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DOCUMENT RESUME
ED 265 369 CE 043 341
TITLE Basic Electricity in Agricultural Mechanics.INSTITUTION Montana State Univ., Bozeman. Dept. of Agricultural
and Industrial Education.SPONS AGENCY Montana State Office of Public Instruction, Helena.
Dept. of Vocational Education Services.PUB DATE Jul 85NOTE 191p.PUB TYPE Guides - Classroom Use - Guides (For Teachers) (052)
EDRS PRICE MF01/PCC8 Plus Postage.DESCRIPTORS *Agricultural Education; *Agricultural Engineering;
Behavioral Objectives; *Classroom Techniques; CourseContent; Course Organization; Electric Circuits;*Electricity; Equipment; *Hand Tools; LearningActivities; Lesson Plans; Safety; SecondaryEducation; *Teaching Methods; Transparencies; Unitsof Study; Vocational Education
IDENTIFIERS Montana
ABSTRACTThis unit of instruction on electricity has been
designed especially for teachers to use with freshmen and sophomorevocational agricultural students in Montana. It consists of anoutline of the unit and eight lesson plans. The unit outline liststhe following components: situation, aims and goals, lesson plans,student activities, teacher activities, and references. The eightlessons cover these topics: what electricity is; understandingelectrical terms and symbols; safety practices; electricity fromplant to farm; electrical tools, materials, and controls; types ofelectrical circuits; practical wiring applications; and crlculatingamps, volts, resistance, and cost of electrical power. Each lessoncontains some or all of the following parts: need for the lesson,objectives, interest approach, teaching plan, association andfollow-up, references, handouts, and transparency masters. (KC)
************************************************************************ Reproductions supplied by EDRS are the best that can be made ** from the original document. *
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fr457 3 3
BASIC ELECTRICITYIN AGRICULTURAL. MECHANICS
141%6
4 II ;11 Agricultural & trial Education, Montana State University, BozemanEDUCATION
1984 Revision
U
U.S. DEPARTMENT OF EDUCATIONNATIONAL INSTITUTE OF EDUCATION
EDUCATIONAL RESOURCES INFORMATIONCENTER (ERIC)
' This document has been reproduced asreceived from the person or organizationonginating it
ill Minor changes have been made to improvereproduction quality
Points of view or opinions stated in this docu
moot do not netesstuay represent official NIEposition or poky
1.
"PERMISSION TO REPRODUCE THISMATERIAL HAS BEEN GRAVED BY
"A 7
a
TO THE EDUCATIONAL RESOURCESINFORMATION CENTER (ERIC)."
O
BASIC ELECTRICITY INAGRICULTURAL MECHANICS
The work presented herein was supportedby the Office of Public InstructionDepartment of Vocational Education
Services
Montana State UniversityDepartment of Agricultural & Industrial Education
Room 126, Cheever Hall, Bozeman, MontanaJuly, 1985
3
I
TABLE OF CONTENTS
Lesson
What is Electricity - The Electron Theory
Understanding Electrical Terms and Symbols
Safety Practices to Prevent Electrical Accidents
Electricity From Plant to Farm
Electrical Tools, Materials and Controls
Types of Electrical Circuits
Practical Wiring Applications
Calculating Amps, Volts, Resistance, and Costof Electrical Power
Page
1
4
7
10
14
20
24
27
Forward
This unit of instruction has been designed especially foruse with freshman and sophomore vocational agriculture students.For your convenience, the material has been prepared to fit intoa three ring, loose-leaf notebook. Other material that isprepared to accompany this unit of instruction will be preparedin a similar manner.
The instructor should study the entire unit carefully beforeattempting to teach any of the lessons. The key concepts thatshould be presented to meet the objectives of the Montana corecurriculum are included; however, all material that would beapplicable may not be provided. Each instructor should look forways to incude local examples where possible and appropriate.
Some handouts and 'visual materials are included with eachlesson. Here again, each teacher may have additionalillustrative material that would be appropriate. It is alsoimportant that all references listed at the end of each lesson beavailable for the students to use at all times. The lessoncontent is based on the references listed.
Special thanks is given to Mr. Jim Larson, VocationalAgriculture Instructor, Custer High School, Custer, Montana whoprepared the initial material included in this unit ofinstruction-
ii5
UNIT PLAN
UNIT: Basic Electricity in Agricultural Mechanics
Situation:
All producers and agribusiness owners and managers use elec-trical energy in their business. Hardly a day will go bywithout almost every employer or employee using electricalenergy in one way or another. In the future, more ratherthan less electrical energy will be used.
A basic understanding of electricity will be valuable toanyone using this Source of energy. Such knowledge andskill will help a person use electricity more efficientlywhile conserving energy.
Aims and Goals:
1. To define the common terms a layman should know whenworking with electrical power.
2. To describe how electricity is produced.
3. To perform the mathematical calculations needed tomeasure electrical energy.
4. To demonstrate the ability to perform the basic skillsneeded to utilize electricity.
5. To calculate electrical costs.
6. To demonstrate a basic knowledge of electrical safety.
Lessons:
1. What is Electricity and the Electron Theory?
2. Understanding Electrical Terms and Symbols.
3. Safety Practices Used with Electricity
4. Electricity from Generating Plant to the Farm.
5. Electrical Tools, Equipment, Wire and Controls.
6. Types of Electrical Circuits.
7. Practical wiring Applications.
8. Calculating Electricity Using Ohm's Law.
iii
Student Activities:
1. Prepare a cross-word puzzle using electrical terms.
2. Wire series and parallel circuits.
3. Complete wiring diagrams.
4. Calculate the cost of electrical energy.
5. Identify electrical tools and wiring material.
6. Wire electrical switches and outlet
Teacher Activities:
1. Arrange for a field trip to an electrical generatingplant.
2. Order film and reference material relating to electricalpower.
3. Prepare a variety of wiring diagrams for class use.
4. Gather electrical supplies needed to complete studentexercises.
5. Build wiring boards as needed.
References:
Turner, Howard J., Understanding Electricity and ElectricalTerms. American Association for Vocational InstructionalMaterials, Athens, Georgia, 1981
Mix, Floyd M., House Wiring Simplified, Goodheart WillcoxCo., Inc., South Holland, Illinois.
Cobin, Thomas, Maintaining the Lighting and Wiring System,American Association for Vocational InstructionalMaterials, Athens, Georgia, 1980.
Parady and Turner, Electric Energy, American Associationfor Vocational Instructional Materials, Athen, Georgia,1976.
Calvin, Thomas, Electrical Wiring( Student Handbook,American Association for Vocational InstrucitonalMaterials, Athens, Georgia, 1983.
, Agricultural Wiring Handbook,AgriculturalMaTketing Division, Edison Electric Institute, 90 ParkAvenue, New York, NY, 10016.
, Maintaining the Lighting and Wiring System,(Transparency Masters), American Association for Voca-tional Instructional Materials, Athens, Georgia.
iv
UNIT: Basic Electricity
Lesson 1: What is Electricity and the Electron Theory?
Need:
The more a person knows about electricity, the more he/sheappreciates the importance of this source of power. Also,and understanding of electricit will help one understandtie advanced applications of electrical power.
Objectives:
1. Following this lesson, each student will be able toexplain what electricity is and how it travels from oneplace to another.
2. Using the electron theory, diagrams, and charts eachstudent will be able to discuss how protons and elec-trons produce electricity.
3. Following this lesson, the student will be able toidentify the methods of producing electricity whichinclude steam generators, water generators, and nucleargenerators.
Interest Approach:
Ask each student to draw what electricity looks like. Handout a piece of cord wire to each student and ask each toidentify the electricity in the wire. Now discuss - "Whatis electricity?" How does it get from point A to Point B.
Key questions, problems Teaching techniques andconcerns information
1. What is electricity? a. It is a convenient & controllableform of energy used to produceheat, light, and power.
b. It is electrons flowing from oneatom to another. (refer todefinitions page for electronand atom;
2. What is an atom? a. Atoms are made up of electronsand protons.
b. Protons cluster together to formtne nucleus of an atom. Each pro-ton has a (+) charge. The nucleusis the center of an atom.(OH-1)(OH'-2)
1
c. Electrons are negatively charged(-) and move at high speeds inorbital layers around the nucleus.(OH-3)
d. The electrons are kept in thoseorbits because protons attract orpull them. (OH -4)
3. What is a neutral atom? a. Atoms which contain exactly thesame number of electrons and pro-tons are called neutral atoms.
4. What are conductors? a. Conductors are mater...als whichallow electrons to move freely.Examples are copper, aluminum,silver and most other metals.
5. Why is copper a good a. Copper has 29 protons and 29conductor? electrons.
b. Electrons in the outer layer are
6. How is electricityproduced?
not held nearly as tightly asthose in the inner layers, thusthey are jarred loose very easily.(OH-5)
c. If an electron gets loose from oneatom of copper and goes to anotherthen both atoms become unstable.
d. When these atoms are short elec-trons, they rob them from anelectron which has toomany.(OH-6)
e. Copper atoms can lose or gainelectrons very easily, thuscausing a chain reaction whichcauses a flow of electricity.
a. Electricity is produced by con-trolling the movement of theseelectrons along a conductor.
b. A generator is turned by someoutside force, such as steam orwater.(OH-7)
c. The generator forces electronloose from some atoms and forcesthem onto other atoms.
d. Electrons then begin to move alonga wire to fill the needs of thoseatoms left short of electrons.
2
e. The forced movement of electronsin one direction or another iswhat is known as a flow ofcurrent.
7. What are the ways in a. Electricity may be produced by:which electricity is generators turned by steam - usingproduced? some sort of fuel such as coal,
fuel or wood; generators turned bywater, generally called hydro-electric power; or generatorsturned by the use of nuclear power
Application and Followup:
1. Hand out a worksheet and have students identify the termsand explain how electricity is produced by completing thecharts.
References:
AAVIM, Understanding Electricity & Electrical Terms
3
THE PROTON
THE CENTER OF THE ATOM CONTAINS ONE
OR MORE PROTONS
PH-1
o
OH-2
'.NUCLEUS OF AN ATOM
PROTONS CLUSTER TOGETHER TO FORM THE NUCLEUS
OF AN ATOM12
ELECTRONS TRAVEL
ONE OR MORE ELECTRONS TRAVEL IN ORBIT AROUND
THE NUCLEUS OF AN ATOM 13
OH-14
PROTONS AND ELECTRONS
A NEUTRAL ATOM HAS EXACTLY AS MANY ELECTRONS
RE','OLVING AROUND THE NUCLEUS AS IT HAS PROTONS
IN THE NUCLEUS
OH-5
COPPER ATOM
THE ELECTRON IN THE OUTER ORBIT OF A COPPER
ATOM IS LOOSELY HELD,
ELECTRONS MOVE
IT IS POSSIBLE TO ROB SOME
ATOMS OF ONE OR MORE
ELECTRONS,:P.' , L.:l
0."
.1
0H-6
ELECTRONS CAN BE FORCED
ON CERTAIN ATOMS
er.k .x.;IA;
.
,,antaL a irll 0-tift.41,3 of:
TWO ATOMS MAY EXCHAIIGE ELECTRONS, BUT THERE IS STILL THE
SAME NUMBER OF ELECTRONS AS PROTONS. THE TWO ATOMS ARE
STILL IN BALANCE.
FLOW OF CURRENT
NEGATIVELY CHARGED(electron gain)
UPPER WIRE
011-7
GENERATOR
POSI ilVELY CHARGED(electron loss)
WHEN ELECTRONS ARE FORCED TO MOVE FROM ONE ATOM TO ANOTHER, THE
MOVEMENT IS KNOWN AS A "FLOW OF CURRENT."
UNIT: Basic Electricity
Lesson 2: Understanding Electrical Terms and Symbols
Need:
A basic understanding of the makeup of the atom is necessarybefore a student can understand electricity.
Objectives:
1. Without the aid of a reference, each student will be ableto write the correct definition for each of the followingterms: watts, volts, amperes, circuit, ohms, resistance,direct current, insulator.
2. Given a wiring diagram, each student will be able tocomplete the schematics using the correct electricalsymbols.
Interest Approach:
Run off copies of a wiring diagram or electrical plan for ahouse or your school and ask your students the followingquestions:1. How many outlets are in the plan?2. Where is the service entrance panel?3. Where is the range outlet located?Continue the discussion. Impress upon the students the needfor a good plan and being able to read the electrical symbolsthat are found on electrical plans.
Note: A good technique would be to assign each student oneor more terms, have them read about the term(s) and have themdefinite the term to the other members of the class.
Kel. questions, problemsconcerns
1. Define the followingterms:
d. Volts
Teaching techniques andinformation
a. A measure of electricalpressure.(OH-1)
b. Amps(amperec) b. A measure of electricalflow.(OH-2)
c. Ohms
4
c. A measure of electricalresistance.(OH-3)(OH-4)
18
d. Watts
e. Resistance
f. Circuit
g. Switch
h. Direct Current DC
i. Alternating Current AC
j. Insulator
2. What symbols are usedin a wiring diagram?
d. Tells how much electricityis being used.Kilowatt- 1000 wattsKilowatt hour- 1000 wattsused in one hour.Electricity is sold inthis unit.
e. Electrical friction ortendency of a conductor(wire) to keep electricityfrom passing through it.
f. A complete path forelectricity to follow.(OH -5)
g. A device for controllingthe flow of current in anelectrical circuit byopening and closing thecircuit.
h. Current which flow,: in onedirection only.(OH-6)
i. Electricity flows first inone direction and then theother. Each two reversalsof flow is called acyclie. The number ofcyc es/second is calledfrequency.
. Material which will notconduct electricity.
a. Hand out a copy of elect-rical symbols or use as anoverhead.
b. Hand out a copy of thehouse wiring diagram anddiscuss how the symbolsare used.
Application and Followup:1. Hand out a worksheet on definitions.
2. Hand out a copy of a wiring diagram which needs to becompleted.
3. Give a quiz over the definitions and symbols to checkstudents' progress.
4. Divide the class into groups and have them develop acrossword puzzle using electrical terms.
References
AAVIM, Understanding Electricity & Electrical TermsGoodheart/Wilcox, House Wiring Simplified
LCOMMON ELECTRICAL TERMS]
ELECTRICITY- LIGHT, HEAT, POWER
AMPERE (AMP)- RATE OF FLOW (WATER-GAL/MIN)
VOLT (V)- PRESSURE (LBS/SQ IN)
WATTS (W)- POWER (HP)
KILOWATT (KW)- 1000 WATTS
KILOWATT-HOUR (KWH)- 1000 WATTS USED INONE HOUR
WATTS= VOLTS X AMPS
WATTSATTSVOLTS VOLTS= WATTS
AMPS
21
WATER SYSTEM ELECTRIC CIRCUIT
PUMP
:....:
: .: : - V.. : ...... .....
PRESSURE(Gals. per Sq. Inch)
op- F4A
T fr/
V -":.....-::::. :.:
") 4':::.:......:::, . ................................................
..::::ii.- .1.01V WATER WHEEL TURNING:??::.:::::.S;:i:::::
:::::::.:.:::: RATE OF FLOW:::::;:..:::....... (Work Done)'.':*":::::%::1:.',::..::::::'::.:::::.
. ::-......: (Gel. per MInuterii..:::::::::..::::::::11:c.:.... ..--. ..... ..-..-.:-.-;. ...
'%:::.:::.:::::::::::::.:.:.:.:.:::.....:.:-:-::.::::::-:
..:1:::::::::11i:::::...:::'7:::::::::.::::;........: ..... -.: ..:.........:.....: . .... : ........:. ........... -:...-...:::::.::::.....:...::::.:::.:.::::.
GRAINMILL
FUSEUSE BOX
(Volts)
GROUND
voorre.40
22
NEUTRALBAR
SWITCHHOT WIRE
APPLIANCE
RATE OF FLOW(Amperes)
NEUTRAL WIRE
WATTS(Work Done)
23
0VOLTAGE IS A MEASURE OF ELECTRICAL
PRESSURE ON A CIRCUIT
AN AMMETER MEASURES THECURRENT (ELECTRON) FLOW IN A CIRCUIT
2b
OH-6
ALTERNATING AND DIRECT CURRENT
DIRECT CURRENT
VOLTS
TIME
ALTERNATE CURRENT
28
TIME
HANDOUT #1
ELECTRICAL SYMBOLS
Electrical symbols, Fig. 9-5, are the electrician's system of "shorthand." Theyprovide a simple way to show on building plans, the electrical service to be provided,and where outlets and switches are to be installed. The use of electrical symbols isshown in Fig. 9-6.
CEILING OUTLETSFOR FIXTURES
WALL FIXTURE OUTLET
CEILING OUTLET WITHPULL SWITCH
WALL OUTLET WITHPULL SWITCH
DUPLEX CONVENIENCEOUTLET
WATERPROOFCONVENIENCE OUTLET
CONVENIENCE OUTLET1 SINGLE 3 TRIPLE
RANGE OUTLET
CONVENIENCE OUTLETWITH SWITCH
SPECIAL PURPOSE(SEE SPECS.)
0 ; ...*.^X OUTLET
NiCEILING LIGHTFIXTURE
PULL CHAIN LIGHT4 FIXTURE
-s-
v ,
is,
EXTERIOR LIGHTFIXTURE
LIGHTING PANEL
POWER PANEL
MOLE-POLE SWITCH
DOUBLE-POLE SWITCH
THRINAT SWITCH
CI
FOURWAT SWITCH
SWITCH WITH PILOT LIGHT
PUSH DUTTON
Ea BELL
kIA
OUTSIDE TELEPHONECONNECTION
TILEVISION CONNECTION
S SWITCH WIRING
EXTERIOR CEILINGE3 FIXTURE
FLUORESCENT CEILINGFIXTURE
FLUORESCENT WALLFIXTURE
ELECTRICAL SYMBOLS VaTI-1 WHICH YOU SHOULD BECOME
FAMILIAR. 29 1
BEDROOM NO 1
e0CL
9
Q
PS
0CL
[ S, dbHALL .-......___,,O....
e.,
PORCH
BATH e ed.Ste. o-o DINING ROOM "0
%0 0_0 9 0, 49*to---s---
BATH
&leS
.1%..11.. qt..
//// nn/ S \ STORAGE
0 .....
\\ \
SSe/ .S.
LIVING ROOM
BEDROOM NO 2 BEDROOMNO. 3
,
S. .V
,
bGARAGE
31
EXERCISE
BEDROOM NO 1
CL CL
BEDROOM NO 2
HALL
BATH
BATH
BEDROOMNO 3
DINING ROOM
CL
CL
PORCH
KITCHEN
LIVING ROOMGARAGE
STORAGE
INDICATE THE NUMBER OF GENERAL PURPOSE, SMALL APPLIANCE, AND
INDIVIDUAL CIRCUITS NEEDED, ALSO, LOCATE ALL OUTLETS, SWITCHES,
AND OVERHEAD LIGHTS USING THE PROPER SYMBOLS.
UNIT: Basic Electricity
LESSON 3: Safety Practices to Prevent Electrical Accidents
Need:
When working with electricity, the worker must accept impor-tant responsibilities to prevent on-the-job injuries. Aproperty owner must make certain proper equipment, the equip-ment is maintained and that people in the area are safe.Responsibility for safe working practices rests with theworker.
Objectives:
1. Following this lesson, each student will be able to iden-tify those practices which are necessary to prevent on-the-job injuries.
2. Given certain accident sivations, each student will beable to identify the necessary action needed.
Interest ?Approach:
Discuss an electrical accident situation and have eachstudent or groups of students come up with what they would doif they came upon the accident.Ask how much electricity it would take to severely injure orkill a person. Write the answers down somewhere on the boardand compare to the facts later in the lesson.Have the students describe their "most shocking" experienceand tell why it happened and how it might have beenprevented.
Key questions, problemsconcerns
1. What is the key toelectrical safety?
2. What areof electricitya person?
Teaching techniques andinformation
a. Show overhead.(OH-1)
b. Think-all situations dealwith practical appli-cations and common sense.
he effects a. 60 cycle a.c. currenton passing through a person
will have the followingeffects:(OH-2)(OH-3)
1. At about onemilliamp (.001 amps)the shock may befelt.
7
33
e
3. Freeing a victimwho is in directcontact withelectricity.
4. What are some othersafety suggestions?
2. At abort ten mil li-amps (.010 amps) theshock may be severeenough to paralyzemuscles so a personcannot release theconductor.
3. At about 100 mil li-amps (0.100 amps)the shock bay befatal if it lastsfor one second ormore.
b. The amount of shockdepends on conditions atthe time and place ofcontact.
c. The wetter the environmentthe more easily shock mayoccur.
d. When shock occurs,breathing may r,top.Breathing may resumeafter a short period ofartificial respiration ifshock is not too severe.
a. The first person at theaccident should shut offthe electricity as soon aspossible If unable to dothis, the victim should beremoved from contact assoon as possible.
b. NEVER use your bare handsto pull a victim away fromelectrical contact.
c. Use a dry board, dry rope,leather belt, coat,overalls, or other non-conductors.
d. Give artifical respirationuntil a doctor or medicalaide arrives.
a. Do not tap into livewires.
b. Wear eye protection.
c. Use all tools correctly.
d. Never use extension cordsthat show wear and tear.
e. Before working aroundelectricity, remove allrings, watches or othermetal objects to preventelectrical burn.
f. Do not replace a fuse orthrow a circuit breakeruntil the cause of troublehas been found andcorrected.
g. On wiring jobs, twopersons should always worktogether.
h. Remember the ABC's ofwiring--Always Be Careful.
i. Provide a handout ofsafety practices for eachstudent.
Application and Followup:
1. Provide practical wiring accident situations and havestudents discuss how they would react under the samecircumstances.
2. Demonstrate, using correct procedures, how to free aperson who is in contact with an electrical service.
3. Demonstrate artificial respiration.
4. Have students practice with wiring safety situationsthey may face when worki.ig with electricity.
5. Have a person from the power company talk to 4-hestudents about electrical safety.
6. A home safety survey could be conducted by the students.
References
Goodheart/Wilcox, House Wiring Simplified
9
35
BE CAREFUL
THINK!STAY
ALIVE!
OH-1
ELECTRICITY PACKS A TERRIFIC WALLOP, USE YOUR
HEAD, THINK, STAY ALIVE,
Oti-2
ELECTRICAL SHOCK RESULTS WHENYOUR BODY CONNECTS
A "HOT" WIRE TO GROUND
METAL SOCKETDEFECTIVE
V(
to
WET OR,r .0DAMP FLOOR
0H-3
0 PHYSIOLOGIC EFFECTSOF ELECTRIC CURRENTS
a
0.2
Oil
0101
.001
SEVERE BURNS AND BREATHING
STOPS
DEATH
EXTREME BREATHING DIFF!CULITIES
BREATHING UPSET & LABORED
SEVERE SHOCK
MUSCULAR PARALYSIS
CANNOT LET Go
PAINFUL
MILD SENSATION
THRESHOLD OF SENSATION
38
UNIT: Basic Electricity
Lesson 4: Electricity from Plant to Farm
Need:
Electrical bills keep getting larger and larger. The cost ofelectricity is determined, to a large degree, by the mannerin which it is produced at the power plant and how it istransmitted from the plant to the farm or home. Knowing howelectricity is transmitted will help to understand the costof electricity.
Objectives:
1. Given a diagram of a plant to farm electricity plan, eachstudent will be able fill in the voltages and pathscorrectly to get amperage from an electrical power plantto the place of use.
2. Giver a typical electric meter as a measuring device, eachstudent will oe able to read and record correctly theamount of electricity used through that meter and deter-mine a total cost for the electricity used.
Interest Approach:
Ask the students how many volts are carried on thetransmission lines that come out of Colstrip on the MontanaPower Co. lines. Show pictures or diagram if possible.Allow all students to respond. Write the answers down andreview them as you get into the lesson. Show overhead.(OH-1)
Key questions, problems Teaching techniques andconcerns information
1. ..JW is electricityproduced?
2. Generally, how muchelectricity isproduced by thegeneratorsin the power plant?
10
39
a. Generators produceelectricity as they arepowered from outsidesources which include:1. Water (hydro)2. Steam (coal-fuel)3. Uranium (nuclear)4. Wind (small amounts
only)5. Sun (solar, small
amounts only)
a. Most generators producefrom 10,000 to 20,000volts- 13,500 voltgenerators are the mostpopular.
3. How does electricityget from the sourceto the point whereit is used?
4. How is the electricitythat we use in ourhomes is reduced from7,200 volts to 120 or240 volts?
5. What is an electricalmeter used for?
11
b. Only 240 volts are usedfor most electrical appli-raticns.
a. After the electricityleaves the generator step-112 Transformers increasethe voltage to 69,000volts, 345.000 volts, andup to 500,000 volts insome cases.(OH -2)
b. This increase or step-upin voltage is necessaryfor efficient transmissionof electricity over longaistances.
c. Remember from the defini-tion of voltage that volt-age is electrical pressureTo get more electricityover the line, more pres-sure is .(eeded.
J. After the elctricity hasreached its destination,transformers are used onceagain at a step-down sub-station to reduce thevoltage to about 7,200volts for distribution torural and city areas.
e. The individual electricityuser will get 7,200 voltsdelivered to the point ofuse. (ie. farm, home, etc)
a. Another transformer isused at the farm or hometo reauce the voltage to120 or 240 volts andmetered out to the oust-omer.(CH-3)
b. Most applications now re-quire electrical lines torun underground from thetransformer to the meterand distribution panel.
a. Electricity must be mea-sured in amperes to deter-mine the amount used.
40
6. !-ow do you read anelectric meter?
7. How do you determinethe amperage used?
This will give the eictriccompany a basis on whichto change for it's elect-ricity.(OH-4)
b. The unit of measure forelectrical energy is theKilowatt-Hour.
a. There are two types of
meters:(O-5)(011-6)1. Odometer type
register2. Pointer type register
b. Odometer type register-read as you would anyalulti-digit number-fromleft to right.
c. Pointer type registermeter(OH-7)1. First read the number
nearest pointer onright hand dial.
2. Read last numberpassed on second dial(counter clockwise).
3. Read last number paston third dial from theright(clockwise).
4. Read last numberpassed on fourth dialfrom the right(counterclockwise).
d. All meters have a Khvalue-number of kilowatt-hours used per disk rev-olution.(OH-R)
a. Count the number of diskrotations and multiply bythe Kh factor. Thenmultiply by the timecounted in hours. Thiswill give you kilowatt-hours of electricity used.
b. Multiply the kilowatt-hours of electricity usedtimes the company rate tofind the cost of theelectricity used.
c. Show several examples onthe chalkboard or over-head.
d. Have students do some ex-amples on the board andcalculate kilowatt-hoursand the cost.
Application and Followup:
1. Have students fill out a worksheet on electricity frompower plant to their farm or home.
2. Assign students to read their own home meters andcalculate the cost of electricity over a specified period oftime.
3. Hand out a problem sheet that deals with reading metersand figuring cost of electricity.
4. Take a short field trip and locate a substation, poletransformer, meter, etc. A slide series could be used.
References:
AAVIM, Understanding Electricity and Electrical Terms
Vocational Instructional Sedrvices: Ag. Mech. curriculummaterial. Stillwater, Oklahoma.
OH-1
DO YOU KNOW HOW TO FIGURE YOUR ELECTRICAL ENERGY BILL?
w
OH-1
-....
DO YOU KNOW HOW TO FIGURE YOUR ELECTRICAL ENERGY BILL?
44
POWERPLANT
1.4
HOW ELECTRICITY GETS TO THE FARM
12.500 volts
TRANSMISSION LINE
7 n .Sea-
FARM
~ STEP-UPSUBSTATION 132 000-
500 000 volts
7,200 voltsAusaa
srPIMoft,
SUBSTATION
RURAL_DISTRIBUTION
LIN E
45
CITY
mr.amorill=
L HOT
7200 VOLTS
r NEUTRAL
120-240 V. SERVICE
II
2
TOGROUND
4 i
WATT HOURMETER
TOGROUND
DISTRIBUTIONPANEL -*
FUSES
120 V. t240 V
120 V
48
e
THE UNIT OF MEASURE FOR ELECTRICALENERGY IS THE KILOWATT-HOUR
49
ELECTRICAL ENERGY ISMEASURED IN
KILOWATT-HOURS
50
METERS
ODOMETERTYPE REGISTER
51
0H-5 & 6
POINTERTYPE REGISTER
1
OH-7
READ THE METER
(a READ NUMBER NEAREST POINTER ON RIGHT HANDDIAL AND RECORD- 5
(b READ LAST NUMBER PASSED ON SECOND DIALAND RECORD ON LEFT OF FIRST NUMBER- 45
(c READ LAST NUMBER PASSED ONTHIRD DIAL AND RECORD- 245
(d READ LAST NUMBERPASSED ON FOURTHDIAL AND RECORD-
1 9,.
a s3 74 5 k
9'.,° 1
II , N7 ".. 3
6 5 4....__ a
I 04.II .
09 1
8 I 27 it 36 .
READ FROM RIGHT TO LEFT
PROPER METHOD OF READING POINTER-TYPE REGISTER,
START WITH RIGHT HAND DIAL AND FOLLOW STEPS AS
SHOWN,
THE Kh VALUE ON METERS IS THE NUMBEROF KILOWATT-HOURS USEDPER DISK REVOLUTION
53
METAL DISK1/
/"..-/I.,\
54
UNIT: Basic Electricity
Lesson 5: Electrical tools, Material, and Controls
Need:
Any task is easier to perform if the worker knows how, whenand where to use the appropriate tools and materials. workis more enjoyable if a person knows how to use the tool andequipment properly.
Objectives:
1. Upon completion of this lessen, each student will be ableto identify by sight all of the tools necessary for simpleelectrical work which include: pliers screwdrivers, dril-ling equipment, sawing and cutting tools, solderingequipment, wire strippers, measuring tools*, fish wire, andother miscellaneous tools.
2. Given the individual devices necessary fcr wiring, eachstudent will be able to identify it by sight and use thenames correctly in placing an order for electrical sup-plies. These will include conductors, boxes and covers,switches, receptacles, fuses, and the common types ofelectrical wire.
3. Given a common farm situation, the students will be ableto identify the different types of electrical controldevices that could be used to make the operation moreefficient and convenient.
Interest Approach:
Lay out a few electrical tools, receptacles, switches, orboxes and have students discuss what they are or what theydo. Have examples of all items handy so students can examplethem as they are discussed during the lesson.
Key .luestions, problems Teaching techniques andconcerns information
1. What tools andequipment are 'isedfor electrical work?
14
a. Show all overheads whichdeal with tools.
b. Hz.-id out the tools andallow students Lo examinethem.
c. Pliers1. Slip joint2. Linemakers3. Side cutters
5b
15
4. Diagonals5. Long nose6. Curved jaw
d. Screwdrivers(insulatedhandle)1. Conventional straight
shank2. Phillips3. Stub nose
e. Drills1. Power drill2. Ratchet brace3. Auger bit4. Expansion bit5. Twist drill6. Masonry bit
f. Cutting tools1. Crosscut saw2. Keyhole saw3. Hack saw4. Power saw
g Soldering equipment1. Paste2. Solder3. Soldering gun4. Electric iron5. Propane torch
h. Strippers1. Wire strippers2. Cable strippers
i. Measuring tools1. Extension rule2. Push-pull tape rule3. Steel tape
i Fish wire1. Steel fish tape2. Polyethylene fish tape3. Wire pulling lubricant
k. Other tools:1. Pipe cutter2. Test light3. Pipe reames4. Wood chisel5. Conduct bender
2. What conductorsare used forelectricity?
3. How are electricalwires identified?
4. What types of junctionboxes are used inelectrical wiring work?
5. Identifying the coversused in wiring.
6. What types of switchesare used in electricalwiring?
16
5'i
a. Most conductors are copperor alluminum wire.
b. Current-carrying capa-cities of conductors arerelative to wire size.(Show overhead and handout current-carryingcapacity chart.)
a. Wires are identified bysize and use.
b. Handout wire and cable in-sulation chart.
c. All wires must meet Na-tional Electric Code.
d. Show overhead of varioustypes of wires.1. Single wire conductors2. Two wire condlictors3. Cords
a. Show overhead cn box typesas well as some actualjunction boxes.
b. Boxes include1. Square junction2. Octagon junction or
ceiling outlet3. Switch or outlet4. Surface mount-used
with conduit-(showoverhead on conduit)
a. Show overhead on covers,Discuss what each is for.
a. Show overheads on switches
b. Discuss how switches work.
c. Types:1. Single pole-designed
to turn on or off onelight or appliancefrom a single locationa. Snap single poleb. Quiet type-uses
uses mercuryc. Delayed action-
after switch is
7. What are outlet recept-acles and how are theyused?
17
turned off,thelight will remainon for 30 to 60seconds.
d. touch switch-pushbutton type forhouse wiring
e. Canopy switches-used on portablecords
f. Feedthroughswitch-alsoused on cords
2. Three-way switches-3-wire switches are usedto control lights from2 different locations.Two 3-way switches arerequired.
3. Four-way switches-usedwhen light controlfrom 3 or more placesis required.
4. Dimmer switch-used toswitch a light fromfrom bright(100%) todim(approx. 25%).Install as a regularswitch.
5. Interchangable devices-these permit flex-ibility in an elect-rical installation.They include:a. Outletsb. Switchesc. Pilot lights
a. Show overheads on recept-acles.
b. Receptacles are used toplug in portable devices.Ex: (amps, toasters,radios, stoves, etc...)
c. Types:1. Duplex outlet used
for general purpose2. Single receptacle(240
volts)-used for small
58
8. What are some othercontrol devices?
18
air conditioners andother similar devices.
3. 240 volt 3-wire recep-tacle-used for dryers,ranges, welders orother heavy amperageequipment.
4. 240 volt single recep-tacle-used for largerair conditioners,heavy power tools,garden equipment, etc.
5. No-shock safety duplexoutlets-self closingoutlet which preventschildren frominserting metal intothe slots.
6. Weatherproof recept-acles used foroutdoor devices-thesehave water-tightcovers.
7. Specialty receptacles-used for T.V. jacks,telephones, etc.
a. Fuses and breakers-theseact as safety valves fora wiring system whichprotect the wiring fromoverloads and shortcircuits.
b. Circuit breakers-These arein the service entrancepanel and are rated byamperes. They will carrytheir rated loadscontinuously, and overloadfor short periosls of timeas required to start shopmotors, clothes dryers,etc.
c. Fuses-some protect fromoverload while othersprotect from short circuitonly.1. Types:
a. Plug type fuseb. Cartridge type fusec. Fustat-time delayd. Circuit breaker fuse
53
9. What is a Ground FaultInterrupter(GFI)?
d. Have the students look upthe advantages anddisadvantages of thedifferent types of fuses.
a. Fuses 8 circuit breakersand protects equipment andwiring from largecurrents.
b. The GFI is designed toprotect people from strayor short circuitcurrents.
c. If the current in the"hot"wire and the currentin the neutral wire arenot equal.
d. If the two currents arenot equal, a fault existsand some current isleaking.
e. If this happens the GFIwill open the circuit.
Application and Followup:
1. Lay out all devices and tools for inspection and use.
2. Using a wiring diagram, identify where some of thematerial wil be used.
3. Have small sections of wire available and demonstratehow to use some of the tools to cut, bend, and connectwire as well as how to insert wire into devices.
4. Have a contest to determine where the most types ofelectrical switches, sensing devices and receptacles arefound in the classroom and shop area.
References:
Goodheart/Wilcox, House Wiring Simplified
AAVIM, Electrical Wiring, student workbook
19
6o
OH-1A
ELECTRICAL TOOLS
kLAT BLADE SCREWDRIVER
ADJUSTABLE JAW WRENCH
PHILLIPS SCREWDRIVER
CROBERTSON SCREWDRIVER
uheMAN'S PLIERS
LOCKING PLIERS
CABLE CUTTERS
'. ',I. PLIERS
CHANNEL-LOCK PLIERS
WIRE STRI' ^ER
PIPE WRENCH
1(
PORTABLE ELECTRIC DRILL
HOLESAW BITE ME=1STAR MASONRY DRILL
WOOD BIT
SONE--Pesirm,.-
m011111111Aavt_ *ifFOLDING RULE'
RETRACTABLE TAPE MEASURE
LEVEL
110 aDI ==I 45C-TZFC11
61PLUMB0111
OH -1B
ELECTRICAL TOOLS
HAPiD SAW
C
COMPASS OR KEYHOLE SAW
t'r
PORTABLE ELECTRIC SABERSAW
=>=c01====1WOOD CHISELS
HACKSAW`4e ' 7
ELECTRIC SOLDERING IRON:
011111=i1=1110
PUSH DRILL CONDUIT BENDER1,
Alli"4111411111,ELECTRICIANSTOOL POUCH
62
VOLT-OHMMETER ^
011-2
ELECTRICAL CONDUCTORS
0 , 2 4 6
AMERICANWIRE
8 10 12 14 GAUGE
COPPER CONDUCTORS BY GAUGE HUMBER. THE WIRE GETS
SMALLER AS THE GAUGE NUMBERS GET LARGER.
1
HANDOUT # 1
SIZE CURRENT-CARRYING CAPACITY (Amperes)
Rubber-Insulated Rubber- Weather-
Weight Wire In Insulated Proof ResistanceDiameter (Feet Per Conduit Or Wire On Wire On (Ohms Per
Number (Inches) Pound) Cable Insulators Insulators 1,000 Feet)
241816
.0201
.0403
.0508
817.6203.4127.9
14 .0640 80.44 15 24 30 2.4812 .0808 50.59 20 31 39 1.5610 .1018 31.82 25 42 54 0.988 .1284 20.01 35 58 71 0.626 .184 12.58 50 78 98 0.394 .232 7.91 70 105 130 0.242 .292 4.97 90 142 176 0.151 .332 3.94 100 164 203 0.12
1/0 373 3.13 125 193 237 0.102/0 .419 2.48 150 223 274 0.083/0 .470 1.97 175 259 118 0.064/0 .528 1.56 225 298 ,168 0.05
COPPER CONDUCTORS: DIAMETER, WEIGHT, CURRENT-
CARRYING CAPACITY IN AMPERES, RESISTANCE IN
OHMS PER 1,000 FEET.
64I
HANDOUT e 2
LETTERINSULATION TYPE
WEATHERPROOF WP
SLOW-BURNING SB
SLOW-BURNING WEATHERPROOF SBW
RUBBER:Code Compound RHeatRai:tent RH
RH HMoisture-Resistant RWMoisture and Heat-Resistant RHRW
RHWLatex (Regular) RULatex (Moisture-Resistant) RUWLatex (Heat-Resistant) RUH
MINERAL (METAL-SHEATHED) MITHERMOPLASTIC COMPOUNDS:Thermoplastic TMoistureResistant Thermoplastic TWMoisture tend Heat-Resistant Thermoplastic THWThermoplastic and Fibrous Outer Braid TBSThermoplastic and Asbestos TA
VARNISHED CAMBRIC:Standard BlackHeat-Resisting V
PAPER:Solid TypeOil-filledOilostaticUntreatedTreated
ASBESTOS:Nonimpregnated A and AAImpregnated Al and AIAAsbestos-Varnished-Cambric Outer Asbestos Braid . . . AVALead Covered AVLCotton Braid Covered AVB
SILICONE ASBESTOS SA
TYPES OF WIRE AND CABLE INSULATION: NATIONAL
ELECTRIC CODE DESIGNATIONS.
011-3
SPECIAL PURPOSE CORDS
THERMOSTAT
TV LEAD IN
TV LEAD IN
COAXIAL CABLE
STRANDED SPEAKER
#
VACUUM CLEANER CORD
OH -4A
SINGLE WIRE CONDUCTORS
INSULATION
c.......COPPER WIRE
8
421222112inggiste=sgeff II 10
111:17-- 12
"...MOMS 14
e OH-4B
SHEATHED CABLE
PAPER WIRE
TWO WIRE NONMETALLIC SHEATHED CABLE WITHOUT GROUND
TWO WIRE SHEATHED CABLE WITH GROUND WIRE
i
OH-4C
ARMORED CABLE
METAL ARMOR BARE GROUND INSULATION
METALLIC ARMORED CABLE. THREE-WIRE
CABLE WITH BARE GROUND
METALLIC ARMORED CABLE. TWO-WIRE
CABLE WITH GARE GROUND
JUNCTIONS BOXES
SQUARE JUNCTION BOX
OCTAGON SHAPED JUNCTION
OR CEILING OUTLET BOX
OH-5A
OUTLET BOX EXTENSION
OH-5B
OUTLET BOXES
OUTLET BOX WITH
SQUARE CORNERS
OUTLET EOX WITH
BEVELED CORNERS
AND CLAMPS
SHALLOW CEILING BOX SURFACE MOUNTED BOX
OH-6
PLATES & COVERS
SINGLE, DUPLEX AND GANG TYPE BOX PLATES
AND COVERS
OH-7A
CONDUIT & FITTINGS
0
THINWALL CONDUIT
THINWALL CONDUIT FITTINGS
OH-7B
CONDUIT
FLEXIBLE STEEL CONDUIT WITHOUT WIRES,
FREQUENTLY CALLED "GREENFIELD,"
Ca
ALUMINUM RIGID CONDUIT
74
)
BOXES & COVERS
000
0o
0
0
0
10
OH-8
0
0
6OH-9
SINGLE POLE SWITCH
THE SINGLE-POLE SWITHCH WITH THE TWO TERMINALS, IS
USED TO TURN ON AND OFF, ONE LIGHT OR APPLIANCE
FROM A SINGLE LOCATION. NOTE HOW A TYPICAL SINGLE-
POLE SWITCH WORKS.
OH-10
QUIET SWITCH
SINGLE POLE SWITCH OF QUIET TYPE. NOTE HOW THEY
WORK,
MERCURY OPERATED, DELAYED ACTION AND TOUCH SWITCH.
77
CANOPY SWITCA
TUMBLER
PUSH BUTTON
OH-ll
PULL CHAIN
FEED THROUGH SWITCH
OH-12
3 -WAY SWITCH
THREE-WAY SWITCH, NOTE THE THREE
TERMINALS.
IN A THREE-WAY SWITCH, THE CIRCUIT IS
COMPLETED BY MOVING BOTH SWITCHES
EITHER UP OR DOWN.
79
4-WAY SWITCH
FOUR-WAY SWITCH. NOTE THE
FOUR TERMINALS.
OH-13
A FOUR-WAY SWITCH IS A SPECIAL DOUBLE-POLE,
DOUBLE-THROW SWITCH, USED BETWEEN TWO THREE-
WAY SWITCHES TO PROVIDE AN ADDITIONAL SWITCH
FROM WHICH A LIGHT MAY BE OPERATED.
so
OH-14
DIMMER SWITCH
A DIMMER SWITCH OF THE TYPE SHOWN SHOULD NOT
BE USED TO CONTROL WALL OUTLETS, FLUORESCENT
LIGHTS, .PPLIANCES OR MOTOR-DRIVEN
EQUIPMENT.
81
Oh-15
INTERCHANGEABLE DEVICES
GREEN HEX SCREW
OUTLET
BREAKOFF FIN
OH-16
DUPLEX OUTLET. NOTE GREEN HEX SCREW
TERMINAL FOR GROUNDING WIRE, ALSO
BREAKOFF FIN.
OH-17
RECEPTACLES
RECEPTICLE (240V) FOR TANDEM BLADES
AND U-SHAPED GROUND,
RECEPTICLE FOR THREE WIRES (240V),
84
fo
1
OH-18
RECEPTACLES
GREEN
RECEPTACLE (240V) FOR HORIZONTAL AND
VERTICAL BLADES AND U-SHAPED GROUND.
NO-SHOCK OUTLET WITH SELF-CLOSING
OPENINGS.
85
*WEATHERPROOF
RECEPTACLES
OH-20
SPECIAL RECEPTACLES
WALL PLATE FOR
A TELEPHONE
WALL PLATE FOR
A TV
1. COMMON FUSES
A. PLUG
B. CARTRIDGE
C. BLADE
2. FUSETRONS
A. PLUG
B. CARTRIDGE
C. BLADE
3. FUSTATS
OH-22
CIRCUIT BREAKER
LINETERMINAL FIXED
MAINCONTACT
MOVABLEMAIN CONTACT
LINETERMINAL
BIMETALUCSTRIP
A CIRCUIT BREAKER IS A SWITCH
IN THE BLACK OR "HOT" WIRE THAT
OPENS AUTOMATICALLY WHEN A
PREDETERMINED CURRENT OVERLOAD
FLOWS THROUGH IT.
0
,',,,,. A_;4,,
A,
WirtTLll.1'
Tho
-"\
el
100 AMP. MAIN BREAKER(SHUTS OFF POWER) '
30 AMP. CIRCUIT (24011) FORDRYER, HOT WATER HEATER,----"yAIR CONDITIONING, ETC.
FOUR 20 AMP. CIRCUITSFOR KITCHEN AND SMALL -..--a.APPLIANCES, POWER TOOLS
IM
a) 1
na
I
40 AMP. CIRCUIT (120 TO 240V)FOR RANGE
FOUR 115 AMP. CIRCUITS FOR'10----GENERAL PURPOSE LIGHTING,
TELEVISION, ETC.
SFACE FOR FOUR 120V0-..-...- CIRCUITS TO BE ADDED
FO I". FUTURE LOADS
BREAKER ARRANGEMENT FOR 100 AMP, ENTRANCE PANEL,
9192
FUSES
PLUG TYPE FUSE, THE GLASS TOP HELPS
PREVENT SHOCKS WHEN CHANGING FUSES.
OH-25
PLUG TYPES FUSES, CURRENT PASSES THROUGH STRIP
OF THIN METAL. RIGHT FUSE IS BLOWN.
CARTRIDGE TYPE FUSES,
93
0E1-'2.6
FUSE & BREAKER
ADAPTER
FUSTAT AND ADAPTER
FUSE LINK
SPRING
HOW FUSTAT IS CONSTRUCTED
SMALL CIRCUIT BREAKER THAT SCREWS
INTO A FUSE SOCKET.
OPERATING,..PRINCIPLE OF ADELAYED ACTION
FUSE
CONTINUEDOVERLOAD
95
NORMAL
SHORT CIRCUIT
9b
TYPES OF FUSES
417
DELAYED ACTIONFUSE
UNIT: Basic Electricity
Lesson 6: Types of Electrica' Circuits
Need:
A knowledge of electrical circuits is needed to plan a safe,efficient and economical wiring system. Such knowledge isimportant when selecting wire types and sizes, fuse types andsizes and determining the location of appliances, outlets,and receptacles.
Objectives:
1. Given a drawing ,- actual circuits, each student will beable to identify a complete circuit and whether it isparallel or series.
2. Given a set of circuits, each student will be able toidentify them as general purpose, split-circuit,appliance circuit, individual circuit, or 240 voltspecial purpose circuit.
Interest Approach:
Using a light board, have the students set up a parallel andseries circuits. Have students unscrew a light bulb from thecircuits and then start a class discussion as to why the restof the lights in the parallel circuit are on and all thelights in the series circuits are off.
Key questions, problems Teaching techniques andconcerns information
1. What is an electricalcircuit?
2. What is a completeelectrical circuit?
3. What are the two basickinds of electricalcircuits?
a. A circuit is the pathfollowed by electrons fromone point to another.
a. A complete circuit is madeup of both a del ivery wireand a retu :n wire.(OH-1)
b. This is necessary to takeelectricity from thesource to a point of useand back again.
a. Series1. Series circuits provide
for all the electricityin the circuit to flow
e
4. Most parallel circuitsare of two types.
through each point ofuse (lamp, appliance).(OH-2)
2. If the current isstopped at one placethe entire circuit isbroken.
3. Using wiring boards,have each studentconstruct a seriescircuit.
4. Have the students,through supervisedstudy, determine thea d v a n t a g e s a n ddisadvantages of aseries circuit.
b. Parallel1. Parallel circuitsprovide for dividingthe current f lowthrough each lamp orappliance in thecircuit.(OH-3)
2. If the current flow isinterrupted at any oneplace, the rest of thecircuit continues toflow with electricity.
3. Most wiringapplications useparallel circuits.
4. Using wiring boards,have each studentconstruct a parallelcircuit.
5. Have the students,through supervisedstudy, determine thea d v a n t a g e s a n ddisadvantages of aparallel circuit.
a. Branch circuits-is thecircuit between the lastfuse or breaker and theoutlets.(OH-4)
b. The three common branchcircuits are:1. Appliance circuits
-minimum of two 20 amp
5. What is a short circuit?
circuits in kitchen anddining area.(OH-5)
2. General purposecircuits-minimum of one20 amp, 120 voltcircuit for each 500sq. ft.- each 20 amp circuitwith #12 wire will havea 2100 watt capacity.- minimum of 12 ft.between convenienceoutlets.(OH-6)
3. Individual equipmentcircuits-wired directlyrow m the entrance panelto only one applianceor item of electricalequipment. (OH -7) (OH -8)- It is installed forequipment that requirelarger amounts ofelectricity.- For some applications,larger gage wire andlarger ampacity circuitbreakers or fuses arerequired.-Some equipment must bewired for 24 volts or acombination of 120/240volts.- All motors 1/2 hp. orover-Welders- Livestock wateringdevices-Water heaters
c. Feeder circuits-This is acircuit between the SEPand fuse or circuitbreaker protecting branchcircuits.(OH-9)
a. When the delivery wire ina circuit crosses a returnwire directly a shortcircuit occurs.
b. Short circuit protectionprovided by fuses orbreakers. (OH-10) (OH-ll
Application and Followup:
1. Have each student build a series and a parallel circuitusing light sockets.
2. Using a house wiring diagram, have the studentsidentify the circuits by type and purpose.
References:
AAVIM, Electrical WiringAAVIM, Understanding Electricity and Electrical TermsGoodheart/Wilcox, House WiringEdison Electric Institute, Agricultural Wiring Handbook
23
102
0
01-i-1
A SIMPLE ELECTRICAL
CIRCUIT
A SIMPLE SERIES CIRCUIT
LAMPDELIVERY FILAMENTS ...
WIRE
" / A
GENERATOR
RETURNWIRE
104
A CIRCUIT STARTS AND RETURNS TO A FUSE BOX, IT USUALLY SUPPLIES POWER T
SEVERAL POWER_USE OUTLETS.
FROMGENERATOR
tSWITCH
SWITCH
RETURN TOGENERATOR
105
BRANCH CIRCUIT
LIGHT OUTLET
BRANCHCIRCUIT
CIRCUITBREAKERS
RECEPTACLE OUTLET
OH-L4
A BRANCH CIRCUIT STARTS AT THE FUSE OR
CIRCUIT BREAKER IN THE SEP AND RUNS TO
ONE OR MORE OUTLETS.
Summary of Residential Outlet Locations
This table is given for quick reference and is necessarilycondensed. For complete detailed information, refer tothe Residential Wiring Design Guide.
SPACE
Living room,Farm office
Dining areas
Kitchen
Family room
Laundry
Bedrooms
BathroomsLavatories
Recreationroom
Hall
Stairways
Uri
LIGHTINGOUTLETS
General Illumination;wall-switch controlled.
1 outlet, wall-switch controlled.1 ceiling outlet; wall-switchcontrolled.
General illumination plus light oversink, wall-switch controlled.Work-area lighting.
Same as 1.viMI 700M.
General illumination;wall-switch controlled.Work-area lighting
General illumination,wall-switch controlled.
Ccod illumination of face at mirroressential, wall-switch controlled.
General illumination,wall-switch controlled.
General Illumination;wall switch controlled 3-way ifhall is 10 ft. or longer.
Outlets for adequate illumination ofeach stair flight. Multivle control athead and foot of stairs, ay.
TYPE OF CONVENIENCE TYPE OFCIRCUIT OUTLETS CIRCUIT
Cen. No point at v 1.1: line more than 6 ft.from an outle' outlet in mantel shelf.2 or more outlets switch controlled.Outlet in any wall space 2 ft. wideor greater.
Cen. No point at wall line more than 6 ft.from an outlet. Outlet in any wallspace 2 R. wide or greater.
Cen. 1 for every 4 ft. of kitchen work-surfacefrontage.I at refrigerator location.2 at table location.2 or more 20-amp circuits to serve theseoutlets.
Cen.
Cen.
120/240 V split-circuit for each outlet.
1 outlet, for general use.
SPECIAL-PURPOSEOUTLETS
Cen. 1 for air conditioner.
App. 1 for air conditioner
/pp.
App.
App.
Cen. No point at v 211 line more than 6 ft. Cen.from an outlet. Outlet on each side,and within 6 ft. of center line of eachbed location. Outlet in any wall space2 R. wide or greater.
Cen. 1 near mirror. Cen.
Cen. No point at wall line more than 6 ft. App.from an outlet, outlet in mantel shelf.Outlet in any wall space ", ft. wideor greater.
Cen. 1 for each 15 ft. of hallway. Cen.Halls over 25 sq. ft. at least one outlet.
Cen. 1 at intermediate landings. Cen.
1 for range.1 for clock and home freezer.1 for fan.I for dishwasher-waste disposal unit
(if plumbing facilities are installed)
1 for washer.1 for hand iron or ironer.I for clothes dryer.I for water heater.
1 for room air conditioner.
1 for built-in space heater.1 for built-in fan,wall-switch controlled.
1 for air conditioner
TYPE OFCIRCUIT
Ind
Ind
Ind.Ind.Cen.Ind
IndAppInd.Ind.
Ind
Ind.
Cen
Ind
tSummary of Residential Outlet Locations
SPACE
Closets
Exteriorentrances
Porches
Yard lights
Terraces andpatios
Basement andutility space
Carden andChristmaslighting.garden tools
Accessible attics
Garage
LIGHTINGOUTLETS
1 outlet.
1 or more outlets;wall-switch controlled.
1 outlet for area of more ti-an75 sq. ft., wall-switch controlled.If enclosed, treat as a living roomspace.
1 or more host lights controlled bytime-delay switch orphotoelecta: cell.
General illumination;wall-switch controlled.
General illumination of workareas. equipment and stairwAys.
1 outlet, wall-switch controlled.1 for each enclosed space.
1 per car near hood and one nearback for trunk, wall-switchcontrolled. I for exterior lighting,multiple-switch controlled ifgarage is detached from house
TYPE OFCIRCUIT
Cen.
Cen.
Cen.
Cen.
Cen.
Cen.
Gen.
Cen.
CONVENIENCEOUTLETS
None.
TYPE OFCIRCUIT
I or more preferably near each entrance, Cen.weat herproof (WP), 18 in. above grade.
1 for each 15 ft. of wall bordering Cen.porch. If enclosed porch treat as livingroom.
1 WP, at least 18 in. above grade for Cen.each 15 R. of wall bordering terraceor patio.
2 outlets or more, depending on useand size of space.
SPECIAL-PURPOSEOUTLETS
Cen. 1 for electrical equipment in con-nection with furnace.1 for freezer (and kitchen clock).
Provide WP outlets at locations con- Cen.venient for connection of lawn mowers,hedge trimmers and Christmas orgarden lighting.
1 for general use.
1 on each wall
TYPE OFCIRCUIT
Ind.
Cen. 1 for cooling fan, with switch control. Ind.
Cen. If food freezer, work bench orautomatic door opener is planned,provide appropriate outlets.
Ind
109
Notes on Preceding Table
Gen.Outlets supplied by General-Purpose Circuits.App.Outlets supplied by Appliance Circuits.Ind.Outlets supplied by Individual-Equipment Cir-
cuits.A convenience outlet to be at least of the duplex
grounding type (two or more plug-in positions), exceptas otherwise specified.
All spaces for which wall-switch controls are required,and with more than one entrance, to be equipped withmultiple-switch control at each principal entrance. Ifthis requirement would result in the placing of switchescontrolling the same light within 10 ft. of each other,one of the switch locations may be eliminated.
11
SERVICEENTRANCE
\PANEL
SMALL APPLIANCECIRCUIT
WIRE TRAVELSTHROUGH STUDS
APPLIANCE CIRCUIT
L 01
0
A SMALL APPLIANCE CIRCUIT BEGINS AT THE SEP AND RUNS THROUGH STUDS TO
THE KITCHEN RECEPTACLES,
111
011 -6
GENERAL PURPOSE CIRCUITS
. r
GENERAL PURPOSE CIRCUITS SUCH AS CEILING LIGHTS
AND RECEPTACLES IN A BEDROOM MAKE UP THE LARGEST
PART OF THE WIRING SYSTEM FOR A HOME.
112
1
OH-7
INDIVIDUAL CIRCUIT
SEPARATE CIRCUIT
SERVICEENTRANCE PANEL
WATER HEATER
AN INDIVIDUAL CIRCUIT HAS SEPARATE WIRING FROM
THE SERVICE ENTRANCE PANEL TO THE OUTLET FOR
ONLY ONE APPLIANCE OR ITEM OF ELECTRICAL EQUIP-
MENT, SUCH AS THE WATER HEATER,
113
OH-8
RANGE OR DRYER HOOKUP
3-PRONG PLUG BLACK WHITERED
NRANGE ORDRYERTERMINAL
114
3-WIRE"PIG TAIL"
FEEDER CIRCUIT
SERVICE ENTRANCE SMALLER CIRCUITPANEL BREAKER PANEL
/FEEDER CIRCUIT BRANCH CIRCUIT
A FEEDER CIRCUIT EXTENDS BETWEEN TEE SEP AND A FUSE OR CIRCUITBREAKER PROTECTING A BRANCH CIRCUIT,
115
RESIDENTIAL POWER DISTRIBUTION SYSTEM
POOL OUTLETS
BASEMENT LIGHTING AND OUTLETS
FIRST FLOOR LIGHTING
UVING/FAMLY ROOMs.0.-.. Ems NM
TIMOOM LIGAND OUTLETS
HTING
flaw Ow Ole00141,01 UM
[BEDROOM OUTLETSUlm. Rub
KITCHEN 1,PPLIANCESItelpm irt ISM
KITCHEN APPLIANCES,ftwift.sim
KITCHEN OUTLETSItrawlase WOW
GFCI
SERVICE CABLETO HOUSE
CONDUITTO METER
200 AMP. MAINCIRCUIT BREAKER
20A
15A /*
15A
15A
GFCI I5A
15A
20A
20A
KITCHEN LIGHTING A
.-
11.
GFCI
METER
CIRCUIT BREAKERAND DISTRIBUTIONPANEL
*PO
20A
20A
20A
20A
GARAGE OUTLETSMs Pork *Mar W.
FURNACENNW
MN.. W. MN
GFCI
SHOP EQUIPMENT(MUM t IMOOm NOW
UTILITY ROOMnow
50A
20A
A
50A
wUTILITY ROOM
OVEN - RANGEsmi.mom
DISHWASHER
I
SINK DISPOSAL UNIT
WATER HEATER
I CENTRAL AIRCONDITIONER
MINIM
CIRCUITS IN THE COMPLETED RESIDENTIAL WIRING SYSTEM ARE SIZED TO MEET
THE REQUIREMENTS OF FAMILY LIVING AND LEISURE.
116
CIRCUIT OVERLOAD PROTECTORS
CIRCUIT BREAKER
FUSE BOX
OVERLOAD
(a)
METAL STRIP
BoassPI
V1=,
SHORTCIRCUIT
118
UNIT; Basic Electricity
Lesson 7: Practical Wiring Applications
Need:
The ability to complete single electrical wiring projectscan save the producer or business owner time and moneyprovided they can perform their skills according to thestandard electric code. Many of the electrical wiringapplications are quite easy if one follows the correctprocedure.
Objectives:
1. Given all necessary wiring materials and tools, eachstudent will be able to correctly wire, on a board, SPSTswitch to light, multiple outlets, 3-way switches, and4-way switches, using the correct connections, wire, andtechniques.
2. Given wiring diagrams, each student will be able tocomplete all the connections necessary to make thecircuits complete using colored pencils to identify thedifferent colors of wires.
3. Given wire, solder and the correct tools and devices,each student will be able to make electrical splicesusing solderless connectors and soldering guns or irons.
4. Given damaged cord ends, each student will be able tocompletely repair that end by replacing either a male orfemale plug end.
Interest Approach:
Have students assemble the boards that the students will useduring their wiring exercises.
Key questions, problems Teaching techniques andconcerns information
1. Wiring an SEP
2. Making connections
a. Overhead 1b. Overhead 2c. Overhead 3
a. Splicing (OH-4)b. Soldering and Taping (OH -5)c. Solderless Connectors(OH-6)d. Connecting Wires (OH-7)
24
119
3. Wiring ground typeconvenience outlets.(use which ever youwish)
e.
a.b.c.
d.e.f.
g.h.
i.
j.
Give a demonstration onhow to construct each ofthe common electricalconnections.
Single circuit outlets OH8OH 9OH 10OH 11OH 12OH 13OH 14Split circuit outlets OH15OH 16Duplex outlet with switch
k.OH 17Split circuit with switchOH 18
4. Types of switches a.b.c.
SPSTThree-way OH 19Four-way OH 19
5. Wiring SPST switches a.b.c.d.e.
OH 20OH 21OH 22OH 23CH 24
6. Wiring 3-way switches a.b.c.d.
OH 25OH 26OH 27OH 28
7. Wiring 4-way switches a.b.
OH 29OH 30
8. Special wiring applications a.b.c.d.
OH 31OH 32OH 33OH 34
9. Replacing a standard a. OH 35plug b. OH 36
10. How are the methods,procedues, and codes
a. The National FireProtection Assoc. under
determined? the auspices of theAmerican NationalStandards Institute
25
120
(ANSI), sponsors theNational Electric Codewhich provides minimum
standards for the safeelectrical wiringinstallations.
b. When in d'_lbt about anywiring application, referto the National ElectricCode.
c. All wiring is to becompleted under permitonly.
Apnlication and Followup:
1. Use the "wiring layout" handout and have studentscomplete a written diagram. Make up several otherdiagrams from overheads and have students fill them out.
2. Make up a wiring voard for each student or each pair andlet sudents practice wiring outlets, switches and wiresplicing and connecting.
3. Have students repair electrical applianLc 'ords.
4. Make a mock structure and have students wire anSEP panel, switches, and outlets, and range plug.
5. Take a field trip and observe wiring being completed.Observe ac wiring especially.
SERVICE ENTRANCE
SERVICEENTRANCE WIRES
CABINET
.111111 Ilk 0G)000e024L
Pri_l
0Gr.000e0°
111
IN1,1 1
rail'E:',:
rm..A
I I
r:. nil I 1! !! m
a
a.0
0
13 a
1.3of0
a
11 .
122
NEUTRAL BARAND TERMINAL
IRCUIT BREAKERS
PANEL FORADDITIONALCIRCUIT BREAKERS
GROUNDED BAR,
SERVICE ENTRANCENEUTRAL WIRE
COPPERGROUNDING WIRES
WHITENEUTRAL WIRES
GROUNDEDNEUTRAL BAR
GROUNDINGWIRE
OH-2
ALL WHITE NEUTRAL WIRES MUST BE CONNECTED
TO GROUNDED NEUTRAL BAR IN THE SEP FOR
EACH CIRCUIT.
123
1'
GROUNDING APPLIANCES
All
I.II
10$9
e
e
®0 NEUTRALe®0
BAR
SYSTEMGROUNDINGWIRE
a)'
OUTSIDEGROUNDINGEL CTRODE
1SYSTEMGROUNDINGWIRE FROMNEUTRAL BAR
44/111METALWATER PIPE
APPLIANCEFRAME
GREENGROUNDINGWIRE
TERMINALCONNECTIONS
HE GROUNDING WIRE CONdECTS TO THE METAL FRAME OF THE WASHER, TO THE RECEPTACLE
BOX AND TO THE NEUTRAL BAR IN THE SERVICE ENTRANCE PANEL.
124
OH-4
SPLICING-
WESTERN UNION SPLICE
CENTER TAP SPLICE
RAT TAIL SPLICE
Q11-5
SOLDERING & TAPING
,sitilk APPLYING SOLDER
SO SOLDER WILL FLOW EASIER, FIRST COAT WIRES WITH ELECTRICSOLDERING PASTE. WITH SOLDERING IRON, HEAT WIRES UNTILSOLDER MELTS AND FLOWS INTO EVERY CREVICE.
APPLYING44#PLASTICTAPE
PLASTIC TAPE DOES A FASTER, NEATER,CLEANER JOB THAN RUBBER AND FRICTIONTAPE. EASIER TO HANDLE, TAKES LESSSPACE IN BOXES. DOES THE WORK OF BOTHRUBBER AND FRICTION TAPE. WATER-PROOFACID-PROOF.
DK-6
SOLDERLESS CONNECTORS
TYPE B M1'
i
Jr
On runs to buildings and to power feed lines use solderlessconnectors. Type A taps an existing line with strain on wires. UseType B for electric service connections. Insulate with plastic tape.
INSTALLATION, CUT-AWAY VIEW
Solder less connectors eliminate the need for soldering joints.Some are made of insulating material so wires need not be taped. . .
short circuits can't occur. Just screw connector over wires as shown.
127
01!-7
CONNECTING WIRES
COMBINATIONWIRE CUTTER
1\\
MAKES A HANDY TOOL THATCUTS AND STRIPS CLEAN ALLSIZES OF SOLID OR STRANDEDCOPPER WIRE. USE ALSO FORLOOPING WIRES UNDER SCREWS.
CUTTING WIRE WITH
c=41111111111111111WRONG WAY RIGHT_ WAY
REMOVE INSULATION BY CUTTING AT A SLANT.... AS IN SHARPENING APENCIL EXPOSE 2 INCH OF COPPER CONDUCTOR. REMOVE ALL PARTSOF INSULATION, BUT NOT TIN COATING WHICH KELPS SOLDERING.
CONNECTIONS AT SCREW TERMINALS
ammosto4 minso*WRONG WAY R1GHT_WAY
BEND END OF METAL WIRE INTO A LOOP TO FIT AROUND SCREW. BE SURETO ATTACH LOOP IN DIRECTION IN WHICH SCREW TURNS WHEN TIGHTENINGAS ILLUSTRATED ABOVE.
GROUNDING-TYPE CONVENIENCE OUTLET
J--BREAKER BOX
GROUNDING WIREFASTENED TO
APPLIANCE FRAME
GROUNDING WIRECONNECTED TO
SYSTEM GROUND
129
WATER PIPETERMINAL
CONNECTIONS 130
I I
CONNECTING WHITE WIRETO RECEPTACLES
WHITE WIRE
TERMINAL POST
(a)31
SECOND WHITE WIRE/ (IF APPLICABLE)
4=;)
HOLE
WHITE WIR
(b)
CONNECTING BLACK WIRE TO RECEPTACLE
BRASS SCREWTERMINAL :.
45 02/
OH-11
CONNECTING GROUND WIRETO RECEPTACLE
0
GROUNDINGTERMINAL POST
13$//511
OH-12
SINGLE RECEPTACLE
PLASTICOUTLET BOX
BAREGROUNDINGWIRE GROUNDING
TERMINAL
/3.036
OH -B
CONNECTING AN OUTLET
TIGHTENWIRE NUT
GREENWIRES SLIGHTLY GREEN
FOLDED
CONNECT THE TWO ENDS OF THE FOLD WIRES ACCORDION
GROUNDING WIRES.
MOUNTINCSCREW
TILTEDBOX
RECEPTACLE(STRAIGHT)
MOUNTINGSCREW
STYLE.
ADJUST RECEPTACLE LEFT OR RIGHT ATTACH COVER PLATE
OH-14
BACK VVI RED RECEPTACLE
PLASTEREARS
SCREWS FORSIDE WIRIN
STRIPGAGE
HOLES FORBACK WIRING
GREENGROUNDINGSCREW
STRIP INSULATION AS REQUIRED AND INSERT
WIRE INTO HOLES OF BACK-WIRED RECEPTACLE
138
BREAK-OFFTAB
OH-15
SERVICE ENTRANCEPANEL
REMOVE THE CONNECTOR TAB YO WIRE THE DUPLEX RECEPTACLE WITH A
CIRCUIT ON THE UPPPER AND LOWER OUTLETS
2-POLECIRCUIT.BREAKER
4
A SPLIT 240- VOLT CIRCUIT MUST HAVE A MEANS TO DISCONNECT BOTH
HOT WIRES AT THE SAME TIME SUCH AS A TWO POLE CIRCUIT BREAKER
TAB REMOVED
SPLIT RECEPTACLE WIRED WITH TWO 12-2 WITH
GROUND CABLES
TAB REMOVED
SPLIT RECErfAcLE WIRED WITH 12-3 WITH
GROUND CABLE
OH-16
1. BLACK
2. RED
3. WHITE
4. GREEN
5. BARE COPPER
OH-1" A
SWITCHED SPLIT RECEPTACLE
Oh-17 B
SWITCHED DUPLEX RECEPTACLE
TO NEXTRECEPTACLE
142
SOURCE
Single-Pole
SWITCHES
Three-Way
03
Four-Way
SWITCH LIGHTING OUTLET
SINGLE-POLESWITCH
WHEN THE WHITE WIRE IS CONNECTED ON THE INPUT SIDE OF THE SWITCH LOOP, IT IS
NOT NECESSARY TO IDENTIFY THE WHITE WIRE AS A HOT WIRE
WIRING TWO SINGLE POLE SWITCHES TO CONTROL TWO DIFFERENT LIGHT OUTLETS
SOURCE
FIXTURE NO. 1
FIXTURE NO. 2
SWITCHNO. 1
SWITCHNO. 2
1 = WHITE
2 = BLACK
3 = RED
146
SINGLE POLE SWITCH CONTROLS TWO LIGHTING OUTLETS WITH LIGHTING OUTLET
SOURCE
SOURCE
LIGHTING OUTLET.* NO.2
FIXTURE NO.1 FIXTURE NO.2
14/
SINGLE POLE SWITCH WITH TWO LAMPS AND UNSWITCHED LINE
FIXTURE NO.1 FIXTURE NO.2
1 RED
2 0 BLACK
3 'HWHITE
2-WIRE UNSWITCHED CIRCUIT
148
EXAMPLE OF THREE WAY SWITCH CIRCUIT
FROM SOURCE
SWITCH NO. 1
149
i
SOURCEA'
WIRING FOR THREE WAY SWITCH WITH LIGHTING OUTLET SOURCE
2-WIRE CABLE 3-WIRE CABLE
COMMONTERMINAL
/I
SWITCH NO. 1 SWITCH NO. 2
1
1 = BLACK 2 = RED 3 = WHITE
150
WIRING FOR THREE WAY SWITCHES WITH LIGHTING OUTLET BETWEEN SWITCHES
COMMONTERMINAL
3-WIRE CABLE
COMMONTERMINAL
SWITC'i NO. 1 SWITCH NO. 2
FROM SOURCE
1 = BLACK 2 -A FsED 3 = WHITE
151
WIRING FOR THREE WAY SWITCHES WITH LIGHT AT END OF RUN USING SWITCH SOURCE
COMMONTERMINAL
cr3-WIRE CABLE 2-WIRE CABLE
COMMONTERMINAL
SWITCH NO. 1 SWITCH NO. 2
SOURCE
152
1 = BLACK
2 = RED
3 = WHITE
0
...-....--......-........-
A CIRCUIT CJNTAINING ONE FOUR WAY
SWITCH AND TWO THREE WAY SWITCHES
ALLOWS CONTROL FROM THREE LOCATIONS
153
OH-28
SOMCE
WIRING FOR FOUR WAY SWITCH AND TWO THREE WAY SWITCHES
2-WIRE CABLE 3-WIRE CABLE
COMMON'TERMINAL
SWITCH NO. 144' SWITCH NO. 2 -A-
.-c 74
2 * RED'
3 m WHITE
COMMON..TERMINAL'
SWITCH NO. 3
154
S
LIGHT SWITCH
SWITCH CONTROLS ONLY THE RECEPTACLE
OUTLET
OH-31
COMBINATION SWITCH AND RECEPTACLE WHERE A SWITCH CONTROLS A LIGHT
BUT NOT THE RECEPTACLE
156
THE SWITCH AND OUTLET ARE ON SPLIT
WIRED CIRCUITS
157
DOUBLE POLE SWITCH REQUIRED FOR 240 VOLT CIRCUIT
OH- 33
SWITCH BOX
DOUBLE POLESWITCH
240 VOLTSOURCE
OH-34
TYING A HOLDING KNOT
(d)
159
(e)
or
i1
e
I0
I
II
1I
II
II
1I
°all.il II I 1111la11111°
1I
I.1
4
4, )%
.
rI
OH
-36
r--"
II
1I
a
elRio%
II
II w
Ii..............J
#.-
-r1
ir......... ..... qi1
II
tI
I.110,40.410
II
oI
0I
II
II
II
II
lS
4
N.
./
OD
MP
MD
41=, M
. MD
4=1 M
. 4WP
WO
IM M
. M..
4mosum
.is)
iMilim
lopeaml(D
ING
1LJ
r -- ...... iIIIIIJ
e .........., .. ... .., 1IIIII4
HANDOUT id
SIMPLE SW ITCH
CONTROLLING
A LIGHT
SIMPLE
HANDOUT fl2
THREE-WAY SWITCH
SINGLE POLE - DOUBLE THROW
THREE SCREWS ON THE SWITCH
ONE SCREW - COMMON ORPIVOT TERMINAL
TWO SCREWS - TRAVELERTERMINALS
USED TO CONTROL CIRCUIT FROMTWO LOCATIONS
....... -( NEUTRAL
-
1..
)
3 WAY
HOT SWITCH SWITCH
e--120 V.
165
HANDOUT 113
FOUR-WAY SWITCH
FOUR SCREWS OR TERMINALS
USED BETWEEN TWO THREE-WAYSWITCHES TO CONTROL CIRCUITFROM ANOTHER LOCATION
INSTALLED IN TWO TRAVELER WIRESOF THE THREE-WAY SWITCHES
NEUTRAL
LIG4BU B
SWITCH SWITCH
HOT
6-.120 V.
- 6 is
SWITCH
166
UNIT: Basic Electricity
Lesson 8: calculating Amps, Volts, Resistance, and Cost ofElectrical Power
Need:In order to install and/or maintain a safe and efficientelectrical circuit system, one must understand the powerdenands of the electrical appliances used. Manyelectrical fires and power outages have resulted wher acircuit was overloaded.
Objectives:
1. Given problems dealing with amounts of amperage,voltage, wattage or ohms, the student will be ableto calculate the missing figures by using Ohm's Law.
2. Given a number of electrical devices with theestimated wattage, each student will be able tocalculate how much electricity will have to besupplied to use those devices and how much it willcost over a given period of time.
Key questions, problems Teaching techniques andconcerns information
1. How do amps, volts,and ohms relate toto each other?
2. What is Ohm's Law?
27
a. Amps are a measure ofelectron flow.
b. Volts are a measure ofelectrical pressure.
c. Ohms are a measure 02electrical resistance.
d. The relationship can beexpressed as: "One amperewill flow when pushed byone volt against one ohmof resistance. This iscalled "Ohm's Law".
a. This is an equation usedto find unknown volts,am or ohms.
b.
E = Volts (electricalpressure)
167
3. How are watts calculated?
4. What is electricalhorsepower?
5. What information isneeded to calculateprice of electricityused?
6. What are Demand Rates?
I = Amps (intensity)R =- Ohms (resistance)
c. Handout the ElectricEnergy Computation Wheeland discuss in class.
d. Provide some problems forthe students to use iiapplying Ohm's Law.
e. Volts = Amps x Ohms orAmps = Volts/Ohms orOhms = Volts/Amps
a. Watts-a measure ofelectrical power
b. Watts = Amps x Volts
c. Handout a chart onwattages of selectedappliances.
a. One HP is equal to G )ut
1000 watts.
b. 3 HP motors will drawabout 3000 watts foroperation.
a. Electricity is sold inKilowatt-Hour units.
b. Calculate KWH 's bymultiplying watts x timeand divide by 1000 to getkilowatt hours.Kilowatt hours =
Watts x Hours1000
c. Multiply Kilowatt/hrs bythe company rate to getcost of electricity.
a. In cases where largeamounts of electricity arerequired for short amountsof time, the electriccompany must have theelectricity available foruse. The consumer mustpay extra for thatavailability of
28
168
7. How do you calculatethe amount of electricityneeded for your servicedevices?
8. Estimating amperage needsof a specific houseservice.
electricity.
b. Large irrigation pumps aregood examples of demandcharge rates. (showexample on overhead)
a. Add up all wattages ofdevices and whether theyuse 120 volts or 240 volts.
b. Use Ohm's Law to calculateamperage requirements.
a. Estimate number ofcircuits needed. Theseinclude:1. General purpose2. Small appliances3. Individual circuits
b. General Purpose circuits1. Determine floor area
in square feet.2. Multiply floor area by
3 watts. (NationalElectric Code)
3. Divide by 1500 watts4. Use overhead (0H9) as
an example and showwhen circuits arerecorded.
c. Small Appliance circuits1. Determine locations
where outlets may beneeded. (kitchen)(National ElectricCode requires 2 smallappliances and 1laundry )
2. Divide number ofoutlets by 3 (rule ofthumb fop outlets/circuit)
3. Use overhead and showwhere circuits arerecorded.
d. Individual Circuits1. Most items of
electrical ly operatedequipment should be onindividual circuits.(ex.-range, dryer,
29
169
freezer, washer,etc...)
2. Calculate watts foreach circuit.
3. Show overhead wherecircuits are recorded.
e. Determine the load1. Determine and recordwatts for general
purpose.2. Estimate and record
small appliance watts(1500 watts/circuit-rule of thumb)
3. Record watts forindividual circuits.
4. Find the total watts.5. Find the total watts
needed.a . S i n c e a 1 1
electricalequipment is neverturned on at thesame time, thetotal watts shownis reduced.N.E.C. uses thisformula. First10'00 watts at1 0 0 %. A 1 1
remaining watts at40%.
b. Using the overheadexample:
48000 watts10000 watts
38000 watts
38000 wattsx .A0
15200 watts
15200 watts+ 10000 watts
25200 watts
25000 watts is thetotal estimatedwattage neededfrom the panel.
6. Find the totaleffective load in ampsa. Divide watts
needed by 240
30
170
9. What size serviceentrance panel isneeded?
volts.b. In our example:
25200 watts2T0761ts
= 105amp.
a. Record total effectiveload from step 6 above.
b. Add 20% for future load.
c. Select next higher serviceentrance.
d. In our example:
105 amps x 2n% = 21
105 + 21 = 126 amps
Entrance panels come insizes of 100, 150, 200,and 400 amps.We will need a 150 ampservice entrance.
Application and Followup:
1. Hand out several problems where students will have tocalculate volts, amps, or ohms using Ohm's Law.
2. Hand out several problems where students have to findthe service entrance requirements.
3. Hand out several problems where students have tocalculate the cost of operating equipment for specificamounts of time.
References:
AAVIM, Understanding Electricity & Electrical Terms
AAVIM, Electric Wiring
Sears, House Wiring Simplified Booklet
WATTS
OH-1
120 VOLTS x 1 AMPERE = 120 WATTSC
WHEN YOU COMBINE THE VOLTS AND AMPERES YOU HAVE
A MEASURE OF THE AMOUNT OF POWER AVAILABLE
172
1
S
S
WATTS
.-,.-*::....vi;:i.,-;._;,1-.*::::,_...--;...-.-4`-it.-::..-iif.:4::::::::;«:;..=:2;;:;.:..,
OH-2
..1.::C..t.: *:,intli** '''''';':::it...;.3:- : 4 '11' '....:t .1$ it.:1-.:...2.'.! ... .-.-* .1: -:'.-'..
WHEN YOU DOUBLE THE VOLTAGE TO 240 VOLTS YOU
WILL HAVE TWICE AS MUCH POWER WITH 1 AMPERE
ONE HORSE POWER IS EQUAL
TO ABOUT 1000 WATTS
174
I'M A 1HP. MOTORTHIS IS THE ENERGY
I'LL USE IN 10 HOURS.
Y
..a
DETERMINING THE AMOUNT OF
ELECTRICAL ENERGY USED BY
A dNE-HORSEPOWER MOTOR
175
0H-4
100 WATTS x5 HOURS =500 WATT-HOURS
500 WATT-HRS +1000 =.5 OR' KILO-WATT-HR.
HERES HOW TO DETERMINE THE
ELECTRICITY A LIGHTBULB
USES
176
I REQUIRE ABOUT
120 WATTS .
HERE IS THEENERGY I'LL USE
(OR 15 MIN. WORK.
15 MIN. = % HOUR
120 WATTS x % HOUR =30 WATT-HOURS
30 WATT-HOURS +1000 =.030 KILOWATT-HOURS
SOME APPLIANCL USE MORE
ELECTRICAL ENERGY THAN
OTHERS
177
OH-6
I
0COST OF OPERATING ELECTRIC EQUIPMENT
WATTS X HOURS OF OPERATION= WATT HOURS
WATTS X HOURSKILOWATT-HOURS (KWH)= 1000
FOUR 200 WATT LAMPS= 800 WATTSx 3 HOURS
2400 WATT HOURS
2400 WATT HOURS1000 = 2.4 KWH
ELEC1 AICITY @ 20/K WE!2.4 KWH X 20/KWH= 4.80
OPERATION OF A 2 HP MOTOR (2000 WATTS) =`1
FOR 2 HOURS= 4000 WATT HOURS=4.0 K' iH X 20/KWH= 80
178
173
DEMAND CHARGE
15 HPMOTOR
(15 KILOWATTDEMAND)
THE MOTOR WILL USE $22.50
WORTH OF ELECTRICITY IF
IT COSTS $1,50/KILLOWATT
180
CH-9
CIRCUITS, LOADS AND WIRE SIZES
FOR A SPECIFIC EXAMPLE
WIRE SIZE
CIRCUIT3 NUMBER WATTS VOLTS (COPPER)
GENERAL PURPOSE CIRCUITS:
1800 SQ, FT. X 3 5400 WATTS
5400 t 1500 = 3.6 (usE 4)
SMALL APPLIANCE CIRCUITS:
9 ; 3 = 3 (INCLUDES LAUNDRY CIRCUIT)
3 x 1500 WATTS EACH = 4,500
4 5,400 120 #14
3 4,500 120 #12
INDIVIDUAL:
RANGE 1 10,000 120/240 3-#8
WATER HEATER 1 4,500 240 3-#10
WASHING MACHINE 1 700 120 #12
CLOTHES DRYER 1 5,400 240 3-#10
DISHWASHER 1 1,500 120 #12
AIR CONDITIONER 4 240 #12
HEATERS 8 16,000 240 #12
181
24 48,000
SERVICE ENTRANCE
ENTRANCEHEAD
THREE LEAD WIRESTWO HOTONE NEUTRAL
CONDUIT
METERBOX
NEUTRAL
METERSOCKET
NEUTRALBARTERMINALSCREWS
SINGLEPOLEBREAKER120VBRANCHCIRCUIT
CABINET
...-- ENTRANCE ELL
CONNECTOR
OH-10
HOT
MAINBREAKER
TWO-POLE BREAKER240V CIRCUIT
SPACE FORADDITIONALBREAKERS
CONDUIT
182
HANDOUT #1
HOW MUCH ENERGY
IS BEING USED
El
E2R
I2R
IRI
W
1-
183
HANDOUT #2
APPLIANCETYPICAL
WATTAGE APPLIANCETYPICAL
WATTAGE
Air Conditioner (Room) 1200 Hot Plate 1500Air Conditioner (Central) 5000 Ironer 1850Attic Fan 400 Lamps, Each Bulb 25-200Automatic Toaster 1200 Mechanism for Fuel-FiredAutomatic Washer 700 Halting Plant 800Broiler 1000 Oil Burner 250Built-in Ventilating Fan 400 Portable Fan 100Coffee Maker 1000 Portable Hester 1850Egg Cooker 600 Radio 100Deep Fryer !320 Ranges, Electric 12000Dehumidifier 350 Refrigerator 200Dishwasher-Disposer 1500 Rotisserie 1380Dry Iron or Steam Iron 1000 Roaster 1380Electric Blanket 200 Sandwich Grill 1320Electric Clock 2 Saw, Radial 750Clothes Dryer 9000 TV 350Freezer 350 Vacuum Cleaner 300Fluorescent Lights Ventilating Fan 400
(Each Tube) 15-40 Waffle Iron 1300Griddle 1000 Waste Disposer 500Hair Dryer 100 Water Heater 3500Heat or Sun Lamp 300 Water Pump 700
184
TASK OPERATION SHEET
Task: Making a Rattail Splice
Steps
1.Gatherequip-ment
2.Removeinsula-tion
3.Twistthewires
4.Solderthesplice
5.Tapethesplice
Standard Procedure
a. Pocket knife, electrician'spliers, soldering iron,solid or rosin core solder,plastic top, heat source,steel wool or emery cloth.
a. Using a sharp knife held ata 30 degree angle and par-liel to the wire, remove2" of insulation from thewire ends.
b. Polish the exposed ends ofthe wire if they arecorroded.
a. Hold the two wires togetherto form a "V".
b. Using the electrician'spliers, twist the wire(OH-4)
c. Leave a portion of the endof each wire to bend backover the splice.
Safety & Key Points
a. Note: Thissplice is onlyused when thereis no strain onthe wire.
a. Don't nick thewire whenremoving theinsulation.
b.Steel wool oremery cloth canbe used topolish the wireends.
a. Keep twiststight.
h. Wire ends willnot be bentback over whenusing a solder-less connector.
a. Coat the twisted area with a. Holding thesoldering paste. soldering iron
b. Heat the splice with a under thesoldering iron until it is splice willhot enough to melt the draw the soldersolder. into the splice
c. Hold the solder on the b. Acid coresplice until it is completely solder will eatcovered. the wire.
a. Wipe off any excess flux.b. Using plasti- tap, wrap
the splice so the tapextends beyond the basewire onto the insulation.
32
185
a. Wind the tapetightly.
b. Don't leave anybare wireshowing.
TASK OPERATION SHEET
Task: Installing a Convenience Outlet
Steps Standard Procedure Safety and Key Points
1.Gathertools &equip-ment
2.Barewireends.
3.Connectwhitewire.
4.Connectblackwire.
5.Connectgroundwire.
a. Screw driver, pocketknife, thin nosepliers, new convenience-outlet receptacle.
a. Using a sharp knifeheld at a 30 degreeangle parallel to thewire.
b. Polish the exposedwire ends if they arecorroded.
a. Connect white wire toaluminum colored term-inal port or push thewhite wire into thehole nearest to aluminumcolored terminal port.
b. If second white wire isneeded, connect it tothe second aluminumcolored terminal.
a. Connect black wire tobrass screw terminalor push the black wireinto the hole nearestthe brass colored terminalpost.
b. If a second black wireis needed, connect to thesecond brass coloredterminal.
a. Connect green wire tothe grounding terminalpost.
6.Recheck a. Check eachconnectionconnec- to do determine if theretion are any short circuits.
b. Check to make sure allwire ends are properlyattached.
33
186
a. Be sure to use"UL" approvedreceptacles.
a. Don't cut or nickthe wire.
a. Make certain wireends are bent pro-perly.
b. The extra whitewire will con-tinue the cir-cuit to the nextoutlet.
a. Be sure to fitwire loop ontothe terminalscrew properly.
a. If wiring is veryold there may notbe a groundingwire.
a. Tighten all con-nective wires sothey do not moveabout.
7.Placerecep-tacleinto box.
a. If there is slack wire,bend both wires so theywill "accordian" backinto the box.
b. Replace screw that holdreceptacle in place.
c. Replace receptacle plateand screws.
8.Estab- a. Test receptaclelishelectricityto receptacle.
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a. Adjust receptacleso it is in astraight up anddown position.
b. If receptacleplate is plastic,don't tightenscrews too tight.
TASK OPERATION SHEET
Task: Installing an On-Off Electrical Switch
Steps Standard Procedure Safety & Key Points
1.Gather tools a. Screw driver, pocket a. Be sure to use& equipment knife, thin nose "UL" approved
pliers, new on-off receptacles.switch.
2.Bare wireends
3.Prepareswitch
a. Use a sharp knifeheld at a 30 degreeangle parallel to thewire.
b. Polish the exposed wireends if they are corroded.
a. Don't cut or nickthe wire.
a. Loosen screw term-inals on lew switch.
b. Examine switch tosee which end shouldbe up.
a. Don't removescrews.
b. The "off" and"on" markingshould read rightside up.
4.Connect wires a. Either wire can be a.
to terminal connected to eitherpost. post.
b. Attach the wires aroundthe terminal post in thesame direction thatthe screw tightens.
c. Tighten screw untilsnug, and then tightenan additional half turn.
5.Place switch a.Push switch intoin box. outlet box.
b. Place screws thathold switch in place.
c. Replace switch plateand screws.
6.Establishelectricityto switch.
a. Test switch
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If switch has 4screws or 4insert open:Hgs,be sure to connectwires to oppositesides.
a. Bend wires sothey will"accordian" intooutlet box.
TASK OPERATION SHEET
Task: Making a Western Union or End Splice
Steps Standard Procedure Safety & Key Points
1.Gather a. Pocket knife, electrician'sequipment plier's, soldering iron,and solid or rosin core solder,material. plastic tape, heat source.
2.Remove a. Using a sharp knife heldinsulation at a 30 degree angle and
parallel to the wire,remove 2" of insulationfrom ends to be joined.
b. Polish the exposed wireends if they are corroded.
3.Bend wire
4.Twistwire ends.
5.Solderthe splice
6.Tape thesplice.
a. Don't cut into thewire with theknife.
b. Steel wool oremery cloth can beused to polish thewire ends.
a. Bend each wire to a 90degree angle one inch backfrom each exposed end.(see OH-4)
b. Hook the twc wires together.
a. Grip the wire with apair of electrician'spliers so that one bentend is held by the plierjaws.
b. Twist the free wireend around the secondwire.
c. Reverse the procedure andtwist the second wire.
a. Coat the twisted areawith soldering paste.
b. Heat the splice witha soldering iron untilit is hot enough to meltthe solder.(OH-5)
c. Hold the solder on thesplice until it iscompletely coated.
a. Wipe off excess pasteflux.
b. Using plastic tape, wrapthe splice so that thetape extends beyond thebare wire onto the wireinsulation.
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a. Be sure to wrapthe wires tightlyaround each other.(see OH-4)
a.
b.
a.b.
Holding thesoldering ironunder the splicewill draw thesolder into thesplice.Acid core solderwill eat the wire.
Wind tape tightly.Don't leave anybare wire exposed.
c. Wrap the splice to thethickness of the insulatedwire (OH-5)
TASK OPERATION SHEET
Task: Making On Center or Branch Splice
Steps Standard Procedure Safety & Key Points
1.Gatherequipmentandmaterials
a. Pocket knife, electrician'spliers, soldering iron,solid or rosin solder, plastictape, heat source, solderingpaste.
2.Remove a. Remove at least two inches a. Don't nick theinsulation of insulation from the wire wire.
to which is to be made.b. When removing insulation,
hold knife at a 30 degreeangle parallel to the wire.
c. Remove about 3 inches ofinsulation from the end ofthe branch wire.
3.Twistwire
4.Solderthesplice
5.Tapethesplice
a. Hold the brarch wiretightly against main wire.
b. Twist the branch wirearound the main wireseveral times.(see OH-4)
a. Coat the twisted area withsolderinc, paste.
b. Heat the splice with asoldering iron until it ishot enough to melt thesolder.
c. Hold the solder on thesplice until it iscompletely covered.
a. Wipe off excess paste flux.
b. Using plastic tape,wrap thesplice so the tape extendsbeyond the bare wire ontothe wire insulation.
c. Wrap the splice to thethickness of the insulatedwire(OH-5)
a. Keep loops ofbranch wireclose together.
a. Holding thesoldering ironunder the splicewill draw thesolder into thesplice. .
b. Acid core solderwill eat thewire.
a. Wind tapetightly.
b. Don't leave anybare wireexposed.
3.191Me Of MINT'