H.P. = d3R � 100 well supported by bearings
Horsepower Transmitted by Cold-Rolled Steel Shafting at Different Speedsas Prime Movers or Head Shafts Carrying Main Driving Pulley or Gear,
Well Supported by BearingsReprinted by permission from “Mechanical Engineers” Handbook - Design and Shop Practice”
by Kent, published by John Wiley & Sons, Inc.
Formula H.P. = d3R � 100
For H.P. transmitted by turned steel shafts, as prime movers, etc., multiply the figures by 0.8.
For shafts, as second movers or line shafts, Cold-rolled Turnedbearings 8 ft. apart, multiply by............................................. 1.43 1.11
For simply transmitting power, short countershafts,etc., bearings not over 8ft. apart multiply by......................... 2 2.50
The horsepower is directly proportional to the number of revolutions per minute.SPEED OF SHAFTING - Machine shops 120 to 240
- Wood-working 250 to 300- Cotton and woolen mills 300 to 400
1-1/21-9/161-5/81-11/161-3/41-13/161-7/81-15/1622-1/162-1/82-3/162-1/42-5/162-3/82-7/162-1/22-9/162-5/82-11/162-3/42-13/16
3.43.84.34.85.45.96.67.38.08.89.6
10.511.412.413.414.515.616.818.119.42122
6.77.68.69.6
10.711.913.114.516.017.619.22123252729313436394144
10.111.412.814.416.117.819.7222426293134374043475054586267
13.515.217.119.2212426293235384245495458626772778389
16.919.0212427303336404448525762677278849097
104111
2-7/82-15/1633-1/83-3/163-1/43-3/83-7/163-1/23-9/163-5/83-11/163-3/43-7/83-15/1644-3/164-1/44-7/164-1/24-3/45
2425273132343841434548505558616474778891
107125
4851546165697781869095
100105116122128147154175182214250
7276819197
103115122128136143150158174183192221230263273322375
95101108122129137154162171180190200211233244256294307350365429500
119127135152162172192203214226238251264291305320367383438456537625
Diam. Diam.100 200 300 400 500 100 200 300 400 500
Revolutions per minute Revolutions per minute
�
��
�
�
FERRAZ SHAWMUT
104
BELTING(Suplee)
The power which can be transmitted by a belt is measured by the pull and by thelineal velocity at which the belt travels. The pull is limited by the strength of the beltand by the friction upon the pulleys, while the lineal velocity is dependent upon therevolving speed of the pulleys and upon their diameter. If it is attempted to increasethe strength by increasing the thickness, it is possible that the stiffness of the beltwill prevent it from wrapping closely about the pulley, and hence the friction will bereduced. If the speed is made too high, the centrifugal force will act to throw thebelt out of close contact with the pulley and the friction will again be reduced. Thereare, therefore, several practical limits within which satisfactory belt transmissionsshould be kept.
The tension which can be maintained in actual practice ranges from about 30 to60 pounds per inch of width for single ply belts 3/16” thick, 65 to 95 pounds for dou-ble ply belts 3/8” thick, and 130 to 160 pounds for four ply belts 3/4” thick.
If a high tension is put on a belt, it will gradually diminish, owing to stretch, untilstress upon it becomes low enough to check further stretching. If this tension issufficient to transmit the power, the transmission will run well, while if the load istoo heavy the belt will slip and it must be either tightened or a change made in thewidth or speed.
If the power to be transmitted is given in horsepower, we have 33,000 foot-poundsper minute to consider. If the belt tension is to be 30 pounds per inch of width, wemust, therefore, have a speed of 1100 feet per minute. If the speed is one-half asmuch, the width must be twice as great, and so the given elements must be takenand the others found. Usually, the speed and the power are given and the widthrequired.
If
w = width, in inchess = speed, in feet, per minuteN = horsepowert = tension, per inch width of belt
we have
N = w = s = tws
3300033000 N
ts33000 N
tw
FERRAZ SHAWMUT
105
Or, if we have given the width, speed and horsepower, the minimum tension whichcan be reached before slipping will occur is
t =
Thus, if a belt 10 inches wide, running at 4000 feet per minute, is transmitting 50horsepower the tension is
t = = 41.25 pounds
The tension available for transmitting power is really the difference between the ten-sions of the tight and slack sides, since there must always be tension enough on theslack side to secure sufficient friction on the pulley to keep the belt from slipping.
If we take the formula N =
and write it N = x
the last term will represent square feet per minute passing a given point. By substi-tuting any value for t, and making N=1, we can thus find how many square feet perminute will transmit a horsepower. Good, practical belting rules are: For single belts,60 square feet per minute equals 1 horsepower; and for double belts, 40 square feetper minute equals 1 horsepower. These correspond to 45 pounds and 68 poundstension per inch of width, respectively - tensions which are readily maintained inpractice.
These values are based on the assumption that the belt embraces 180° of each pul-ley. If the arc of contact is less, the power transmitted may be taken in the followingproportions:
Percentage of Efficiency for Various Arcs of Contact
90° 100° 110° 120° 130° 140° 150° 160° 170° 180°0.65 0.70 0.75 0.79 0.83 0.87 0.91 0.94 0.97 1.00
The power of 180° is to be multiplied by the percentage coefficient for other arcs.Thus, for 130° only 83 percent as much power is transmitted as with 180°.
33000 Nws
33000 x 5010 x 4000
t x 1233000
ws12
tws33000
FERRAZ SHAWMUT
106
QUICK 3 PHASE SHORT-CIRCUIT CALCULATIONS
Short circuit levels must be known before fuses can be correctly applied. For fuses, unlikecircuit breakers, there are only four levels of interest. These are 10,000, 50,000, 100,000 and200,000 RMS symmetrical amperes.
Rigorous determination of short circuit currents requires accurate reactance and resistancedata for each power carrying component from the utility generating station right to the point offault. It is impractical for a plant engineer to collect all this information and yet he is the onemost affected by short circuit hazards.
There have been several approaches to “easy” short circuit calculations which have beenbeen too cumbersome to be of practical use. The method described here is not new but it isupdated and more comprehensive than before and is the simplest of all approaches.
In summary, each basic component of the industrial electrical distribution system is pre-assigned a single factor based on the impedance it adds to the system. For instance, a 1000KVA, 480 volt, 5.75%Z transformer has a factor of 4.80. This factor corresponds with 25,000RMS short circuit amperes. (directly read on Scale 1)Note: Factors change directly with transformer impedance. If this transformer were 5.00%Z,the factor would be 5.00/5.75 x 4.80 = 4.17.
Cable and bus factors are based on 100 foot lengths. Shorter or longer lengths have pro-portionally smaller or larger factors (i.e. 50’ length = 1/2 factor; 200’ length = 2 x factor).
To find the short circuit current at any point in the system, simply add the factors as theyappear in the system from the entrance to the fault point and read the available current onScale 1.Example #1:
What is the potential short circuit at various points in a 480V, 3-phase system fed by a1000 KVA, 5.75%Z transformer? (Assume primary short circuit power to be 500 MVA).
Answer:
Example #2:If the primary short circuit power were 50MVA (instead of 500MVA) in this same system.
what would the Isc be at the transformer? At the end of the bus duct run?Answer:
From the Primary MVA correction factor table (next page), the factor is 50MVA (at 480V) is1.74. The new Factor at the transformer is 4.80 + 1.74 = 6.54 and Isc is reduced to 18,000A.The new factor at the bus duct is 9.20 + 1.74 = 10.94 and Isc is 11,000A.
FERRAZ SHAWMUT
107
QUICK 3 PHASE SHORT-CIRCUIT CALCULATIONS cont.
FactorsA.Transformers - 3�(Transformer factorsare based on available primaryshort circuit powerof 500 MVA.)
A.1 TransformerCorrection FactorsFor systems with other than500 MVA primary short circuitpower, add the appropriatecorrection factors in this tableto the transformer factor.
A2. Second 3� Transformer in System1. Determine system factor at the second transformer primary.
Example: Isc @ 480V = 40,000A. Factor is 3.002. Adjust factor in proportion to voltage ratio of 480/208V transformer.
Example: For 208V, Factor changes to (208 � 480) x 3.00 = 1.303. Add factor for second 3� transformer.
Example: Factor for 100 KVA, 208V, 1.70%Z transformer is 7.00Total Factor = 7.00 = 1.30 = 8.30 (Isc = 14,500A)
NOTES: 208 VOLT 3� transformer factors are calculated for 50% motor load.240, 480 and 600 volt 3� transformer factors are calculated for100% motor load.A phase-to-phase fault is .866 times the calculated 3-phase value.
75 KVA 1.60%Z100 KVA 1.70%Z
112.5 KVA 2.00%Z150 KVA 2.00%Z225 KVA 2.00%Z300 KVA 2.00%Z500 KVA 2.50%Z750 KVA 5.75%Z
1000 KVA 5.75%Z1500 KVA 5.75%Z2000 KVA 5.75%Z2500 KVA %.75%Z
9.007.007.405.403.702.702.152.782.241.48N.A.N.A.
10.008.008.506.004.003.002.253.252.401.601.20.95
20.0016.0017.0012.00
8.006.004.506.504.803.202.401.91
24.0020.0021.0015.0010.00
7.505.608.006.004.003.002.40
Transformer Size 208 240 480 600
3�
152550
100150250
Infinite
2.821.65
.78
.34
.20
.08-.08
3.241.90
.90
.40
.23
.10-.10
6.433.781.74
.80
.46
.20-.20
8.054.732.241.00
.58
.25-.25
208 240 480 600
PrimaryMVA
3�
NOTE: Factor varies with %ZExample: 50KVA, 240V secondary with a 1.5%Z has a factor
of (1.5%Z � 3.0%Z) x 17.3 = 8.65
FERRAZ SHAWMUT
108
15 KVA 2.5%Z25 KVA 2.5%Z
37.5 KVA 2.8%Z50 KVA 3.0%Z75 KVA 3.0%Z
100 KVA 3.0%Z150 KVA 2.5%Z167 KVA 2.5%Z225 KVA 2.5%Z300 KVA 3.0%Z500 KVA 4.5%Z
34.620.716.612.5
8.286.223.463.102.302.071.86
48.028.823.017.311.58.644.804.313.202.882.59
24.014.411.58.655.754.322.402.161.601.441.30
Transformer Size Diagram A120V
Diagram A240V
Diagram B120V
Single Phase Voltage
QUICK 3 PHASE SHORT-CIRCUIT CALCULATIONS cont.
A3. Single Phase Transformer in 3� SystemTransformer connections must be known before factor can be determined. SeeDiagrams A and B.
1. Determine system factor at 1� transformer primary, with 480V pri.,120/240V sec. (Diagram A)Example: Isc @ 480V = 40,000A, 3�Factor is 3.00
2. Adjustment Factor in proportion to voltage ratio of 480/240V transformer.Example: For 240V, 1�, factor is (240 � 480) 3.45 = 1.70
3. Add Factor 1� transformer with Diagram A connection.Example: Factor for 100 KVA, 120/240V, 3%Z transformer is:a. 120v - Total Factor = 6.22 + 1.70 = 7.92 (Isc = 15,000A)b. 240v - Total Factor = 8.64 + 1.70 = 10.34 (Isc = 11,600A)
Transformers - 1 Phase
1� Factor = = = 3.453 x Factor.886
3.00.886
.6 200,00.7.8 150,000.9
1 120,000110,000100,000
90,000
1.5 80,000
75,000
70,000
65,000
2 60,000
55,000
50,0002.5
45,000
3 40,000
35,000
4 30,000
25,0005
6 20,00078 15,0009
1011
12 10,0009,000148,000167,00018
20 6,00022
24 5,00040 3,00060 2,00080 1,500
100 120 1,000
Scale 1
FERRAZ SHAWMUT
109
QUICK 3 PHASE SHORT-CIRCUIT CALCULATIONS cont.
86421
1/02/03/04/0
250MCM300MCM350MCM400MCM500MCM600MCM750MCM
86421
1/02/03/04/0
250MCM300MCM350MCM400MCM500MCM600MCM750MCM
86421
1/02/03/04/0
250MCM300MCM350MCM400MCM500MCM600MCM750MCM
CableSize
CableSize
CableSize
79.0050.0032.0021.0017.5014.0011.809.808.407.707.006.606.205.805.505.20
68.0043.0028.0018.0015.0012.2010.20
8.507.306.706.105.705.405.004.804.50
34.0022.0014.00
9.007.406.105.104.273.673.373.042.852.702.492.402.26
27.0017.5011.157.235.914.854.053.432.942.702.442.282.162.001.911.80
208 240 480 600
240208 480 600
208 240 480 600
3 � Voltage
3 � Voltage
3 � Voltage
78.0047.9030.7019.9016.2013.2010.60
8.877.576.865.755.365.094.664.294.05
67.6041.5026.7017.2014.0011.409.217.596.555.954.984.644.414.043.723.51
33.8020.7013.30
8.617.075.704.603.853.282.972.492.322.202.021.861.76
27.1016.6010.70
6.895.604.573.683.082.622.381.981.861.751.621.491.41
129.0083.0053.0035.0028.0021.5018.5015.0012.5011.109.908.608.307.407.206.50
112.0072.0046.0030.0024.0018.5016.0013.0011.009.608.607.407.206.406.205.60
56.0036.0023.0015.0012.00
9.708.006.505.504.804.303.703.603.203.102.80
45.0029.0018.5012.00
9.607.706.405.204.403.853.423.002.902.602.442.22
B. Copper Cables in Magnetic Duct (per 100’)
B1. Copper Cables in Non-Magnetic Duct (per 100’)
C. Aluminum Cables in Magnetic Duct (per 100’)
Isc =
For parallel runs divide factorby number of conductors perphase.Example: If factor for a single 500MCM conductor is2.49 then the factor for a runhaving 3-500MCM per phaseis 2.49 � 3 = .83. (Example from Table B 480 volts.)
120,000Total Factor
TotalFactor
1sc
(RMS Amperes)
FERRAZ SHAWMUT
110
86421
1/02/03/04/0
250MCM300MCM350MCM400MCM500MCM600MCM750MCM
129.7580.0051.1033.0026.3021.2017.0013.8011.5010.10
8.137.496.876.125.304.85
112.4569.1044.2025.7022.8018.4014.7012.00
9.958.727.046.505.955.314.594.20
56.2034.6022.1014.3011.409.207.346.024.984.363.523.072.982.662.292.10
45.0027.7017.7011.409.127.365.874.793.993.492.812.452.382.131.831.69
Cable Size 208 240 480 600
600800
100012001350160020002500300040005000
2.851.611.611.211.171.03
.90
.63
.51
.37
.30
2.481.401.401.061.01
.89
.78
.54
.44
.32
.26
1.24.70.70.53.51.45.39.27.22.16.13
.99
.56
.56
.42
.40
.36
.31
.22
.18
.13
.10
2.542.541.901.601.321.19
.90
.70
.60
.43--
2.192.191.651.361.141.03
.77
.60
.52
.38--
1.101.10
.82
.68
.57
.52
.39
.30
.26
.19--
.88
.88
.66
.54
.46
.41
.31
.24
.21
.15--
208 240 480 600 208 240 480 600AmpereRating
Copper Aluminum
400600800
100012001350160020002500300040005000
2.532.531.871.871.471.26
.91
.79
.61
.48
.43
.38
2.182.181.611.611.261.08
.78
.68
.52
.42
.37
.33
1.091.09
.81
.81
.63
.54
.39
.34
.26
.21
.18
.16
.89
.89
.66
.66
.51
.44
.32
.28
.21
.17
.15
.13
3.882.412.411.691.431.301.09
.89
.66
.59
.46
.35
3.342.072.071.451.221.12
.94
.77
.57
.51
.40
.30
1.671.041.04
.73
.61
.56
.47
.38
.28
.25
.20
.15
1.36.84.84.59.50.45.38.31.23.21.16.12
208 240 480 600 208 240 480 600AmpereRating
Copper Aluminum
QUICK 3 PHASE SHORT-CIRCUIT CALCULATIONS cont.
C1. Aluminum Cables In Non-Magnetic Duct (Per 100’)
For parallel runs, divide factors by conductors per phase.Example: 3-500MCM per phase, 240v. New Factor = (5.31 � 3) = 1.77
D. Feeder Bus Duct Factors (per 100’)
Appropriate for use with Feeder Bus Duct Manufactured by ITE, GE, Square D and Westinghouse.
D1. Plug In Bus Duct Factors (per 100’)
Appropriate for use with plug-in Bus Duct Manufactured by GE, Square D and Westinghouse.
3 � Voltage
3 � Voltage
3 � Voltage
FERRAZ SHAWMUT
111
57.
5 10 15 20 2537
.5 50 75 100
125
150
200
250
300
400
500
750
1000
1500
2000
2500
3000
251
376
502
751
1005
1253
1882
2512
3764
5023
6293
7506
1004
612
529
1506
921
824
2511
537
644
4018
575
058
1004
6212
5289
1506
93
125
188
251
376
502
629
941
1253
1882
2512
3135
3764
5023
6293
7506
1004
612
529
1882
225
115
3764
450
231
6293
375
058
100
151
201
301
402
502
751
1005
1507
2009
2512
3014
4018
5023
6005
8025
1004
615
069
2009
230
139
3903
050
231
6004
6
96 144
192
289
385
481
722
964
1443
1923
2408
2887
3851
4809
5774
7679
9642
1443
419
226
2886
838
510
4809
557
737
-- -- -- 72 96 120
181
241
361
481
600
722
964
1201
1443
1923
2408
3609
4809
7217
9642
1200
914
434
-- -- -- -- -- 69 104
139
208
278
347
416
555
693
831
1109
1386
2079
2777
4163
5554
6928
8314
-- -- -- -- -- -- -- 80 120
161
200
241
321
401
481
641
803
1201
1605
2408
3210
4007
4809
-- -- -- -- -- -- -- -- 69 92 115
139
185
232
278
371
463
693
924
1391
1853
2315
2777
-- -- -- -- -- -- -- -- 63 84 105
125
167
209
251
335
419
629
837
1253
1674
2090
2512
-- -- -- -- -- -- -- -- -- -- 63 75 100
125
151
201
251
376
502
751
1005
1253
1507
-- -- -- -- -- -- -- -- -- -- -- -- 67 84 100
134
167
251
345
502
670
837
1005
Tran
s-fo
rmer
KV
A
Sec
on
dar
y S
ho
rt-C
ircu
it C
urr
ent
in A
mp
eres
*
Sec
on
dar
y V
olt
s
230
460
575
600
2400
4160
7200
12,4
7013
,800
23,0
0034
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Direct Current .............................................Page 112Alternating Current .....................................Page 112Sine Wave ..................................................Page 113Sinusodial Wave.........................................Page 113Instantaneous Current................................Page 113Peak Current ..............................................Page 113Average Current .........................................Page 113Effective Current.........................................Page 113RMS Current ..............................................Page 113Symmetrical Current...................................Page 114Asymmetrical Current.................................Page 114Offset Wave................................................Page 115Displaced Wave..........................................Page 115DC Component...........................................Page 115Total Current...............................................Page 115Decay .........................................................Page 115Decrement ..................................................Page 115Closing Angle .............................................Page 116
The introduction of direct current in analternating current analysis is done toprovide a relative comparison, to makethe understanding of alternating currenteasier.
Figure 1 represents steady current of10 amperes direct current. As can beseen, the DC value is constant and theoretically unaffected by time.
Almost everybody knows that alternatingcurrents vary or alternate continuously.They keep changing direction and varyin the value from 0 to Maximum back to0 in one direction and then repeating inthe opposite direction.
60 cycle AC currents change direction60 times per second and one cycle =1/60 second = 0.0167 second.
Random Closing.........................................Page 116Available Short-Circuit Current...................Page 116First Half Cycle Current..............................Page 116Current Limitation .......................................Page 117Melting Time ...............................................Page 117Arcing Time ................................................Page 117Total Clearing Time.....................................Page 117Let-Thru Current.........................................Page 117Triangular Wave .........................................Page 117Three-Phase Short Circuit..........................Page 117X/R Ratio ....................................................Page 118Impedance..................................................Page 118Phase Angle ...............................................Page 118Power Factor ..............................................Page 118I, I2 and I2t ...................................................Page 119Withstand Rating ........................................Page 120Interrupting .................................................Page 120
FERRAZ SHAWMUT
112
SHORT CIRCUIT LANGUAGE
It is impossible to discuss short-circuit currents without some understanding ofwhat happens during a short circuit and the terminology.
DIRECT CURRENT
ALTERNATING CURRENT
Figure 3
SINE WAVEAll the alternating current circuits which we will consider have currents and voltagesfollowing a sine wave. A sine wave is generated by a revolving vector, i.e. inside arotating machine.
SINUSOIDAL WAVESame as the Sine Wave.
EFFECTIVE CURRENTSince an alternating current varies continuously from 0 to maximum to 0 first in onedirection and then in the other, it is not readily apparent just what the true current valuereally is.The current at any point on a sine wave is called the INSTANTANEOUS CURRENT.The current at the top of the wave is called the PEAK or CREST CURRENT. It is alsopossible to determine the ARITHMETIC AVERAGE VALUE of the alternating current,but none of these values correctly relate alternating current to direct current. It is cer-tainly desirable to have 1 ampere of alternating current do the same work as 1 ampereof direct current. This current is called the EFFECTIVE CURRENT and 1 ampere ofeffective alternating current will do the same heating as 1 ampere of direct current.
RMS CURRENTEffective current is more commonly called RMS current. RMS means root mean squareand is the square root of the average of all the instantaneous currents squared.The RMS value of a sine wave is readily determined by calculus but can perhaps bemore easily understood by old-fashioned arithmetic. Let’s study a half sine wavehaving a 10 ampere maximum or peak value. The complete wave would be 20amperes (Fig. 4).
Figure 4
FERRAZ SHAWMUT
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FERRAZ SHAWMUT
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We will use instantaneous currents at10 degree intervals. The value of theinstantaneous currents can be easilymeasured. They have been tabulatedin the following table. These valueshave also been squared. The averageinstantaneous current and the averagesquared instantaneous current arefound by dividing the totals by 18. Thesquare root of the average squaredinstantaneous current is easily foundand readily understood.
Calculation of Average and RHS Currents
RMS = �50.0 = 7.07 amperes
The average current of sine wave is0.636 of the peak current and the effec-tive or RMS current is 0.707 of thepeak current
Putting this another way we can saythat the peak is 1.4 times the RMSvalue. Standard AC ammeters aremarked in RMS amperes and unlessstated otherwise all AC currents areconsiderd RMS currents.
When speaking of currents which flowfor a few cycles or less it is necessaryto specify what kind of amperes weretalking about such as:
RMS (effective)Peak (crest)AverageInstantaneous
The two currents shown above havethe same effective value.
SYMMETRICAL CURRENTA symmetrical current wave is symmet-rical about the zero axis of the wave.This wave has the same magnitudeabove and below the zero axis.
ASYMMETRICAL CURRENTAn asymmetrical current wave is notsymmetrical about the zero axis. Theaxis of symmetry is displaced or offsetfrom the zero axis, and the magnitudeabove and below the zero axis are notequal. See Figure 7.
0102030405060708090
100110120130140150160170180
01.743.425.006.437.668.669.409.86
10.009.869.408.667.666.435.003.421.740
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100.0097.2288.3675.0058.6741.3425.0011.703.030
Degrees
Instan-taneousAmperes
Instan-taneousAmperes Squared
Total 114.34 900.9Average 6.36 50.0
FERRAZ SHAWMUT
115
OFFSET CURRENTAn asymmetrical wave can be partiallyoffset. Fig. 7 shows a fully offset wave.Offset waves are sometimes calledDISPLACED WAVES.
DC COMPONENTThe axis of symmetry of an offset waveresembles a DC current and asymmet-rical currents can be readily handled ifconsidered to have an AC componentand a DC component. Both of thesecomponents are theoretical. The DCcomponent is generated within the ACsystem and has no external source.
Fig. 8 shows a fully offset asymmetri-cal current with a steady DC compo-nent as its axis of symmetry. The sym-metrical component has the zero axisas its axis of symmetry. If the RMS oreffective value of the symmetrical cur-rent is 1, then the peak of the symmet-rical current is 1.41. This is also theeffective value of the DC component.We can add these two effective cur-rents together by the square root of thesum of the squares and get the effec-tive or RMS value of the asymmetricalcurrent.
The RMS value of a fully offset asym-metrical current is 1.73 times the sym-metrical RMS current. It is readilyapparent that the peak asymmetricalcurrent is twice the peak symmetricalcurrent, i.e. 2 x 1.41 = 2.82
TOTAL CURRENTThe term total current is used toexpress the total or the sum of the ofthe AC component and the DC compo-nent of an asymmetrical current.
Total current and TOTAL ASYMMET-RICAL CURRENT have the samemeaning and may be expressed inpeak or RMS amperes.
DECAYUnfortunately fault currents are neithersymmetrical or fully asymmetrical butsomewhere in between. The DC com-ponent is usually short lived and is saidto decay.
In the above diagram the DC compo-nent decays to zero in about fourcycles. The rate of decay is calledDECREMENT and depends upon thecircuit constants. The DC componentswould never decay in a circuit havingreactance but zero resistance, andwould remain constant forever. In a cir-cuit having resistance but zero reac-tance the DC component would decayinstantly. These are theoretical condi-tions and all practical circuits havesome resistance and reactance, andthe DC component disappears in a few cycles.
FERRAZ SHAWMUT
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CLOSING ANGLEA short-circuit fault can occur at anypoint on the voltage wave of the cir-cuit. So far we’ve avoided discussingvoltage characteristics but the voltagewave resembles the current wave.The two waves may be in phase or outof phase and the magnitude and sym-metry of the current wave on a shortcircuit depends on the point of the volt-age wave at which the short occurs.
In laboratory tests it is possible to pickthe point on the voltage wave wherethe fault occurs by closing the circuit atany desired angle on the voltagewave. We can say that we pick theclosing angle to produce the currentconditions which we wish. This iscalled Controlled Closing.
RANDOM CLOSINGIn real life, faults occur at any andevery point on the voltage wave and ina laboratory this can be duplicated byclosing the circuit at random. This isknown as random closing. The follow-ing is true of a short circuit having neg-ligible resistance:
1.) If the fault occurs at zero voltage the current wave is fully asymmetrical,thus the maximum value of short-cir-cuit current is obtained.
2.) If the fault occurs at maximumvoltage the current wave is completelysymmetrical, and a minimum value ofshort-circuit current is obtained.
3.) Most natural faults occur some-where between these two extremes.
AVAILABLE SHORT CIRCUIT CURRENTThe first question which enters ourminds when we look at Fig 9. is justwhat is the current value of a wavewhich is neither symmetrical or asym-metrical, in other words, what is theavailable short-circuit current.Referring again to Fig. 9 we can saythat it is symmetrical after about 4cycles, and we can properly talk aboutthe available short-circuit current inRMS symmetrical amperes after theDC component becomes zero. Wecan also determine current at 1, 2, 3cycles of any other time after the shortcircuit started.
FIRST HALF CYCLE CURRENT The accepted practice is to use thecurrent which is available 1/2 cycleafter the short circuit starts. For a fullyoffset wave the maximum currentdoes occur at the end of the first halfcycle of time. Because this is the worstcase, we should determine the peakand RMS currents at this point. Sincethe DC component has already startedto decay, we cannot use the valuesshown in Fig. 8 where there is nodecay.
As already mentioned, the rate ofdecay depends upon the circuit con-stants. A study of actual circuits of 600volts or less indicates that the proper1/2 cycle value for the RMS asymmet-rical current is 1.4 times the RMS sym-metrical current, and the peak instan-taneous current is 1.7 times the RMSasymmetrical current.
1.7 x 1.4 = 2.4 RMS symmetrical current
FERRAZ SHAWMUT
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CURRENT LIMITATIONThe significant reduction of availableshort-circuit current, in a circuit, by useof a device that prevents this short-cir-cuit current from reaching its maxi-mum value, is called CurrentLimitation. Fuses which perform thisfunction are known as CurrentLimiting. Current Limiting fuses oper-ate in less than 1/2 cycle, thus inter-rupting the short-circuit current beforeit can achieve its maximum value. Theresultant reduction(refer to shadedsegment of Fig. 11) is substantiallyless than the maximum value of avail-able short-circuit current.
This figure shows the current-limitingaction of these fuses. The MELTINGTIME is the time required to melt thefusible link. The ARCING TIME is thetime required for the arc to burn backthe fusible link and reduce the currentto zero. TOTAL CLEARING TIME isthe sum of the melting and arcingtimes and is the time from fault initia-tion to extinction.
LET-THRU CURRENTThe maximum instantaneous or peakcurrent which passes through the fuseis called the let-thru current. Thisvalue can be expressed in RMSamperes also. The value of let-thrucurrent is used in determination ofelectrical equipment protection, asrequired by the NEC, Article 110-10and CEC 14-200.
TRIANGULAR WAVEThe rise and fall of the current througha current-limiting fuse resembles anisosceles triangle, and can beassumed to be a triangle without intro-ducing an appreciable error. Since thisis not a sine wave, cannot determinethe RMS value of the let-thru currentby taking .707 of the peak value as fora sine wave. Suffice to say that theeffective or RMS value of a triangularwave is equal to the peak value divid-ed by �3.
Irms = =
The let-thru current of a current-limit-ing fuse varies with the design,ampere rating and available short-cir-cuit current. Fuse manufacturers fur-nish let-thru curves for their varioustypes of current-limiting fuses.
THREE-PHASE SHORT CIRCUITSThree-phase short-circuit currents canbe determined exactly the same assingle-phase currents if we assumeone phase is symmetrical. The threephases each have different currentvalues at any instant. Only one can befully asymmetrical at a given time.This is called the MAXIMUM orWORST PHASE and its RMS currentvalue can be found by multiplying thesymmetrical RMS current by the prop-er factor. The currents in the threephases can be averaged and theA V E R A G E 3 - P H A S E R M SAMPERES can be determined by mul-tiplying the symmetrical RMS currentby the proper factor. The common fac-tor is 1.25 times the RMS symmetricalcurrent which corresponds with an8.5% power factor. The Short CircuitPower Factor Relationships tableincludes multiplying factors for variouspower factors.
I peak��
I peak
1.73
FERRAZ SHAWMUT
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X/R RATIOEvery practical circuit contains resis-tance (R) and inductive reactance (X).These are electrically in series. Theircombined effect is called IMPED-ANCE (Z). When current flows thru aninductance (coil) the voltage leads thecurrent by 90° and when current flowsthru a resistance the voltage and cur-rent are in phase. This means that Xand R must be combined vectorially toobtain impedance
The resultant � angle is between thevoltage and current waves and iscalled the PHASE ANGLE. The volt-age leads the current or the currentlags the voltage by an amount equal tothe phase angle.
The X/R value is determinant as tohow long a short-circuit current willremain on a circuit if uninterrupted byan overcurrent protective device.
POWER FACTORPower factor is defined as a ratio ofreal power (KW) to apparent power(KVA).
PF = =
KW are measured with a watt-meter.KVA are calculated with a voltmeterand ammeter readings since the volt-age and current waves may be inphase or out of phase.
Without going into a lot of detail, KWand KVA can be represented by aright angle relationship as shown:
The active current is in phase with thevoltage. The actual current, as read onan ammeter, lags the voltage by anamount equal to the phase angle.
Power Factor = cos �
X/R = tan �
The power factor is said to be 1 orunity or 100% when the current andthe voltage are in phase i.e. when � =0 degrees. (cos �° = 1). The powerfactor is 0 when � is 90 degrees. (cos90° = 0).
The X/R ratio determines the powerfactor of a circuit and the table on thenext page gives power factors for arange of X/R ratios.
KWKVA
Real PowerApparent Power
SHORT CIRCUIT POWER FACTOR RELATIONSHIPS
FERRAZ SHAWMUT
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The small triangle shows current andtime variation when a current-limitingfuse interrupts a high fault current.The current starts to rise but the fuseelement melts before the availablecurrent can get through. The currentdrops to zero in the duration markedas “time”. The peak of the triangleshows the peak current which the fuselets through. This current can also beexpressed in RMS amperes. It shouldbe noted that current-limiting fuseslimit both current and time. Currentlimiting fuses could be called time lim-iting fuses.
I2 is a measure of the MechanicalForce caused by peak current (lp).This is the electro-magnetic forcewhich mechanically damages busstructures, cable supports and equip-ment enclosures.
Squaring the available peak current ofthe circuit gives a very large number in comparison to the square of the peaklet-thru current of the current-limitingfuse. The difference in the size of thetwo squares (Fig. 15) illustrates thegreat difference in lp2 , or mechanicalforce, exhibited with or without a cur-rent-limiting fuse.
I2t is a measure of the heating effect orThermal Energy of a fault current. I2tuses RMS amperes instead of peakamperes, used for mechanical forces.The difference in size of the largecube-like figure and the small cube-like figure (Fig. 16) represents the dif-ference in heating effect between hav-ing and not having a current-limitingfuse in the circuit. I2t is a measure ofthe heating effect which burns off con-ductors such as pigtails in breakersand heater coils in motor controllers. Italso welds butt contacts in contactorsand breakers. I2t units are amperesquared seconds.
Short CircuitPower Factor
Percent
05
10203050
100
Short Circuit X/R Ratio
Infinite19.9749.95014.89903.17981.73210.0000
1.7321.5681.4361.2471.1301.0261.000
1.3941.3011.2291.1271.0661.0131.000
2.8282.6252.4552.1831.9781.6941.414
Maximum1 Phase RMSAmperes at1/2 Cycle
Average3 Phase RMSAmperes at1/2 Cycle
MaximumPeak
Amperes at1/2 Cycle
Multiplying Factor
FERRAZ SHAWMUT
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These values of Mechanical force (I2)
and Thermal Energy (I2t) are valuablein determining the protection of electri-cal equipment. At any point in a distri-bution system the equipment must becapable of handling the MechanicalForce and Thermal Energy available.Should these values exceed the capa-bilities of equipment, either the equip-ment must be reinforced or a current-limiting fuse used to reduce theamount of force and energy availableto the equipment. This is referred to inarticle 110-10 of the NEC and 14-200of the CEC.
WITHSTAND RATINGThe maximum specified value ofVoltage and Current that equipmentcan safely “handle” is known as its“WITHSTAND RATING”. As previouslyshown short-circuit current translatesinto Mechanical Force (I2) andThermal Energy (I2t) which candestroy equipment and create hazardous conditions. Therefore, forequipment protection, the Withstand Rating should never be less than theavailable short-circuit current at theequipment location. In reality suchconditions cannot always be avoided.Hence, the current-limiting ability offuses is utilized to reduce the short-circuit current of a value LESS THANthe equipment Withstand Rating.
INTERRUPTING RATINGThe maximum specified value ofshort-circuit current that a overcurrentprotective device (fuse or circuitbreaker) can safely open or clear isknown as its INTERRUPTING RAT-ING. For circuit beakers there arenumerous ratings ranging from 10,000up (i.e 10,000, 14,000, 22,000,42,000, 65,000 etc.) In the case ofmodern current-limiting fuses (ClassR,J and L) there is one rating 200,000amperes RMS. Older fuse types(Class H and K) have 10,000, 50,000or 100,000 ampere ratings.
The Interrupting Ratings of over-cur-rent protective devices must never beexceeded if serious damage is to beavoided. Hence, the used of One-Time or Renewable, 10,000 ampereClass H fuses can create serious con-cern. Extreme caution must be exer-cised so that there 10,000 ampere rat-ing is not exceeded. This problem iseliminated with the application of200,000 ampere rated fuses.
NOTE: For further detailed informa-tion regarding fuse back-up protectionof circuit breakers, and compliancewith the National Electrical Code andCanadian Electrical Code, refer to the Ferraz Shawmut application guide“Fuse Protection of Molded CaseCircuit Breakers”.
FERRAZ SHAWMUT
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GLOBAL ELECTRICAL SYSTEMSAND STANDARDS FOR FUSES
As electrical markets expand internationally, worldwide voltagesand frequencies are of interest as well as the standards for prod-ucts.
For fuses, the most important standard is the harmonized IEC269,adopted by the European community and becoming recognizedworldwide. In North America the harmonized CANENA Standard248 has been accepted by the U.S., Canada and Mexico and mayeventually include Central and South America. CANENA Standard248 Class J and Class L fuses are now a part of IEC269, hencethey are available for use in countries adopting IEC standards andincluding them in their local standards.
Local fuse standards still exist. Examples are:
U.S. -- UL 248 France -- NFC 60.269Canada -- CSA C22.1-98 Germany -- DIN 57636 & VDE 0636Mexico -- NOM J-9 Spain -- UNE 21.103United Kingdom -- BS88 Australia -- AS 2005
Country domestic voltages and frequencies:
100 - 120 Volts/60 HzNorth America, Brazil, Venezuela, Columbia, Ecuador,
Peru, Northern Caribbean Islands, (Cuba, Haiti, DominicanRepublic, Puerto Rico, Virgin Islands, Bahamas), LiberiaPhilippines, Taiwan and South Korea)
100 Volts / 50 & 60 HzJapan
127 Volts / 50 & 60 HzMexico
220 - 240 Volts / 50 HzMost of the rest of the world
FERRAZ SHAWMUT
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1.0 GENERALThe electrical contractor shall furnish and install a complete set of fuses for allfusible equipment on the job as specified by the electrical drawings. Final testsand inspections shall be made prior to energizing the equipment. This shallinclude tightening all electrical connections and inspecting all ground conductors.Fuses shall be as follows:
2.0 MAINS, FEEDERS AND BRANCH CIRCUITSA. Circuits 601 to 6000 amperes shall be protected by current-limiting FerrazShawmut Amp-Trap 2000 Class L time-delay A4BQ fuses. Fuses shall be time-delay and shall hold 500% of rated current for a minimum of 4 seconds, clear 20times rated current in .01 second or less and be UL listed and CSA certified withan interrupting rating of 200,000 amperes rms symmetrical.
B. Circuits 600 amperes or less shall be protected by current-limiting FerrazShawmut Amp-Trap 2000 Class RK1 time-delay A2D (250V) or A6D (600V) orClass J time-delay AJT fuses. Fuses shall hold 500% of rated current for a min-imum of 10 seconds (30A, 250V Class RK1 case size shall be a minimum of 8seconds) and shall be UL listed and CSA certified with an interrupting rating of200,000 amperes rms symmetrical.
C. Motor ProtectionAll individual motor circuits shall be protected by Ferraz Shawmut Amp-Trap2000 Class RK1, Class J or Class L time-delay fuses as follows:
For circuits up to 480A Class RK1 - A2D (250V) or A6D (600V) or Class J - AJTFor circuits over 480A Class - A4BQ
Fuse sizes for motor protection shall be chosen from tables published by FerrazShawmut for the appropriate fuse. Heavy load and maximum fuse ratings arealso shown for applications where typical ratings are not sufficient for the startingcurrent of the motor.
D. Motor ControllersMotor controllers shall be protected from short circuits by Ferraz Shawmut Amp-Trap 2000 time-delay fuses. For IEC style controllers requiring Type 2 protection,fuses shall be chosen in accordance with motor control manufacturers’ publishedrecommendations, based on Type 2 test results. The fuses shall be Class RK1A2D (250V) or A6D (600V) or Class J AJT or Class CC ATDR (600V.)
SUGGESTED FUSESPECIFICATIONS
FERRAZ SHAWMUT
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E. Circuit breakers and circuit breaker panels shall be protected by FerrazShawmut Amp-Trap 2000 Fuses Class RK1 (A2D or A6D), Class J (AJT) orClass L (A4BQ) sized in accordance with tested UL Series-Connected combina-tions published in the current yellow UL Recognized Component Directory.
F. Lighting and control circuits in the connected combinations show up to 600Vacshall be protected by Ferraz Shawmut Amp-Trap 2000 Class CC time-delayATDR fuses, sizes according to the electrical drawings.
3.0 SPARESSpare fuses amounting to 10% (minimum three) of each type and rating shall besupplied by the electrical contractor. These shall be turned over to the ownerupon project completion. Fuses shall be contained and catalogued within theappropriate number of spare fuse cabinets (no less than one), located per projectdrawings. Spare fuse cabinets shall be equipped with a key lock handle, bededicated for storage of spare fuses and shall be GSFC, as supplied by FerrazShawmut.
4.0 EXECUTIONA. Fuses shall not be installed until equipment is to be energized. All fuses shallbe of the same manufacturer to assure selective coordination.
B. As-installed drawings shall be submitted to the engineer after completion ofthe job.
C. All fusible equipment rated 600 amperes or less shall be equipped with fuseclips to accept Class RK1 or Class J fuses as noted in the specifications.
5.0 SUBSTITUTIONSFuse sizes indicated on drawings are based on Ferraz Shawmut Amp-Trap 2000fuse current-limiting performance and selectivity ratios. Alternative submittals tofurnish materials other than those specified, shall be submitted to the engineer inwriting two weeks prior to bid date, along with a short circuit and selective coor-dination study.
SUGGESTED FUSESPECIFICATIONS cont.
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FERRAZ SHAWMUT
126
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1 -
800
801
- 12
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01 -
160
016
01 -
200
020
01 -
250
025
01 -
300
030
01 -
400
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01 -
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01 -
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-3/4
10-3
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219
219
273
273
273
273
273
273
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22-
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51 63 63 76 89 114
127
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5/16 3/8
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7/16 1/2
3/4
3/4
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8 9 9 11 13 19 19 19 25 25
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FERRAZ SHAWMUT
127
DIMENSIONS OF FUSEHOLDERSFOR CLASS H, J, K, R, CC AND MIDGET FUSES
Outline Only - 1 Pole Shown
Fuse Voltage,Class and
Ampere Range
Length Overall
Width Overall
Height Overall
A B C
Inch MM Inch MM Inch MM250V Class R, K, H
0 - 3031 - 60
61 - 100101 - 200201 - 400401 - 600
600V Class R, K, H0 - 30
31 - 6061 - 100
101 - 200201 - 400401 - 600
Class J0 - 30
31 - 6061 - 100
101 - 200201 - 400 401 - 600
Class CC & Midget0 - 30
3.004.758.338.00
11.513.1
7.007.00
10.010.514.516.1
3.94.007.006.128.00
11.0
0.85
76120211203292333
178178254267368409
99102178156203279
22
1.251.461.683.003.504.00
1.631.632.103.003.504.00
1.291.652.313.004.004.00
3.04
3237437689
101
4141537689
101
33425876
101101
77
1.382.122.282.903.624.75
2.002.002.502.903.624.75
2.122.122.362.903.754.75
1.31
3554577492
120
5151647492
120
5454605195
121
33
FERRAZ SHAWMUT
128
FERRAZ SHAWMUT CLASS J & R FUSES
AMP-TRAP 2000� - Class J, 600 volts AC, Time Delay Fuses,200kA I .R. AJT (Amperes):Amperes: 1, 1-1/4, 1-1/2, 1-6/10, 1-8/10, 2, 2-1/4, 2-1/2, 2-8/10,3, 3-2/10, 3-1/2, 4, 4-1/2, 5, 5-6/10, 6, 6-1/4, 7, 8, 9, 10, 12, 15,17-1/2, 20, 25, 30, 35, 40, 45, 50, 60, 70, 80, 90, 100, 110, 125, 150, 175, 200, 225, 250, 300, 350, 400, 450, 500, 600
Amp-trap� - Class J, 600 volts AC, Non-Time Delay Fuses,200kA I .R. A4J (Amperes):Amperes: 1, 3, 6, 10, 15, 20, 25, 30, 35, 40, 45, 50, 60, 70, 80, 90,100, 110, 125, 150, 175, 200, 225, 250, 300, 350, 400, 450, 500, 600
Tri-onic� - Class RK5, Time Delay Fuses, 200kA I.R.TR (Amperes) R, 250 volts AC, TRS (amperes) R, 600 volts AC:Amperes: 1/10, 15/100, 2/10, 3/10, 4/10, 1/2, 6/10, 8/10, 1, 1-1/8, 1-1/4,1-4/10, 1-6/10, 1-8/10, 2, 2-1/4 2-1/2, 2-8/10, 3, 3-2/10, 3-1/2, 4, 4-1/2,5, 5-6/10, 6, 6-1/4, 7, 8, 9, 10, 12, 15, 17-1/2, 20, 25, 30, 35, 40, 45, 50,60, 70, 75, 80, 90, 100, 110, 125, 150, 175, 200, 225, 250, 300, 350, 400, 450, 500, 600
Amp-Trap� - Class RK1, Fast Acting Fuses, 200kA I.R.A2K (Amperes) R , 250 volts AC, A6K (Amperes) R,600 volts AC:Amperes: 1, 3, 4, 5, 6, 8, 10, 12, 15, 20, 25, 30, 35, 40, 45, 50, 60, 70, 80,90, 100, 110, 125, 150, 175, 200, 225, 250, 300, 350, 400, 450, 500, 600
AMP-TRAP� - Class RK1, Time Delay, 200kA I.R.A2D (Amperes) R, 250 volts AC, A6D (Amperes) R ,600 volts AC:Amperes: 1/10, 15/100, 2/10, 3/10, 4/10, 1/2, 6/10, 8/10, 1, 1-1/8, 1-1/4,1-4/10, 1-6/10, 1-8/10, 2, 2-1/4, 2-1/2, 2-8/10, 3, 3-2/10, 3-1/2, 4, 4-1/2, 5,5-6/10, 6, 6-1/4, 7, 8, 9, 10, 12, 15, 17-1/2, 20, 25, 30, 35, 40, 45, 50, 60,70, 75, 80, 90, 100, 110, 125, 150, 175, 200, 225, 250, 300, 350, 400, 450500, 600
AMP-TRAP 2000� family of fuses that can give “No-Damage” protection to equipment andelectrical systems. AJT provides both time and delay for motor loads and is suitable for theprotection of service entrance equipment, feeder circuits, and branch circuits serving bothmotor and non-motor loads. A4J fast acting fuse is suitable for protection of capacitors, cir-cuit breakers, panelboards and switchboards. AJT and A4J dimensions need approximately 45% less mounting space than Class RK5 or Class RK1. Class RK5 and RK1 whenused with Class R clips reject “Code” fuses which have lower interrupting rating.
FOR INNOVATIVE SOLUTIONS IN CIRCUIT PROTECTION CALL FERRAZ SHAWMUT.
FERRAZ SHAWMUT
129
FERRAZ SHAWMUT CLASS L & T FUSES
AMP-TRAP 2000� - Class L Fuses, 600 volts AC, 601 to 6000Amps, 4 Seconds Delay, 200A I.R.;500 volts DC, 601 to 3000Amps, 100kA I.R., CSA Certi f ied, UL ListedA4BQ (Amperes): (* Not CSA Cer t i f ied or UL L is ted)Amperes: 100*, 150*, 200*, 250*, 300*, 350* 400*, 450*, 500*, 600*, 601,650, 700, 750, 800, 900, 1000, 1200, 1350, 1400, 1500, 1600, 1800, 2000,2500, 3000, 3500, 4000, 5000, 6000
Amp-trap� - Class L Fuses, 600 volts AC, 4 Seconds Delay,200kA I.R., CSA Certi f ied, UL ListedA4BY(Amperes):(*Not CSA Cer t i f ied or UL L is ted)Amperes: 200*, 250*, 300*, 350*, 400*, 500*, 600*, 601, 650, 700,750, 800,801, 900, 1000, 1100, 1200, 1201, 1350, 1400, 1500, 1600, 1800, 2000, 2001,2500, 3000, 3001, 3500, 4000, 4001, 5000, 6000
Amp-trap� - Class L Fuses, 600 volts AC, 10 Seconds Delay,200kA I .R., 500 volts DC, 100kA I .R., CSA Certi f ied, UL ListedA4BT(Amperes): (*Not CSA Cer t i f ied or UL L is ted)Amperes: 200*, 250*, 300*, 350*, 400*, 500*, 600*, 601, 650, 700, 750, 800,900, 1000, 1100, 1200, 1400, 1500, 1600, 1800, 2000
Amp-trap� - Class T, Fast Acting Fuses,200kA I.R., CSA Certi f ied, UL ListedA3T(Amperes), 300 volts AC, 1 to 1200 Amps.A6T(Amperes), 600 volts AC, 1 to 800 Amps.Amperes: 1, 3, 6, 10, 15, 20, 25, 30, 35, 40, 45, 50, 60, 70, 80, 90, 100,110, 125, 150, 175, 200, 225, 250, 300, 350, 400, 450, 500, 600, 700,800, 1000, 1200
One Time Fuse: 1-600 Amps, 50KA I. R.,CSA Certi f ied CSA Type P” and UL ListedO T N 250 Volts AC,Amperes: 15, 20, 25, 30, 35, 40, 45, 50, 60,(For Canadian Market)O T(Amperes), 250 volts AC, OTS (Amperes), 600 volts ACAmperes: 1 , 2, 3, 4, 5, 6, 10, 15, 20, 25, 30, 35, 40, 45, 50, 60, 70, 80,90, 100, 110, 125, 150, 175, 200, 225, 250, 300, 350, 400, 450, 500,600
Class L is the extension to the Class J range for fuse ratings above 600 amperes.Class L fuses are primarily for main feeder protection.Class T fuse is a small dimension fuse which provides a high degree of current limi-tation. Class T fuses are fast acting, suitable for the protection of circuit breakers,loadcenters, panelboards, switchboards and metering centers.
FERRAZ SHAWMUT
130
FERRAZ SHAWMUT CANADIAN CODE & PLUG FUSES
One Time Fuse: 1-600 Amps, CSA Type “P” (NRN 15-60A),10,000A I. R., CSA CertifiedNRN (Amperes), 250 volts AC, NRS(Amperes), 600 volts ACAmperes: 1, 2, 3, 4, 5, 6, 10, 15, 20, 25, 30, 35, 40, 45, 50, 60, 70, 80, 90, 100,110, 125, 150, 175, 200, 225, 250, 300, 350, 400, 450, 500, 600
Time Delay Fuse: 15-600 Amps, CSA Type “D”,10,000A I. R. CSA CertifiedCRN(Amperes), 250 volts AC, CRS(Amperes), 600 volts ACAmperes: 1, 2, 3, 4, 5, 6, 10, 15, 20, 25, 30, 35, 40, 45, 50, 60, 70, 80, 90, 100,110, 125, 150, 175, 200, 225, 250, 300, 350, 400, 450, 500, 600
RENEWABLE FUSE:1-600 Amps, 10,000A I. R. CSA Certified & UL ListedRF(Amperes), 250 volts AC, RFS(Amperes), 600 volts ACAmperes: 1, 2, 3, 4, 5, 6, 10, 15, 20, 25, 30, 35, 40, 45, 50, 60, 70, 80, 90, 100,110, 125, 150, 175, 200, 225, 250, 300, 350, 400, 450, 500, 600
PLUG FUSECSA Certified Type “P” & Type “D”, 10kA I. R.Standard Type - Non-Time Delay, 125 volts AC: G (Amps)Amperes: 3, 6, 10Type “P” - Non Time Delay, 125 volts AC: GP(Amps)Amperes: 15, 20, 25, 30Type “D” - Time Delay, 125 volts AC: TD(Amps)Amperes: 15, 20, 25, 30Type GW - UL Listed Non-Time Delay, 125 volts AC: GW(Amps)Amperes: 3, 6, 10Type GTL - UL Listed Time Delay, 125 volts AC: GTL(Amps)Amperes: 15, 20, 25, 30Type GT - UL Listed Industrial time Delay with Thermal,125 volts AC: GT(Amps)Amperes: 15, 20, 25, 30Type GSL - UL Listed T-D Tamper Resistant, 125 Volts AC:GSL (Amps)Amperes: 15, 20, 25, 30Type G - UL Listed Non-Time Delay, 125 volts AC: G(Amps)Amperes: 3, 6, 10
GENERAL APPLICATIONS:
Note that the Canadian Electrical Code permits only Type “D” or Type “P” fuses for Cyclicalload applications in residential installations e.g. electric heating circuits.
FERRAZ SHAWMUT
131
FERRAZ SHAWMUT SEMICONDUCTOR FUSES
Form 101 Semiconductor Protection Fuses - 130, 250, 500, 600, 700,1000 and 1200 volts AC, 1 to 6000 Amps, 100kA I.R.Form 101 Amp-trap fuses are specially designed for the protection of semicon-ductors. They are fast acting fuses necessary to the protection of diodes andSCR’s or where a very fast acting characteristic is required.
FOR FUSE SUBSTITUTION PLEASE CONTACT FERRAZ SHAWMUT
Style CodeFast X or ZFaster, Lower I2t PFaster, lowest I2t Q or QS
Mounting Type CodeFerrule 1Ferrule with midgetdia. (1-1/2” x 13/32”) 2Blades, bolt-in 4Hockey puck 128
2 1, 2, 3, 4, 5, 6, 7, 8, 10, 12, 15, 20, 25, 30
1, 4* 35, 40, 45, 50, 55. 60
4 40, 50, 70, 80, 90, 100, 130, 150, 200, 250,300, 350, 400, 450, 500, 600, 800, 1000
128 1000, 1200, 1500, 2000, 2,500, 3000,3500, 4000, 5000, 6000,
1 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 12, 15, 20, 25, 30
35, 40, 50, 60, 70, 80, 90, 100, 125,4 130, 150, 175, 200, 225, 250, 300,
350, 400, 450, 500, 550, 600,
4,128 700, 800
128 1000, 1200, 1500, 1600, 2000,2500, 3000, 3500, 4000, 4500
1 10, 15, 25, 30
35, 40, 50, 55, 60, 70, 80, 90, 1004 125, 150, 175, 200, 225, 250, 275,
300, 325, 350, 400, 450, 500, 600700, 800, 900, 1000, 1200
40, 50, 60, 70, 80, 90, 100, 125, 150,4 175, 200, 225, 250, 300, 350, 400,
450, 500, 600
2 5, 8, 10, 12, 15, 20, 25, 30
1 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 12, 15, 20, 25, 30
40, 45, 50, 55, 60, 70, 80, 90, 100,4 125, 150, 175, 200, 225, 250, 300,
350, 400, 450, 500, 600
4,128 700, 800
128 1000, 1200, 1500, 1600, 1800, 200035, 40, 50, 70, 80, 90, 100, 125, 150,
4 175, 200, 225, 250, 300, 350, 400, 450, 500, 600, 700, 800, 900, 100035,40, 50, 60, 80, 90, 100, 125, 150,
4 175, 200, 250, 300, 350, 400, 450,500, 600
1 15, 20, 25, 30
35, 40, 50, 60,65, 70, 80, 100, 1254 150, 200, 225, 250, 300, 350, 400, 500
600, 650, 700, 800, 1000
1 1/2, 1, 2, 3, 4, 5, 6, 10, 15, 20, 25, 30
A13X(Amps) 130 VAC
CatalogueNumber
Voltage Rating Type Ampere Rating
A25X (amps)
A50P (amps)
A50QS (amps)
A60X (amps)
A70P (amps)
A70Q (amps)
A100P (amps)
A120X (amps)
250 VAC
500 VAC
500 VAC
600 VAC
600 Vac/DcA60Q (amps)
700 VAC
700 VAC
1000 VAC
1200 VAC
FERRAZ SHAWMUT
132
FERRAZ
CALL FERRAZ
FERRAZ SHAWMUT
133
FERRAZ
ASK FERRAZ
US3J/US6JFOR 30A & 60AClass J Fuses, 600 V ACUL Listed, CSA Certified
FERRAZ SHAWMUT
134
FERRAZ
CALL FERRAZ
FERRAZ SHAWMUT
135
20305203062030720308203152031620317203182035520326203272032820355203562035720358206052060620607206082065520656206572065821035210362103721038210052100621007210082200122003220512205324001240032405124053240312403324031240632631263326612663
30305R20306R20307R20308R20315R20316R20317R20318R20325R20326R20327R20328R20355R20356R20357R20358R20605R20606R20607R20608R20655R20656R20657R20658R21035R21036R21037R21038R21005R21006R21007R21008R22001R22003R22051R22053R24001R24003R24051R24053R24031R24033R24061R24063R2631R2633R2661R2663R
Adder123
Adder123
Adder123
Adder123
Adder123
Adder123
Adder123
Adder1231313131313131313
BoxSide-Clip
BoxSide-Clip
BoxSide-Clip
BoxSide-Clip
BoxIn-line Clip
BoxIn-line-Clip
BoxIn-line-Clip
BoxIn-line-Clip
Cu/Al#6 - 350 MCM
Cu#6 - 350 MCM
Cu/Al250 - 1000 MCM
Cu/Al250 - 1000 MCM
Cu/Al(2)#4 - 350 MCM
Cu(2)#6 - 350 MCM
Cu/Al(2)#4 - 500 MCM
Cu(2)#4 - 500 MCM
60305J60306J60307J60308J60315J60316J60317J60318J60325J60326J60327J60328J60355J60356J60357J60358J60605J60606J60607J60608J60655J60656J60657J60658J
—61036J61037J61038J
—61006J61007J61008J62001J62003J62051J62053J64001J64003J64051J64053J64031J64033J64061J64063J6631J6633J6661J6663J
60305R60306R60307R60308R60315R60316R60317R60318R60325R60326R60327R60328R60355R60356R60357R60358R60605R60606R60607R60608R60655R60656R60657R60658R61035R61036R
—61038R61005R61006R
—61008R62001R62003R62051R62053R64001R64003R64051R64053R64031R64033R64061R64063R6631R6633R6661R6663R
6030560306603076030860315603166031760318603256032660327603286035560356603576035860605606066060760608606556065660657606586103561036
—610386100561006
—610086200162003620516205364001640036405164053640316403364061640636631663366616663
Box
Box
Box
Box
Box
Box
PressurePlate
Screw30
60
100
200
400
600
Amp ConnectorWire Type/
GaugePoles
Standard (Code) Class R Class J
250 V 600 V 250 V 600 V 600 V
Cu/Al#14 - #2
Cu/Al#14 - #10
Cu/Al#14 - #10
Cu/Al#14 - #4
Cu/Al#14 - #2
Cu/Al#14 - #4
Cu/Al#6 - 2/10
Cu/Al#12 - 2/0
FERRAZ SHAWMUT FUSE BLOCKS
NEED APPLICATION ASSISTANCE?CALL FERRAZ SHAWMUT.
FERRAZ SHAWMUT
136
FERRAZ SHAWMUT FUSE BLOCKS
Fuse Blocks forMidget andClass CC Fuses600 volts, 30 AmpsCSA CertifiedUL listed or Recognized
Amp-trapForm 101Fuse Blocks
FEATURES� Accommodate Ferraz
Shawmut Form 101 Amp-trapclip and stud-mounted fuses.
� Plated clips and studs with mounting hardware included.
� Rated 1 to 600 amperes, 130thru 1200 volts
� UL Recognized, 1000 voltsAC and DC - Stud type.
� UL Recognized, 1200 voltsAC and DC - Clip type
Screww/doubleQuickConnects at both ends.
PressurePlatew/doubleQuickConnectsat both ends.
CopperBox
Cu#14to
#10
Cu#14to
#10
Cu#14to#6
Adder1234
Adder1234
Adder1234
3031030311303123031330314
3032030321303223032330324
3035030351303523035330354
30310R30311R30312R30313R30314R
30320R30321R30322R30323R30324R
30350R30351R30352R30353R30354R
Type Wire Poles Midget Class CC
1-3031-60
70-450500-600
1-3035-60
70-200225-600
10-3035-60
70-200225-600
5-30
1-3035-200
225-600
1-3035-100
125-400450-600
35-100124-400
1-30
3031160306JP243DP243G
20306P243GP243
P243G
20306P243GP243EP266C
30311
60306P243CP266A
20306P243CP266AP266F
P266GP266F
P292
A13X
A25X
A50P, A50QS
A60Q
A60X
A70P, A70Q
A100PA100P
A120X
For use with Amperes Cat. #
YOUR #1 FUSE COMPANY
FERRAZ SHAWMUT
137
AMP-TRAP� Type CS-3 Voltage 5.5kV
NumberE-Rating of Barrels Diameter Clip Centre5E - 65E 1 2” 12”
10E - 200E 1 3” 12”250E - 450E 2 3” 12”
AMP-TRAP� Type CS-3 Voltage 15.5kV
NumberE-Rating of Barrels Diameter Clip Centre5E - 30E 1 2” 15”10E - 50E 1 3” 15”65E - 100E 2 3” 15”65E - 100E 1 3” 18”125E - 200E 2 3” 18”
AMP-TRAP� Type CL-14 Voltage 5.5kV
Number E-Rating of Barrels Diameter Clip Centre
10E - 150E 1 3” 15.25”200E - 400E 1 3” 21.25”450E - 600E 2 3” 21.25”
AMP-TRAP� Type CL-14 Voltage 15.5kV
NumberE-Rating of Barrels Diameter Clip Centre10E - 50E 1 3” 18.25”65E - 100E 1 3” 18.25”
125E 2 3” 18.25”150E - 300E 3 3” 18.25”
AMP-TRAP� Type Bolt in Style Voltage 5.5kV
NumberE-Rating of Barrels Diameter Clip Centre
750E - 900E 3 3 “ 23,75”
FERRAZ SHAWMUT CAN HELP YOU COORDINATE YOUR MEDIUM VOLTAGE FUSES
FERRAZ SHAWMUT MEDIUM VOLTAGE“E” & “R” RATED FUSES
FERRAZ SHAWMUT
138
FERRAZ SHAWMUT MEDIUM VOLTAGE “R” RATED FUSES
FERRAZ SHAWMUT CAN HELP YOU COORDINATE YOUR MEDIUM VOLTAGE FUSES.
AMP-TRAP� R-Rated Ferrule Fuse 2.4kV
NumberR-Rating of Barrels Diameter Length2R - 12R 1 3” 10.88”18R - 24R 2 3” 10.88”
36R 3 3” 10.88”
AMP-TRAP� R-Rated Ferrule Fuse 4.8kV
NumberR-Rating of Barrels Diameter Length2R - 12R 1 3” 15.88”18R - 24R 2 3” 15.88”
36R 2 3” 15.88”
AMP-TRAP� R-Rated Ferrule Fuse 7.2kV
Number E-Rating of Barrels Diameter Length2R - 12R 1 3” 15.88”18R - 24R 2 3” 15.88”
AMP-TRAP� R-Rated Bolt in Fuse 7.2kV
NumberR-Rating of Barrels Diameter Length2R - 12R 1 3” 17.88”18R - 24R 2 3” 17.88”
FERRAZ SHAWMUT
139
FERRAZ SHAWMUT EUROPEAN DIMENSION FUSE-LINKS WITHFERRULE CONTACTS HIGH RUPTURING CAPACITY
Class gF ✝ Class gl-gG ✝
Sizes 6.3mm x 23mm 250VBreaking Capacity 6,000AAmperes: 2, 4, 6, 10.Sizes 8.5mm x 23mm 250VBreaking Capacity 6000A Amperes: 2, 4, 6, 10, 16.Sizes 10.3mm x 25.8mm 250V Breaking Capacity 6000AAmperes: 6, 10, 16.Sizes 8.5mm x 31.5mm 380VBreaking Capacity 20,000AAmperes: 0.5, 1, 2, 4, 6, 8, 10, 12,16, 20, 25.Sizes 10.3mm x 31.5mm 380VBreaking Capacity 20,000A Amperes: 6, 10, 25.Sizes 8.5mm x 36mm 380VBreaking Capacity 20,000AAmperes: 2, 4, 6, 10, 16, 20, 25,32.Sizes 10.3mm x 38mm 380VBreaking Capacity 20,000AAmperes: 25, 32.
✝ Also available with Indicator
Sizes 8mm x 31mm 400V Breaking Capacity 20,000A Amperes: .5, 1, 2, 4, 6, 8, 10, 12,16, 20, 25.Sizes 10mm x 38mm 500VBreaking Capacity 120,000A Amperes: .5, 1, 2,4, 6, 8, 10, 12,16, 20, 25, 32.Sizes 14mm x 51mm 660VBreaking Capacity 80,000A Amperes: 1, 2, 4, 6, 8, 10, 12,16, 20, 25.Sizes 14mm x 51mm 500VBreaking Capacity 120,000AAmperes: 32, 40.Sizes 14mm x 51mm 400VBreaking Capacity 120,000AAmperes: 50.Sizes 22mm x 58mm 660VBreaking Capacity 80, 000AAmperes: 2, 4, 6, 8, 10, 12, 16, 20,25, 32, 40, 50, 63, 80.Sizes 22mm x 58mm 500VBreaking Capacity 120,000AAmperes: 100.Sizes 22mm x 58mm 400V Breaking Capacity 120,00A Amperes: 125.
✝ Also Available with Indicator
CALL FERRAZ SHAWMUT FOR ALL YOUR FUSE REQUIREMENTS!
GLOBAL SOLUTIONS FOR FUSE PROTECTION!
FERRAZ SHAWMUT
140
Class aM ✝
Sizes 8mm x 31mm 400V ACBreaking Capacity 20,000AAmperes: 1, 2, 4, 6, 8, 10.
Sizes 10mm x 38mm 500V ACBreaking Capacity 120,000AAmperes: .16, .25, .5, 1, 2, 4, 6, 8, 10, 12, 16, 20.
Sizes 10mm x 38mm 400V ACBreaking Capacity 120,000AAmperes: 25.
Sizes 14mm x 51mm 660V ACBreaking Capacity 80,000AAmperes: .25, .5, 1, 2, 4, 6, 8, 10, 12, 16,20, 25.
Sizes 14mm x 51mm 500V ACBreaking Capacity 120,000AAmperes: 32, 40, 45.
Sizes 14mm x 51mm 400V ACBreaking Capacity 120,000AAmperes: 50.
Sizes 22mm x 58mm 660V ACBreaking Capacity 80,000AAmperes: 2, 4, 6, 8, 10, 12, 16, 20, 25,32, 40, 50, 63, 80.
Sizes 22mm x 58mm 500V AcBreaking Capacity 120,000AAmperes: 100.
Sizes 22mm x 58mm 400V ACBreaking Capacity 120,000AAmperes: 125
✝ Most types available with Indicator-Consult Ferraz Shawmut for details
FERRAZ SHAWMUT EUROPEAN DIMENSION FUSE-LINKSWITH FERRULE CONTACTS HIGH RUPTURING CAPACITY
Class gl-gGWith Str iker
Sizes 14mm x 51mm 500V ACBreaking Capacity 120,000AAmperes: 4, 6, 8, 10, 12, 16,20, 25, 32, 40
Sizes 14mm x 51mm 400V ACBreaking Capacity 120,000AAmperes: 50.
Sizes 22mm x 58mm 660V ACBreaking Capacity 120,000AAmperes: 4, 6, 8, 10, 12, 16, 20, 25, 32, 40, 50, 63
Sizes 22mm x 58mm 500V ACBreaking Capacity 120,000AAmperes: 125.
Class aMWith Striker
Sizes 14mm x 51mm 500V ACBreaking Capacity 120,000AAmperes: 1, 2, 4, 6, 8, 10, 12, 16, 20, 25, 32, 40, 45
Sizes 14mm x 51mm 400V ACBreaking Capacity 120,000AAmperes: 50.
Sizes 22mm x 58mm 660V ACBreaking Capacity 120,000AAmperes: 1, 2, 4, 6, 8, 10, 12, 16, 20, 25, 32, 40, 50, 63.
Sizes 22mm x 58mm 500V AcBreaking Capacity 120,000AAmperes: 80
Sizes 22mm x 58mm 500V ACBreaking Capacity 120,000AAmperes: 100, 125
FERRAZ SHAWMUTEUROPEAN DIMENSION
FUSE-LINKS
Cartr idge FuseNeozedType DO 400V AC/250V DC
Sizes DO1Amperes: 2, 4, 6,10, 13,16,
Sizes DO2Amperes: 20, 25,35, 50, 63.
Sizes DO3Amperes: 80, 100.
Cartr idge FuseDiazedType D 500V AC
Sizes DIAmperes: 2, 4, 6, 10, 16, 20, 25.
Sizes DIIAmperes: 2, 4, 6, 10,16, 20, 25.
Sizes DII IAmperes: 35, 50, 63.
Sizes DIVAmperes: 80, 100.
Sizes DVAmperes: 125, 160, 200
SEMICONDUCTOR NHFUSE-LINKS RECTICUR� “ULTRA-RAPID” TYPE aR
Size 00 500V ACBreaking Capacity 100,000AAmperes: 16, 20, 25, 32, 40, 50, 63, 80, 100, 125, 160.
Size 1 500V ACBreaking Capacity 100,000AAmperes: 16, 20, 25, 32, 40,50, 63, 80, 100, 125, 160,200, 250.
Size 2 500V AVBreaking Capacity 100,000AAmperes: 80, 100, 125, 160, 200, 250, 315, 400.
Size 3 500V AC Breaking Capacity 100,000AAmperes: 300, 315, 400, 500. 630.
Size 00 690V ACBreaking Capacity 100,000AAmperes: 25, 32, 40, 50, 63, 80A,100A, 125, 160.
FERRAZ SHAWMUT
141FERRAZ SHAWMUT IS QUALITY.
Size C00 500V ACBreaking Capacity 120,000AAmperes: 2, 4, 10, 16, 20,25, 32, 35, 40, 50, 63, 80, 100.
Size 00 500V ACBreaking Capacity 120,000AAmperes: 125, 160.
Size 0 500V ACBreaking Capacity 120,000AAmperes: 6, 10, 16, 20, 25, 32,35, 40, 50, 63, 80, 100, 125, 160200, 224, 250.
Size 1 500V ACBreaking Capacity 120,000AAmperes: 16, 20, 25, 32, 35, 40, 50, 63, 80, 100, 125, 160, 200, 224, 250.
Size 2 500V ACBreaking Capacity 120,000AAmperes: 25, 35, 40, 50, 63, 80, 100,125, 160, 200, 224, 250, 300,315, 355, 400, 425.
Size 3 500V ACBreaking Capacity 120,000AAmperes: 224, 250, 300, 315, 355, 400, 425, 500, 630.
Size 4 500V ACBreaking Capacity 120,000AAmperes: 500, 630, 800, 1000, 1250.
Size 4A 500V ACBreaking Capacity 120,000AAmperes: 500, 630, 800, 1000, 1250.
Size C00 690V ACBreaking Capacity 120,000AAmperes: 2, 4, 6, 10, 16, 20,25, 32, 35.
Size 00 690V ACBreaking Capacity 120,000AAmperes: 40, 50, 63, 80, 100.
Size 1 690V ACBreaking Capacity 100,000AAmperes: 16, 20, 25, 32, 35, 40, 50, 63, 80, 100, 125, 160, 200A.
Size 2 690 AC Breaking Capacity 100,000AAmperes: 35, 40, 50 63, 80,100, 125, 160, 200, 224, 250, 315.
Size 3 690V AC Breaking Capacity 100,000AAmperes: 250, 315, 355, 400, 500.
Size 4 690V ACBreaking Capacity 100,000AAmperes: 400, 500, 630, 800.
Size 4A 690V ACBreaking Capacity 100,000AAmperes: 400, 500, 630,800.
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FERRAZ SHAWMUT EUROPEAN DIMENSION FUSES
Type NH Knife Fuse-LinksHigh Rupturing Capacity
gL-gG
NEED TO PROTECT YOUR INVESTMENT. CALL FERRAZ SHAWMUT
FERRAZ SHAWMUT
143
FERRAZ SHAWMUT EUROPEAN DIMENSION FUSESNH Type Knife Fuse-Links - High Rupturing Capacity
aM
Size C00 500V ACBreaking Capacity 120,000AAmperes: 2, 4, 10, 16, 20,25, 32, 35, 40, 50, 63, 80.
Size 00 500V ACBreaking Capacity 120,000AAmperes: 100, 125, 160.
Size 0 500V ACBreaking Capacity 120,000AAmperes: 16, 20, 25, 32, 35, 40,50, 63, 80, 100, 125, 160.
Size 1 500V ACBreaking Capacity 120,000AAmperes: 16, 20, 25, 32, 35, 40, 50,63, 80, 100, 125, 160, 200, 250.
Size 2 500V ACBreaking Capacity 120,000AAmperes: 32, 35, 40, 50, 63, 80, 100,125, 160, 200, 224, 250, 315, 400.
Size 3 500V ACBreaking Capacity 120,000AAmperes: 315, 355, 400, 500, 630.
Size 4 500V ACBreaking Capacity 120,000AAmperes: 630, 800, 1000, 1250
gTrTransformer Fuse Links
Size 2 400V ACBreaking Capacity 100,000AAmperes: 100kVA 145A,125kVA 181A, 160kVA 231A,200kVA 289A, 250kVA 361A
Size 3 400V ACBreaking Capacity 100,000AAmperes: 250kVA 361A,315kVA 455A, 400kVA 578A
Size 4A 400V ACBreaking Capacity 100,000AAmperes:100kVA 145A, 125kVA 181A,160kVA 231A, 200kVA 289A,250kVA 361A, 315kVA 455A,400kVA 578A, 500kVA 723A,630kVA 910A, 800kVA 1155A
NEED SOFTWARE TO DO YOUR COORDINATION AND SHORT CIRCUIT ANALYSIS.CALL FERRAZ SHAWMUT
Class gl-gL-gG with Striker
Size 0 660VBreaking Capacity 80,000AAmperes: 32, 35, 40, 50, 63, 80, 100.
Size 0 500VBreaking Capacity 120,000AAmperes: 125, 160, 200.
Size 1 660VBreaking Capacity 80,000AAmperes: 80, 100, 125, 160, 200.
Size 1 500VBreaking Capacity 120,000AAmperes: 224, 250, 315, 355.
Size 2 660VBreaking Capacity 80,000AAmperes: 125, 160, 200, 224,250, 315, 355.
Size 2 500V Breaking Capacity 120,000AAmperes: 400, 500,
Size 3 660V Breaking Capacity 80,000AAmperes: 315, 335, 400, 500.
Size 3 500VBreaking Capacity 80,000AAmperes: 630.
Class aM with Striker
Size 0 660VBreaking Capacity 80,000AAmperes: 32, 40, 50, 63, 80, 100,125, 160.
Size 0 500VBreaking Capacity 80,000VAmperes : 200
Size 1 660VBreaking Capacity 80,000AAmperes : 80, 100, 125, 160, 200, 250.
Size 1 500VBreaking Capacity 80,000AAmperes: 315.
Size 2 660VBreaking Capacity 80,000AAmperes: 125, 160, 200, 250, 315,355, 400.
Size 2 500VBreaking Capacity 80,000AAmperes: 500.
Size 3 660VBreaking Capacity 80,000AAmperes: 315, 355, 400, 500,
Size 3 500VBreaking Capacity 80,000AAmperes: 630.
FERRAZ SHAWMUT
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CALL FERRAZ SHAWMUT FOR ALL YOUR FUSE REQUIREMENTS. WHATEVER YOUR NEED FERRAZ SHAWMUT HAS A SOLUTION.
FERRAZ SHAWMUT EUROPEAN DIMENSION FUSESType NH Knife Fuse-Links - High Rupturing Capacity
FERRAZ SHAWMUT
145
Alternating current formulae, 49 - 50Aluminum and copper, comparative
weights of cables, 21Ambient temperature, definition, 8Ampere, correction factors, 56; definition, 4;
formulae for determining, 51; for one K.W.at various voltages and power factors, 72,73; ratings for various type motors, 54, 55;ratings for slip ring motors, 56; ratings ofsynchronous motors at full load, 57
Angle closing, 116Appliances, approximate cost of operating, 79Application of Power Factor Capacitors, 64
Belting, 104, 105
Cables, resistance and weights, 20 - 22Calculations, short circuit, 106 - 110Canadian Electrical Code Tables, 25 - 32Capacitors, power factor, application of, 64Catalog guide, Shawmut fuse data, 128 - 144Centigrade comparison with fahrenheit, 80Characteristics of transformers, 111Circles areas and circumferences, 87Circuit breaker, definition, 15Circular Mil, Definition, 19Closing angle, 116; random, 116Conductors, in conduit or tubing, 95; physical
properties of common electrical conductors,92 - 94; voltage drop, tables, 39 - 48
Conduit, dimensions and weights, 96;elbows, dimensions, 97; number of conductors in conduit or tubing, 95; percentarea of conduit or tubing, 95; conduit fill,calculation, 95; bushings and locknuts,dimensions, 97
Contact, definition, 15Contractor, definition, 17Controller, electric definition, 17Control Circuit Transformers, 71Conversion table general, 81 - 82; Kva to
amperes, 72Connection diagrams, transformers, 74 - 76Copper, aluminum, comparative weights
of, 21Copper wire information, formulae, 19 - 20;
resistance - temperature, 20Copper conductivity of, 19
Correction table for three-phase inductionmotors, power factor, 56
Cubes of numbers, 85 - 86Current, RMS, 113; available short circuit,
116; first half cycle, 116; let-thru, 117,effective, 113; line 45 - 47; symmetrical,114; asymmetrical, 114; offset, 115;total, 115
Decimal and metric equivalents of part of an inch, 84
Decimal equivalent, squares, cubes, squareroots, cube roots, circumference, areas ofcircles, 85 - 86
Definitions, general, 4 - 17Dimensions of fuses, 124 - 126; fuse
holders, 127Direct current generators, 63Drill sizes, 100; tap sizes, 99Drip-proof, definition, 16Dust-proof, definition, 16
Efficiencies of motors, 54 Electrical symbols for plans, 77 - 78Electrical metallic tubing, 96 - 97
Fahrenheit, comparison with Centigrade, 80Ferrule Fuses, 39 - 141Field current in D.C. generators, 63Formulae, alternating current, 49 - 51;
amperes, determining, 49; horsepower,electrical, 51; Kilowatts, 51; KVA, 51;reactance and resistance, 50; trigonomet-ric, 89 - 90
Fuse, cable protector, definition, 13; currentlimiting, 12; Class J, definition, 14; ClassK definition, 14; Class L, definition, 14;Class R definition, 14; ampere rating, 14;definition, 11; dimensions, 124 - 125;semiconductor, definition, 12; renewable,definition, 12; time-delay, definition, 12;welder protector, definition, 13; FerrazShawmut fuses, 128 - 144; secondary, 68;primary, 69 - 70
Fuseholders, dimensions, 127,Ultrasafe,133
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IndexGas-proof, definition, 16Gas-tight, definition, 16Generators and motors, D.C. generators,63;
synchronous speeds, A.C., 58Glass Fuses, miniature, 134Graphic symbols, 77 - 78
Hardness, conversion table, 98Hertz, (frequency) definition, 4Horsepower, electrical, formula for, 51
I, I2 and I2t, 119 - 120Identification of motors, 53Interrupting capacity or range definition, 8Iron, sheet metal gauge, 101
Kilowatt, KVA, formula for, 51; KVA conver-sion to amperes, 51
Language, short circuit, 112Line current and voltage drop, formulas
45 - 50Low voltage fuses, 59
Measures, tables of weights, 83Metals, weights of various, 91; gauge sheet,
101; hardness, 98Metric equivalents of parts of an inch, 84Midget fuse dimensions, 124Mil, circular, 19Moisture, resisting, definition, 16Molded-case, circuit breaker, definition, 15Motor overcurrent protection, 52Motors, alternating current motor fuse
table, 230-volt three-phase, 60; 480-volt three-phase, 61; 575-volt three-phase, 62, 115 - 230-volt single-phase, 59; ampere ratings of 220-volt induction motors, 56; ampere ratings of synchronous motors at fullload, 57; determining size of fuse for motors,60 - 62; efficiency and power factor values,54, protection automatic, 52; identificationof motors, 53
National Electric Code Tables, 23 - 24NH Fuse Links, 142 - 144
Ohm, definition, 4Ohm’s law, 37Operating cost of electrical appliances, 79Overcurrent protection of motors, 60 - 62
Physical and mechanical properties of metals, comparative, 92 - 93; hardness,98
Pipe, dimensions, 96; carrying capacity, 95Power factor correction table, 65 - 66;
application of, 64; short-circuit relation-ships, 119; general, 118
Protection of overcurrent motors, 52;transformers, 67
Pulleys, 102
Random, closing, 116Ratings (circuit breaker or switch), defini
tion, 15; continuous, definition, 7; inter-rupting, 120; withstand, 120; short-time,definition, 8
Ratio, current, definition, 11; marked defini-tion, 11, voltage definition, 11
Reactance, 49 - 50Relay, definition, 17Resistance, materials, properties of com-
mon, 94, ratio to reactance, formula for combining, 49 - 50
Rheostat, definition, 17
Screw threads, American national, coarseand fine, 99
Shafting, 103Shawmut, catalog guide, 128 - 144Sheet metal gauge, 101Short-circuit cable, 33 - 36Short-circuit calculations, 106 - 110Short-circuit currents, general 112 - 120Short-circuit power factor relationships, 119Short-circuit factors, 107 - 110Skin effect, 18Sleet-proof, definition, 16Specifications for Shawmut fuses,
suggested, 122- 123Splash-proof, definition, 16Squares and square roots of numbers,
85 - 86
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IndexSubmersible, definition, 16Switch auxiliary, definition, 17; control defini-
nition, 17; disconnecting, definition,17;master, definition, 17
Symbols for electrical plans, 77 - 78Synchronous motor ampere ratings, 57Synchronous speeds, A.C. generators and
motors, 58
Taps, drill sizes, 99Temperature, ambient, definition, 8;
comparison of Centigrade and Fahrenheit,80; coefficient, 19, 92, 94; resistancecorrection factor, 20
Tensile strength 93, 94, 98,Thermometers, Centigrade and Fahrenheit,
80Threads, screw, American, 99; pipe, 96Transformers, characteristics, 111, connec-
tion diagrams, 74 - 76; current definition,11; instrument, definition, 11; potential,definition, 10; short circuit currents 111
Trigonometric formulae, 89 - 90; functions,88
Tubing, electrical metallic, 96 - 97
Ultrasafe Fuse Holders, 133U.S. screw threads, 99
Voltage drop, 37 - 48
Wave, sine, 113; sinusoidal, 113; triangular117
Weights, general weights and measures, 83;iron and steel sheets, 101; stranded cop-per cable, 21 - 22; stranded copper and aluminum, comparison, 21 - 22; varioussubstances and metals, 91
Wire calculations, 37 - 38Wires and cables, data and applications,
19 -20; sizes for conduit, 95; strandedcopper, resistance and weight of, 21 - 22
Wiring, connection diagrams fortransformers, 74 - 76