nema motor starter requirement by moeller

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Industrial AutomationBuilding Automation Systems

Dipl.-Ing. Wolfgang Esser

Technical Paper

Special considerations governing theapplication of Manual Motor Controllersand Motor Starters in North America



Wolfgang Esser, Dipl.-Ing.

Manager Product Support

Motorstarters & Drives

Industrial Automation Division

Moeller GmbH, Bonn

With grateful acknowledgement

of the support from:

Mr. Andre R. Fortin, BA Phys

Moeller Electric Corporation, Franklin, MA, USA

and

Mr. Dieter Reiß, Dipl.-Ing.

Institute for International Product Safety GmbH, Bonn



Special considerations governing the application of Manual Motor Controllers

and Motor Starters in North America

Page

Recommendations on navigating through this comprehensive technical paper 4Quick overview and summary of contents 4

Product approval requirements in North America 5

Influence of specifiers and users of approved components 6

Requirements of various industrial sales channels for approved electrical equipment 6

Product groupings in North America 8

Manual Motor Controller (Starter) or Circuit Breaker? 8

North American electrical ratings for Industrial Control equipment 8

Installation approvals conducted by electrical inspectors 9

Group installations in accordance with NEC Article 430-53 und CEC Part 1, Rule 28-206 10

• Consequences of Group installation regulations on the proper sizing of Motor Branch Circuit conductors 10

Examples of popular components and combinations in motor branch circuits 11

Additional items worthy of consideration in the North American market with respect to enclosed equipment 11

Basic fundamentals on North American electrical products found in motor circuits 11

• Motor contactors for the North American market 12

- Combination „Contactor + Overload Relay“(Non-combination Motor starter) 12

• Manual Motor Controllers (Starters) for the North American market 14

- Manual Motor Controller (Starter) PKZ 14

- Manual motor Controller (Starter) NZM 14

• Molded Case Circuit Breakers for the North American market 14- Instantaneous-only Circuit Breakers NZM...oBI-CNA 15

- Inverse Time Circuit Breakers NZM..(A)-NA 15

- Inverse Time Circuit Breakers PKZ2..-CB 15

- Advantages of circuit breakers over fuses in North American motor branch circuits 15

• Manually operated disconnect switches in motor circuits 15

Motor Starters in accordance with North American specifications 16

• Combination Motor Starters 18

Various constructive solutions for „Combination Motor Starters“ 18

• Type E Self-Protected Combination Motor Controlle 18

- Self-Protected Combination Starter PKZ2/ZM-.../S-SP 19

- Manual Self-Protected Combination Starter PKZM0-../SP 20

- For applications in the US

- For applications in Canada

- Manual Motor Controllers PKZM0 with large spacing incoming supply terminal BK25-..-E 20

• Type F Combination Starter 22

Tap Conductor Protector 23

Graphic summary in diagram 13 23

Stand 23

Documentation 23

Diagram 13, Motor Starters for North America 24

Useful Tables 26



Recommendations on navigating through this comprehensive technical paper

Readers who are pressed for time and wish to take a quicker road at finding possible answers to their questions are encouraged to skip ahead

to the section entitled “Various constructive solutions for Combination Motor Starters”, indicated in bold in the Index of Contents.

Readers who would like to seek a better understanding of why they need to adopt these solutions for export to North America are encoura-ged to consult the segments under the introductory sections (not in bold in the Index of Contents) primarily dealing with:

• the main features of the North American approval system• the differing guidelines which apply to „Energy Distribution“ and „Industrial Control“ equipment.• fundamental explanations of North American components and assemblies• the varying expectations and demands of Motor Starter assemblies

The technical paper is directed towards planners, project engineers, panel builders and users. A detailed description of tests necessary for theapproval process and a description of specific component design details were purposely omitted. In spite of the thorough approach of this

paper, it deals mostly with specific component related aspects of Manual Motor Controllers and Motor Starters common throughoutNorth America. Comprehensive project design of North American engineered assemblies will require additional and specific knowledge to

that effect.

Quick overview and summary of contents:

The paper clarifies differing concepts with respect to the make-up and application of motor starter switching and protective devices in North

America and the IEC world. Same or similar terms used in both market segments can vary significantly with respect to their proper applica-

tion.

The basis for much of the misunderstanding is rooted in the North American requirement and custom of specifying separate upstream pro-tective devices which comply with more stringent standards, such as UL 489 and CSA-C22.2 No. 5-02, ahead of motor starter equipment which

fulfills UL 508 and CSA-C22.2 No.14 industrial control standards. As a rule, North American product standards like UL 489 and CSA-C22.2 No.5-02 specify significantly larger creepage and clearance distances on the equipment than the corresponding IEC/EN guidelines.

For machine manufacturers and panel builders who export and wish to standardize on one solution for machinery and its associated electri-cal equipment, the following list of fuseless „Combination Motor Starters“ represents a number of viable options which are equally applica-

ble in the IEC world:

• Type E Self-Protected Combination Motor Controller- Self-Protected Combination Starter PKZ2/ZM-.../S-SP - Manual Self-Protected Combination Starter PKZM0-../SP

- Manual Motor Controllers PKZM0-.. with large spacing terminal BK25-..-E

• Type F Combination Starter

In such cases, however, it is necessary to keep in mind that North American engineering guidelines and specifications related to the equipment,including the use of North American wiring materials, must be strictly followed and adhered to. Voltage levels can be easily adapted with the

use of applicable matching transformers.Diagram 13, found at the end of this paper, details the structural composition of various starter solu-tions und their ability to comply with application requirements.

These solutions should make it much easier to resolve what has been up to now two separate versions of electrical controls for machinery, i.e.

one for North America and the other for the IEC , since the general structural layout of both panels can now become more or less the same, if

not totally identical. As indicated, the use of fuseless equipment is especially recommended for the export to North America since it will eli-

minate all problems arising from the use of differing and localized fuse based systems and the larger dimensional panel size requirementswhich they generally entail.

As the paper clearly shows, the general topic of product approvals is rather complex. It is in a constant state of flux and changes must be moni-

tored closely and diligently. There are so many details vital to the user which only the manufacturer will be in a position to know. Moeller hasthe specialists in place who can keep you abreast of developments and provide you with the necessary engineering and design help, as well

as localized support and start-up assistance directly in North America. And lastly, Moeller can design and build for you complete control panels,listed and labeled for problem free installation. You can put your trust in the experience we have accumulated over decades of involvement

in the North American market place; product and assembly approvals have always been a Moeller specialty

Dipl.-Ing. Wolfgang Esser

Moeller GmbH, Bonn

4



Differing product standards and marketcustoms in Europe (IEC -Guidelines) 1 and inNorth America (NEC / CEC ) 2 can often leadto frustrating delays or costly and extensivealterations of European engineered assem-blies exported to North America (e.g. con-trol panels for machinery). Conversely, inNorth America, there are only minor diffe-rences between the prevalent standards inboth the US and Canada which cover suchinstallations. These slight deviations will behighlighted further into the paper. Thisdocument will attempt to point out thesediffering viewpoints and hopefully assist inpreventing misunderstandings, irritating

delays and costly reparations which mayotherwise occur. In view of these realities weremain in constant touch with local approvalauthorities and with our Moeller subsidia-ries in North America, who always keep usabreast of the latest developments in thisrespect.

The term „Motor Starter“, already in use inAmerica for many years, has even to a largeextent been adopted in Germany, albeitwith a somewhat differing interpretation.The IEC / EN 60947-4-1 [1] standard hasmostly led its introduction into the localEuropean and German vernacular. Among

many motor starter related topics, this stan-dard concerns itself with the necessary coor-dination, effect and consequences of short-circuits on combinations of contactors andoverload relays, as well as on manual motorstarter performance requirements.

Motor starters designed in accordance withinternational and European standards(excluding North America), and marketed byvarious control gear manufacturers, gene-rally share a similar construction and havebeen successfully applied by the millionsworld-wide. It’s interesting to note in thisrespect that in North America there is a very

established market for European products,particularly in the machine tool industry andthe export of engineered assemblies back toEurope. For that reason, European productsand control panel design engineering philo-sophies have become well known andappreciated throughout North America.

Still, there is often a general lack of know-ledge in North America of technical innova-tions originating out of Europe, but this isnot necessarily due to a failure by the EU ofsuccessfully passing North American appro-val testing for newer product designs andtechnological breakthroughs. Rather, it hasmore to do with the likelihood that thereisn’t yet a North American standard in placewhich can adequately provide suitable andappropriate testing for these new designs,and which would allow recently introducedproducts to take full advantage of theirapplication possibilities, as is the case in theEU. (refer to the section on various Motor

Starter constructions). Conformity withinternational norms, as well as practicalapplication knowledge derived from yearsof positive field experiences, are simplyinsufficient to verify compliance with localNorth American electrical Codes. Thus, is itproper to conclude that we are dealing withNorth American trade restrictions meantspecifically to exclude European goods infavor of protecting functionally equivalent,but dimensionally larger North Americanproducts? Consider that there is a proposedstandard on the table entitled UL 60 947 [2].That number, not coincidentally, is wellknown within the international and Euro-

pean communities and is identified with lowvoltage equipment design guidelines andproduct performance standards. MotorStarters are equally grouped under the samefamily reference number. The outcome ofthis North American draft standard is, there-fore, eagerly anticipated.

Product approval requirements

in North America

In the US, product approvals and listings are

mandated by the government agencyOSHA3 and the NEC , which require third party cer-tification or “listing” of electrical productsand engineered assemblies by independentand nationally recognized testing laborato-ries (NRTL) 4, e.g. UL 5. In Canada, all electri-cal equipment must comply with the CEC 6,

and CSA certification is a legally bindingrequirement for all electrical products andassemblies.

Approval requirements in North America areclosely associated to third party certificationmarks which must appear on products tovalidate this claim. Devices which have beensuccessfully tested will therefore be affixedwith an appropriate laboratory stamp ormark. (Table 1). In the US, a cataloging oflisted and recognized products can be refe-renced in the „Electrical ConstructionsMaterials Directory“ and the „RecognizedComponent Directory“ respectively. (refer to

the section: Product groupings in NorthAmerica) In Canada, product registrationscan be found in the „List of certified Elec-trical Equipment“.

As a result of relaxed trade restrictionsbrought about by the NAFTA-Agreement 6

there is now the possibility of submittingproducts to either UL or CSA for simultan-eous coverage under both standards. Theseproducts would then bear only one listing orcertification mark, which should theore-tically, and legally, be acceptable in bothcountries. However, because of continuingreluctance on the part of local inspectors

(refer to the section on this further on down)and unfamiliarity of end-users to recognizeand accept this common listing, Moelleronly very rarely resorts to using that option.

Moeller has adopted two product relatedsolutions with respect to approval require-ments:

• In cases where both the North Americanand international requirements can resultand be unified under one design, Moellerrefers to those products as „World Marketdevices“, which signifies that these pro-ducts are in compliance with all pertinent

approvals and can therefore be success-fully applied world wide. (Examples ofthese include e.g. contactors, overloadrelays, pushbuttons and pilot devices, forwhich the basic IEC design is also additio-nally affixed with North American appro-val listing and certification marks)

1 IEC = International Electrical Commission2 NEC = National Electrical Code

CEC = Canadian Electrical Code3 OSHA = Occupational Safety and Health Act (http://www.osha.gov)

4 NRTL = Nationally Recognized Testing Laboratories5 UL = Underwriter‘s Laboratories (http://www.ul.com)

6

CEC = Canadian Electrical Code7 CSA = Canadian Standards Association (http://www.csa.ca)

8 NFTA = North American Free Trade Agreement

Special considerations governing the application of ManualMotor Controllers and Motor Starters in North America

5



• In cases where the North American andinternational requirements cannot resultand be unified under one design, or whenproduction volume of components isstrictly monitored by third party authori-ties and subject to additional inspectioncosts, Moeller must adopt as a recoursetwo or even possibly three different ver-sions of the same product. (Circuit Brea-kers are a good example). These productsneed to undergo certain modifications inorder to comply with the North Americanstandards and are correspondingly identi-fied with the suffix „-NA“ or „-CNA“. Only

these North American types are subject toreexamination requirements stipulated bythe approval authorities. From a designpoint of view, these devices are onlyslightly different from their IEC counter-parts, and in some cases are identical.

In the US there is a further differentiation,highlighted in Table 2, between „ListedIndustrial Control Equipment“ and „Recog-nized Component Industrial Control Equip-ment“. Each type is identified with respec-tive markings on products.

Influence of specifiers and

users of approved components

In Europe, people are familiar with so-calledinstallation standards, like e.g. the IEC/EN 60204-1 [3] (Electrical apparatus for machi-nery), which are layered with many applica-tion based requirements that cannot beaccomplished solely by a manufacturer’scomponent design. The responsibility forcompliance, therefore, goes beyond theactual component and extends to thedesign engineers, panel builders, contrac-tors and users alike.A similar sharing of responsibilities in thisrespect also exists in North America and isclosely tied in to the approval process. Amanual motor starter Type PKZM0, as acomponent, is UL listed and CSA-certified.That is certainly an important part of the pic-ture, but not the only criteria for successfuland proper application in North America.These manual motor starters, (or „manualmotor controllers“ as they are referred to inUL /CSA standards) are simply not allowed tobe applied in North America to the fullextent of their performance capabilities, asthey are and have been by the millions in theIEC world successfully. This is an importantpoint to always keep in mind. (refer to thesection: Various constructive solutions for„Combination Motor Starters“). It’s ourintent, therefore, to always make this clearin order to insure that products that are

approved are also being applied properly,and within the guidelines laid down by thelocal North American electrical codes.

Requirements of various sales

channels for approved

Industrial Control equipment

Moeller considers the following sales chan-nels to be its primary outlets for approvedcomponents and assemblies:

• Direct sales in North America

- For applications in North America

In this case, approvals are a must. Eventhen, listed and certified IEC componentsin many instances represent to the localbuyer at best a compromise to their pre-ference for NEMA products and philoso-phies. That makes it a harder sell for IEC type equipment. On the other hand,there are a number of applications forwhich smaller physical dimensions, cou-pled with a fuseless design approach, or

even almost fuseless, provide Moellerwith an excellent opportunity for secu-ring business. That is especially the casewhen Moeller is not only supplying com-

6

MoellerType suffixadded to thepart number Typ of Approval Approval marks

-NA The device is fully UL listed or CSA certi-fied as a stand-alone component.

FORM CDN The device is only CSA certified asa stand-alone component.

FORM USA The device is only UL listedas a stand-alone component.

-CNA The device is component recognized byUL, and its proper application is subjectto conditions of acceptability. (Table 2)

The device is CSA certifiedas a stand-alone component.

Table 1: Various approval variations used by Moeller along with the corresponding marks which

appear on the respective products. Refer also to Table 2.

Table 2: In the US, industrial control equipment failing under UL 508 can be categorized as „Listed

Industrial Control Equipment „ and „Recognized Component Industrial Control Equipment „

Listed Industrial Control Equipment

No restrictions in terms of application

Recognized Component IndustrialControl EquipmentApplication based on conditions of acceptability

• Devices listed for „field wiring“• „factory wiring“ is covered by

„field wiring“ provisions

That means:- Suitable for control panels, and

considered complete for field wiringin factories or panel shops

- Comonent sales in the US isunrestricted and not subject to anyspecial acceptability considerations.

• As components, products are suitablefor „factory wiring“

That means:- Component selection is conducted

by trained personnel and subject toConditions of Acceptability

- For use in control panels; designed,wired and tested by technicallytrained personnel in appropriatefactories and panel shops.

Mark: Mark:



ponents, but also engineered products,such as control panels for industrialmachinery and the like. These types ofapplications have another side benefit inthat much of what is learned is fed backinto the design department in Germanyand thus positively influences currentand future product developments.

- For export out of North America

For these applications there is an over-whelming demand for IEC based designsand the smaller dimensions they entail.That’s especially the case whenever engin-eered assemblies can be exported as IEC based equipment. In this instance, NorthAmerican component approvals havelittle significance. However, for obviousreasons, there is a definite tendency onthe part of North American exporters toseek and standardize on equipment thatconforms to both North American andIEC standards. It’s an important salesargument, therefore, for components tobear the CE -Mark9, particularly whenthey are subject for export to Europe.

• The export business to North Americafrom IEC-countries

This type of indirect export business forMoeller involves mainly machinery and asso-ciated electrical controls, which typically are

built in Germany or in the rest of Europe. Insuch cases, the exporting machine manufac-turers are keen on building either series pro-duction machinery with the same electricalcontrol scheme that hopefully will be suit-able world-wide, or, with an electrical con-trol panel which may only vary slightly toaccount for North American code require-ments. North American machine buyers arenot only appreciative of European expertisein machine building, they also recognizemany of the technological advantages thatmodern European electrical controls offer aspart of the package. A fuseless design isalways preferred, and is amongst the most

important characteristics of a modern elec-trical control panel. It’s also recommendedfor export purposes to use switching equip-ment which can be used in both 50Hz and60Hz supply systems. Nominal voltage diffe-rences can be easily taken care of with trans-formers. Export business is where Moeller’sconsiderable experience and comprehensiveknowledge really come to the fore. In short,the main goal is to design an electrical con-trol panel which will maximize the use ofEuropean technological know-how and stillbe guaranteed approval by the local electri-cal inspection authorities . This applicationrepresents the single largest requirement for

IEC style components, which are exactly thetype which Moeller has been designing andmanufacturing for decades. It’s also extre-mely useful for machinery exporters that

Moeller is able to build fully labeled NorthAmerican style control panels in its ownUL / CSA authorized factories. Furthermore,Moeller can provide competent field serviceassistance through its subsidiaries in NorthAmerica which can also handle spare partsreplacement business.

Product groupings

in North America

In the US and Canada, as is shown in greaterdetail in Table 3, there is a marked diffe-

rence in many respects between compo-nents designed for use in feeder circuits(energy distribution) and those that are typi-

Table 3: North American product grouping differences and delineation of safety standards

Product Groupings in North America

Components for energy distribution

(Distribution Equipment)

Components for motor control

(Industrial Control Equipment)

UL 489 und CSA-C22.2 No. 5-02 UL 508 und CSA-C22.2 No.14

• Molded Case Circuit Breakers

• Molded Case Switches

• Safety switches (UL 98)

• Fusible Disconnect Switches (UL 98)• Fuses (UL 248)

ULq CSA equivalent standards:

UL 98q CSA-C22.2 No. 4

UL 248q CSA-C22.2 No. 248

• Magnetic controllers (contactors)

• Control Relay

• Overload Relays

• Manual Motor Controllers (protectors)• Rotary Cam Switches

• Pushbuttons and Pilot Switches

• Solid State controls and systems

• Programmable Controllers

Special requirements:

• These devices need to be particularlyrobust in their construction and featurelarger electrical spacings than standard

equipment:

(for 301...600 V: 1 Inch through air,

2 Inches over surface).

• Lower permissible temperature rise(50 °C).

• Product design more divergent thanIEC equivalent.

• Incoming and outgoing feeder compo-

nents for energy distribution assemblies(Switchgear, Switchboards, Panelboards)

must conform to these standards.

• Main disconnect and protective

switches used in industrial controlassemblies must also conform to

these standards.• Safety testing for these products

maintain strict standards and factoryproduction quality is closely monitored

by inspectors from each approvalauthority.

• UL/CSA Molded Case Circuit Breakertesting standards are amongst the most

stringent in the industry world-wide.

• Quarterly and extensive re-examination

testing as a function of production.

Special requirements:

• These components are smaller in sizeand electrical clearances are not aslarge as those of energy distribution

equipment.

• Industrial control devices are installed

primarily in control panels, in motorbranch and associated load circuits,

in Motor Control Centers (MCC ) andalso as components in some energy

distribution assemblies.

• They can be combined in the same

circuit as energy distribution equipmentin control panels, e.g. with a circuit

breaker used as a main disconnectand protective switch in a motorbranch circuit.

• Factory production is also monitored

by the approval authorities, but not

to the same extent as applies to circuitbreakers.

• Generally speaking, more compatible

with conventional IEC -designs.

79 Conformité Européenne, the mark allows com-ponents unrestricted access to markets in EuropeanCommunity countries.



cally found in motor branch circuits (indus-trial control equipment). These two productgroupings are subject to a totally differentset of evaluation standards, which entail adifferent level of testing requirements andperformance criteria. It’s crucial to keepthese two categories in mind as they willcome up often in this document and are acrucial link in properly understanding thedivergent ways in which motor protectiveswitches and circuit breakers are evaluatedper the North American standards. Bothproduct groupings will be frequently refer-red to in the ensuing text.

Manual Motor Controller

(Starter) or Circuit Breaker?

The term „Motor Protective Switch“(manual motor controller) was coined byMoeller years ago in Germany. The Moellerpart number PKZM to most electricians issynonymous with motor protective swit-ches, regardless of manufacturer. Moellerhas been manufacturing these manual swit-ches since 1932. Competitors equally referto their devices of the same construction as„Motor Protective Switches“ or they talkabout “Circuit Breakers”, regardless ofnominal current ratings.

The term „Motor Protective Switch“ is actu-

ally not spelled out quite that way in the per-formance standards and IEC -guidelines.However, all understand the device to be a 3phase, normally manually operated circuitbreaker for nominal currents up to 63A,which has been optimized for the protectionof electric motors. According to interna-tional norm classifications it belongs to thegroup of „current sensitive, thermally de-layed (inverse time) overcurrent protectivedevices“. This norm recognizes overloadrelays (with relay outputs) or overload trip-ping elements, which are functionally desig-ned to interact with the switching mecha-nism and thus have a direct impact on the

operational state of the main power con-tacts. These main contacts can also be usedfor the occasional direct-on-line switchingof motors. In cases where a higher degree ofswitching frequency is necessary, the motorprotective switch is combined with one ormore magnetic controllers (contactors). Themotor protective optimization featuresmentioned earlier mostly refer to the provi-sion for phase failure sensitivity in accor-dance with IEC / EN 60 947-4-1 [1] and thecapability of handling AC-4 type currentswithout nuisance tripping for the durationof the motor start-up sequence. Generallyspeaking, a phase failure sensitivity feature

for circuit breakers, which are frequentlysubject to uneven loading across the phases,could be problematic since it could lead tonuisance and unwarranted circuit breaker

tripping. For nominal current ranges excee-ding the range of motor protective switches,Moeller offers circuit breakers with an optio-nal phase failure sensitivity feature .

In addition to the overload protective func-tion, motor protective switches built inaccordance with the international standardsIEC / EN 60 947-1 [4], IEC / EN 60 947-2 [5]and IEC / EN 60 947-3 [6], also include mag-netic trips for short circuit protection andisolating capabilities. In accordance with thedemands of IEC / EN 60 204-1 [3] thesemotor protective switches must also, withthe use of accessories, be able to fulfill therequirements of a Main Disconnect switch.The short circuit protective function, the iso-lating characteristics and the Main Discon-nect function are only minimally recognizedper the North American standards (see en-suing sections for further clarifications).

North American electrical

ratings for Industrial Control

Equipment

The US and Canadian standards have defi-ned various types or categories of switchingduty requirements for industrial controlequipment in similar fashion to the IEC andnational standards which define „Utilizationcategories for low voltage switching devi-

ces“ (AC-1, AC-3, AC-4 etc.). Each „LoadType” in North America is assigned a Loadduty rating as indicated in Table 4, whicheither appears on the rating label of eachdevice or in technical data sheets suppliedwith the product, and identifies its suitabilityfor the respective loading requirements.

It’s important that these load duty classifica-tions be strictly observed in all cases forexport to North America, particularly sincein many instances the North Americanratings can be lesser than their IEC equi-valent.

Please consult the special Moeller catalogentitled „Approval for World Markets“(SK0200-1043 D) for detailed and currentinformation on the approval situation inNorth America and the global market-place, as well as more comprehensiveinfo on products specifically approved forthe North American market.

Installation approvals conducted

by electrical inspectors

Generally speaking, there is a great deal ofuncertainty on the part of North Americanelectrical inspectors with respect to equip-ment imported from overseas. That aspect,combined with a fundamental lack of know-ledge of North American standards on the

Switching load categories (Load duty ratings)

Load Duty Rating,Marking on raiting label

1) Motors Horsepower

2) Coils Code Designation, Voltampere, Stan-dard Pilot Duty or Heavy Pilot Duty

3) Resistance (heating) Amperes, Resistance only

4) Incandescent lamps Amperes or Watts, tungsten

5) Ballast (electric discharge lamps) Amperes, ballast

6) General Use * Amperes(A)

* The group „General use“ applies for general usage, and in accordance with theIEC utilization category AC-1.

Table 4: Types of switching loads (Load Duty ratings)

8



part of European machinery exporters, inva-riably cause frequent misunderstandingsand commissioning delays for any equip-ment being newly brought on line. Theinspectors ( AHJ -Authorities Having Jurisdic-tion) are local town and county governmentemployees who are empowered to insurethat electrical installations are properly eva-luated and in compliance with local Codesand ordinances, which are primarily derivedfrom the NEC . The evaluation conducted bythese electrical inspectors is a vital link inultimately determining whether or notpower to the installation can be furnishedby the local utility company. A sanction bythe inspection authority is also necessary forinsurance coverage to be granted or exten-ded to the building owners.

The provisions of the NEC require that allelectrical components and assemblies be“listed” by third party approval authorities(NRTL - Nationally Recognized Testing Labo-ratories) like e.g. UL. The inspectors dependheavily on the use of UL listing and UL markson products to conduct their evaluation

work, simply because it greatly minimizesthe approval risk they would otherwise haveto undertake if the equipment were uneva-luated. A similar situation exists in Canada.A case could certainly be made that inspec-tors are generally more wary and critical offoreign equipment, and that there is a vary-ing degree of tolerance among them as towhat they would deem to be acceptable.Nevertheless, there is always a keen intereston the part of inspectors to look for, and fin-ding, the familiar UL and CSA marks on allproducts, and to make sure that the productis applied properly per its North Americantechnical ratings. It’s also helpful in theirview to be confronted by a panel layout andwiring schematics which conform to localconventions and expectations. It can’t beemphasized enough that exporters mustpay close and strict attention to North Ame-rican requirements, because evaluation pro-blems with electrical inspectors can haveserious consequences and must be avoidedat all costs. When it comes to the export ofproduct to North America it’s never a goodidea to assume that everything will go

smoothly on the theory that „nothing badhas happened to me yet“. Rather, it’s a verysafe bet that a policy of avoiding local elec-trical code compliance issues will, soonerthan later, backfire badly and cause hardshipto both exporter and end-user alike. In linewith their philosophy of supplying „morethan products“, the Moeller Companyoffers a number of consulting sessions anddetailed customer seminars on the subjectof North American standards and approvals.Our sales offices will be more than happy toput you in touch with the right people.

An important guide for the evaluation workof electrical inspectors can be found indiagram (430-1) from the NEC (Diagram 1).This diagram will also be the basis for manyof the clarifications provided.

Note that the current NEC has switchedfrom using letters to denote Part A throughPart J to roman numerals Part I throughPart IX.

Diagram 1: Diagram 430-1 from the National Electrical Code points out the important elements of the Motor Branch circuit. Differences between interna-

tional and North American definitions of key terms are the basis for much of the misunderstandings and problems which can occur during equip-

ment evaluation by North American inspection authorities. A similar diagram is also found in the CEC .

old Part/ new Partalt/neu

Part B430-24

430-25, 430-26Motor feeder

Motor feedershort-circuit andground-fault protection Part E

Motor disconnecting means Part J

Motor branch-circuitshort-circuit andground-fault protection Part D

Motor circuit conductor Part B

Motor controller Part G

Motor control circuits Part F

Motor overload protection Part C

Part C

Motor Part A

Thermal protection

Secondary controllerSecondary conductors

Part B430-23

Secondary resistor Part B430-23 and Article 470

To Supply

/II

/V

/IX

/IV

/II

/VII

/VI

/III

/I

/III

/II

/II

9

National Electrical Code - Motor CircuitsNEC Article 430 - Diagram 430-1

Main Disconnect

Short Circuit

Motor Controller

Overload



The Code requires that the Motor Branchcircuit include 4 basic functions:

• Main Disconnect• Short Circuit protection• Motor Controller (Contactor)• Motor Overload protection

The main difference in the evaluation is thatthe conventional and European style motorprotective switches, like PKZM or similardevices, are approved in North America as„Manual Motor Controllers“ only and canonly fulfill a motor overload protective func-tion, even when they are additionally evalu-ated for group installations. Devices of thisconstruction and approval are not conside-red as short circuit protective devices by theinspection authorities. (Exceptions later.)

Group installations per NEC ,

Article 430-53 and CEC Part 1,

Rule 28-206 („Group Protection“)

Generally speaking, in a North Americanmotor starter, the main disconnect and shortcircuit protective functions are fulfilled by anupstream switch. This consists of either a cir-cuit breaker (Energy Distribution Equip-ment per UL 489, CSA-C22.2 No. 5-02) or afusible disconnect switch (UL 98, CSA-C22.2No. 4). These branch circuit overcurrent

protective devices are usually mounted

separately.The North American HVAC (Heating, Venti-lation and Air Conditioning) industry wasmostly responsible for pushing throughGroup Installation regulations through theNEC/CEC years ago. Group Installation refersto the practice of setting up a number of tapcircuits, each with a motor controller andmotor overload protective device, underone back-up (group) branch circuit overcur-

rent protective device. This regulation also

permits the use of manual motor starterssuch as PKZM , when they are used for theoverload protective function or as a manu-ally operated motor controllers incorpora-ting motor overload protection.Moeller contactors and motor overloaddevices, for example the manual motor star-ter PKZM0 in this case, must be specificallyapproved for Group Installations. All manualmotor starters in the PKZM0 and PKZ2/ZM

ranges are UL listed and CSA certified forthis application per the NEC/CEC and can bethus grouped under one overcurrent protec-tive device. PKZM0 manual motor startersup to 6.3 Amps , per Table 5, can be used incircuits with an available fault of up to 50kAand a back-up switch as high as 600 Amps.For the largest setting ranges of the PKZM0the short circuit and back-up value ratingsare 10 kA and 150 A respectively.(Caution: From the European standpoint,one understands group protection to meanone protective device protecting many loads(Diagram 2), e.g. a number of contactorsand overload relays.)

• Consequences of Group installationregulations on the proper sizing ofMotor Branch Circuit conductors

There are also specific rules in Europeanand international standards governingproper selection and co-ordination of con-ductor cross-sections and overcurrent pro-tective device ratings. A strict set of condi-tions must be observed if one is permittedto reduce the cross- section of a conduc-tor with the same upstream device, simplybecause the overcurrent protection set-

ting could end up being oversized for thesmaller conductor. The same reasoningapplies with respect to North Americanselection guidelines. In group installations

Diagram 2: Misunderstandings can arise from differing interpretations of Group Protection.

Table 5: Maximum sizing of back-up protective devices and maximum available fault ratings for group

installations per NEC Article 430-53 and CEC Part 1, Rule 28-206. Values with and without

additional fueseless current limiter accessory.

Note: In the near future, UL may change the rules regarding the maximum permissible value of back-

up protective devices to be marked on controllers to be more in line with current NEC pratices.

As of this writing, above values still apply.

Maximum permissibleGroup protective device

Maximum availablefault currentat 480 / 600 V

Without Current

Limiter CL-..With Current

Limiter CL-..Without Current

Limiter CL-..With Current

Limiter CL-..

PKZM0-.. up to 6,3 A 600 A 50 / 50 kA

PKZM0-10, -16 150 A 600 A 10 / 10 kA 50 / 50 kA

PKZM0-20, -25 150 A 600 A 10 / 10 kA 18 / 18 kA

PKZM0-../SP up to 11 A 50 / 50 kA

PKZM0-16/SP 42 / - kA

PKZM0-25/SP 18 / - kA

PKZ2/ZM2-.. 500 A 65 / 42 kA

PKZ2/ZM2-.../S 2000 A 65 / 42 kA

PKZ2/ZM2-.../S-SP

up to 27 A– – 65 / 42 kA

PKZ2/ZM2-.../S-SP

32 and 42 A– – 65 / - kA

10

Group Installations

North American perspective

Back-up protectivedevice

(NZM OBI /PKZ...)

(PKZ) (DIL/Z.)

European perspective



per NEC/CEC , the general rule is the ampa-city ratio between incoming feeder con-ductors and outgoing supply cables can-not exceed 3:1 (1/3 rule). (Diagram 3).There are additional possibilities to reduceconductor cross-sections in such installa-tions with the use of (Type E) “Self-Protec-ted Combination Motor Controllers“ and„Tap Conductor Protectors“. Tap Conduc-tor Protectors, as explained later, canrepresent a suitable alternative to the useof Type E Combination Motor Controllers.

Examples of popular compo-

nents and combinations in

Motor Branch Circuits

Table 6 details the evaluation of severalpopular component combinations in motorbranch circuits from the perspective ofNorth American electrical inspectors andDiagram 1 (NEC-Diagram 430-1).

Additional items worthy of

consideration in the North

American marketplace with

respect to enclosed equipment.

International IP..-environmental ratings forenclosures are not recognized by electrical

inspectors. A North American environmen-tal rating in accordance with NEC 430-91 / CEC must appear on the enclosure, and inthe case of door mounted components, onthe product itself or on the accompanyingtechnical documentation. Conduits contai-ning incoming and outgoing conductors areterminated and fastened directly onto theenclosure. Conduits are offered in various“NPT ” (National Pipe Thread) Trade Sizes.European PG-fixtures or metric Conduits are

unknown. For that reason, Moeller offersproduct dedicated insulating material enclo-sures CI-K2-PKZ0-NA-G(R)(V) with smoothsided bases and drill starts to betteraccommodate cable entries with NorthAmerican style NPT trade size conduits. Iffuses are involved, particular attention mustbe paid to local fuse based systems and cha-racteristics. In addition, all wiring material

for assemblies must be approved per NorthAmerican standards (UL/CSA) and conductorcross-sections must be selected in accor-dance with North American Code regula-tions.

Basic fundamentals on North

American electrical products

found in motor circuits

Since evaluation criteria and applicationpossibilities for low voltage equipmentdesigned per North American and inter-national guidelines can vary so much, cer-tain aspects need to be briefly presented. It’snecessary to know these differences in orderto properly understand the special conside-rations involved with the proper applicationof motor starters in North America.

By design, electrical motors in North Ame-rica are assigned load duty ratings referredto as Service Factor (SF). The overload pro-tective settings Ir of overload relays, manualmotor starters or circuit breakers need totake motor service factor into account inorder to provide the motor overload trip-ping protection required by Code. The needfor a corrective factor can be easily accomo-dated by selecting the appropriate settingrange on the motor overload protective

Diagram 3: Maximum ratio between incoming supply and outgoing motor circuit conductors in group

installations

Table 6: Evaluation of various motor protective and circuit breaker combinations of European design, from the perspective of North American electrical

inspectors and Diagram 430-1 of the NEC. These combination types are further explained in the body of the text.

UL listed / CSA certified Components and Combinations

Evaluation per Diagram 1 NEC 430-1,

Part J resp.Part IX

Part D resp.Part IV

Part G resp.Part VII

Part C resp.Part III

MainDisconnect

Short Circuitprotection

Controller(Contactor)

Overloadprotection

1 Inverse Time Circuit Breakers NZM.../ZM(A)-...-NA Yes Yes No No

2 Manual Motor Starter with magnetic contactorPKZM0-.../S(E)00, PKZ2/ZM-…/S

No No Yes Yes

3 Motor Controller PKZ2/ZM-…/S-SP

Type E Self-Protected Combination Motor Controller

Yes Yes Yes Yes

4 Instantaneous only circuit breaker + magnetic contactor

+ overload relay NZM...OBI-CNA + DILM + Z

Yes Yes Yes Yes

11

(PKZ)

Ratio betweenincoming supply andoutgoing cables3:1 (1/3 Rule)

Branch Circuitprotective device



devices and adjusting accordingly. The follo-wing values apply:

SF = 1,15 h I r = 1 x I n mot

SF = 1 h I r

= 0,9 x I n mot

• Motor contactors for theNorth American market

Motor contactors in North America areindustrial control devices (Industrial Con-trol Equipment per UL 508 and CSA-C22-2No. 14). North American buyers specifyeither contactors with so-called „NEMA-Sizes“, or they purchase components spe-cifically for motor switching, which arerated in (HP) Horsepower and can be morecustomized for the application. Table 7shows the relationship of power andnominal current ratings corresponding toeach respective NEMA-size.Moeller contactors Type DILEEM throughDIL2AM, and matching Type Z overload

relays, each have a basic short circuitrating of 5 kA. Larger Moeller contactorsstarting with the DIL3M80 have, togetherwith their corresponding Type Z overloadrelays, a shorth circuit rating of 10 kA.

- Combination “Contactor +Overload Relay”(„Non-combination Motor Starter“)

NEMA-sizes, as they relate to the HPratings of Moeller contactors, are provi-ded in Tables 8a and 8b. Contactors andoverload relays make up an assembly thatis referred to in North America as a „Non-combination motor starter“ . For theseassemblies, namely consisting of “Contac-tor + Overload Relay”, the North Ameri-can buyer specifies the same orderinginformation as it applies to individual con-tactors. Tables 8a and 8b clearly indicatethat, with respect to all common nominalvoltage levels, the combination of „IEC style“ contactors DIL M with overloadrelays Type Z create many more starter

combinations than corresponding straightNEMA sizing would allow for.

(According to European understanding these

combinations (with overload relay), with very

few exceptions, would be combined with

fuses as short circuit protective devices, and

then would be labeled as fusible or “fuse

based” motor starters accordingly.)

• Manual Motor Controllers (Starters)for the North American market

- Manual Motor Starters PKZAs components, manual motor startersare Industrial Control devices that aretested and UL listed per UL 508 and CSAcertified per CSA-C22.2 No.14. ThePKZM manual motor starters are worldmarket devices. They feature fixed in-stantaneous trips (PKZM0 und PKZM4) oradjustable magnetic trips (PKZ2) for shortcircuit protection, adjustable bimetaltrips for motor overload protection andthey can switch motors directly across theline. They can also be equipped with

Three PhaseNEMA Contactors

NEMA-Sizes

Rated Current Three Phase HP ratings 1)

200 V / 60 Hz 230 V / 60 Hz 460 V / 60 Hz575 V / 60 Hz

Highest short timeduration current

A HP HP HP A

00 9 1 m 1 m 2 11

0 18 3 3 5 21

1 27 7 m 7 m 10 32

2 45 10 15 25 52

3 90 25 30 50 104

4 135 40 50 100 156

5 270 75 100 200 311

6 540 150 200 400 621

7 810 - 300 600 932

8 1215 - 450 900 1400

9 2250 - 800 1600 2590

1) HP ratings for 3-Phase contactors, single speed motors, with no jogging, reversing and

dynamic current braking.

Table 7: NEMA-Sizes for contactors in relation to HP -ratings and rated nominal current levels.

12



Table 8a: Selection chart for North American „Contactor + Overload Relay“ combinations

Maximum Short Circuit Protective device

for North America

Overload RelayPossible Combinations

Inverse Time Circuit

Breakers NZM(H)...A

Contactor max.

O/L Relay

Rating data for combinations

Maximum Motor HP ratings

Max.

Motor

Full

LoadCurrent(FLC )

Fuses

CEC/CEC

AmpereRating

Max.instantaneoustrip setting

Plugged

intocontactor

Separately

mounted

with

Adapter EZ

Approvals

Type

Type

200 V

HP

230 V

HP

460 V

HP

575 V

HP A A A A Canada USA

DIL EEM

DIL EEM

DIL EEM

DIL EEM

DIL EEM

DIL EEM

ZE-1

ZE-1,6

ZE-2,4

ZE-4

ZE-6

ZE-9

-

-

m

-

-

1 m

-

-

m

1

1 m

2

m

o

1

2

3

-

m

1

1 m

3

-

-

1,0

1,4

2,3

3,9

6,0

6,8

3

6

6

15

20

35

15

15

15

15

15

15

-

-

-

-

-

-

x

x

x

x

x

x

-

-

-

-

-

-

CSA

CSA

CSA

CSA

CSA

CSA

UL

UL

UL

UL

UL

UL

DIL EM

DIL EM

ZE-9

ZE-12

2

2

2

3

5

5

5

5

7,8

9,6

35

45

15

-

-

-

x

x

-

-

CSA

CSA

UL

UL

DIL 00 M

DIL 00 M

DIL 00 M

DIL 00 M

DIL 00 M

DIL 00 M

DIL 00 M

DIL 00 M

DIL 00 AM

Z 00-1

Z 00-1,6

Z 00-2,4

Z 00-4

Z 00-6

Z 00-10

Z 00-10

Z 00-16

Z 00-16

-

-

m

-

-

1 m

2

3

-

-

-

m

1

1 m

3

-

-

-

m

o

1

2

3

5

-

-

7 m

m

1

1 m

3

-

5

7 m

-

10

1,0

1,4

2,3

3,9

6,0

9,6

9,0

11

11

3

6

6

15

20

25

25

25

25

25

25

25

25

25

25

25

30

30

200

200

200

200

200

200

200

320

320

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

CSA

CSA

CSA

CSA

CSA

CSA

CSA

CSA

CSA

UL

UL

UL

UL

UL

UL

UL

UL

UL

DIL 0 M

DIL 0 M

DIL 0 AM

Z 00-16

Z 00-24

Z 00-24

-

5

-

5

7 m

-

10

-

15

-

15

20

15,2

22

22

25

60

60

30

30

30

320

320

320

x

x

x

x

x

x

CSA

CSA

CSA

UL

UL

UL

DIL 1 M

DIL 1 AM

DIL 1 AM

Z 1-40

Z 1-40

Z 1-57

10

-

-

10

-

15

20

25

-

25

30

-

32,2

34

42

125

125

200

125

125

150

1200

1200

2000

x

x

x

x

x

x

CSA

CSA

CSA

UL

UL

UL

3 phase, 60Hz, @:

Table 8b: Selection chart for North American „Contactors + Overload Relay“ combination

Maximum Short Circuit Protective device

for North America

Overload Relay Approvals

FusesNEC/CEC

Inverse Time CircuitBreakers NZM(H)...a

Possible Combinations

Contactor

max.O/L Relay

Rating data for combinations

Maximum Motor HP ratings

Max.

Motor-

Full

LoadCurrent(FLC )

1) CLASS J

2) CLASS L

AmpereRating

Max.

instantaneoustrip setting

Type

Type

200 V

HP

230 V

HP

460 V

HP

575 V

HP A A A A

Pluggedin

tocontactor

Separatelymounted

with Adapter EZ

KUseTerminalBlock

Canada USA

DIL2M

DIL2M

DIL2AM

DIL2AM

DIL2AM

Z 1-40

Z 1-57

Z 1-57

Z 1-63

Z 1-75

-

15

-

20

-

-

20

-

-

25

30

40

-

-

50

-

40

50

-

-

40

54

52

62,1

68

125

200

200

200

250

125

150

150

150

200

1200

2000

2000

2000

2400

x

x

x

x

-

x

x

x

x

x

CSA

CSA

CSA

CSA

CSA

UL

UL

UL

UL

UL

DIL3M80,

DIL3AM85

DIL3M80,

DIL3AM85

Z 5-70

Z 5-100

-

25

-

30

-

60

60

75

77

80

250

400 1)

250

400

2400

4800

x

x

x

x

CSA

CSA

UL

UL

DIL4M115,

DIL4AM145

DIL4M115,

DIL4AM145

DIL4M115,

DIL4AM145

Z 5-100

Z 5-125

Z 5-150

30

40

-

-

40

50

75

100

-

100

125

-

99

125

130

400 1)

400 1)

600 1)

400

500

600

4800

7200

7200

x

x

x

K

K

K

CSA

CSA

CSA

UL

UL

UL

DILM185

DILM225

DILM250

Z 5-160

Z 5-220

Z 5-250

50

60

75

60

75

100

125

150

200

150

200

250

156

192

248

600 1)

800 2)

700 2)

800

800

600

7200

16000

-

-

-

K

K

K

CSA

CSA

CSA

UL

UL

UL

DILM300

DILM400

DILM500

ZW 7-400

ZW 7-400

ZW 7-540

100

125

150

125

150

200

250

300

400

300

400

500

312

382

480

1000

1000

1000

1000

1000

600

-

-

-

-

-

-

K

K

K

CSA

CSA

CSA

UL

UL

UL

3 phase, 60Hz,@:

13



auxiliary contacts for switching controlcircuits. In North America, per current

product standards, the built-in and func-tionally active instantaneous magnetic trips are not recognized as elements that

provide the necessar y branch circuit overcurrent protective function.Manual motor starters are used primarilyas manually operated protective switchesin industrial control panels as well as indi-vidually enclosed starters for separatemotor loads. In North America they areselected primarily in accordance with themotor HP rating, whereas in Europe theselection process is done more in linewith respective current ranges as oppo-sed to assigned motor kW ratings. Thesesimply reflect local conventions. Regard-less of the method used, the end resultwill more or less be the same in bothcases.It is worth noting that, apart from mol-ded case circuit breakers, these manualmotor starters belong in a category oflow voltage equipment for which NorthAmerican and international approachesand viewpoints tend to be the furthestapart.From an international point of view,these devices represent compact andstand-alone manually operated motorprotective switches which offer all of thefollowing functional aspects:

• Main Disconnect and Isolator

characteristics• Short circuit protection• Overload protection• and across-the-line switching

capabilities

and, with the provision of certain keyaccessories, can also be applied as Emer-gency-OFF supply disconnect switches.Devices in the smaller adjustable currentranges are all short circuit proof and self-protective. Self-protective means that theirinner resistance (the bimetal trip assembly)is so great, that short circuit currents ashigh as 150,000 Amps will be so drastically

reduced as to enable the device, withoutthe need of any assistance from a back-upprotective switch, to protect itself andsafely handle the fault current without anydamage. These devices are well esta-blished globally and always offer the end-user an economically viable and attractivesolution. Their protective features havebeen verified so often, and in so many mil-lions of cases, that no one, other than inNorth America, has any doubts about theirworth and protective capabilities.From a North American perspective thisconstructionally identical motor protectiveswitch is simply categorized in its basic

form as a „manual motor controller“, andis thus not recognized as providing anyshort circuit protective features. All ofthese controllers, aside from those that

have undergone further evaluation asexplained later in the text, require a back-up overcurrent protective device in theirrespective branch circuit. (Diagram 4). Thisapplies equally in cases where the device isoperating in its self-protective range andeven when the device is additionally ULlisted and CSA certified in group installa-tions per local NEC and CEC electricalCodes. This rather demoted performancecapability is not the result of failed testingbut has more to do with the fact that,historically, North American standardshave required that the short circuit protec-tive feature be relegated to a separate setof overcurrent protective devices specifi-cally listed or certified for the purpose. Asthe following clarifications will showhowever, we have witnessed in the mean-time a rapprochement of the NA and IEC worlds in this respect.

Moeller Manual Motor Starters can beused globally. They are available in cur-rents ranging up to 42 A and offered invarious family versions (PKZM0, PKZ2/

ZM ). Approvals for the latest additionPKZM4 have not yet been completed andits ratings are thus mentioned only peri-pherally.

- Manual Motor Starters(Protectors) NZM

Motors, of course, come in larger sizes. Inthese ranges Moeller in North America canrely on a range of NZM type motor con-trollers for motor branch overload protec-tive functions. These are devices which canbe sold as circuit breakers internationally,but are approved in North America perUL 508 and CSA-C22.2 No. 14 as „Indus-trial Control Equipment“.

(„Manual Motor Starters NZM “ are onlyoffered for the North American market. Inthe international market place, manualmotor starters of the NZM variety are notcommon because the acronym NZM isalways synonymous with molded case cir-cuit breakers.)

These devices can be used in circuits withavailable faults as high as their respectiveshort circuit ratings, with the additionalcaveat that in the main incoming supplycircuit there is an available overcurrent

protective device which is listed and certi-fied for the purpose. This concept is moreor less the same and in line with the Groupinstallation regulations per UL 508, CSA-C22.2 No. 14. discussed earlier.

• Molded Case Circuit Breakers for theNorth American market

Molded case circuit breakers, as indicatedearlier in Table 3, belong to a grouping ofdevices falling under the umbrella of LowVoltage Energy Distribution Equipment(LVDE), and are designed and tested to

meet UL 489 und CSA-C22.2 No. 5-02safety standards for proper application perCode. These standards are amongst themost demanding and stringent of all com-ponent standards in North America. Oneof the main tasks of molded case circuitbreakers, as an alternative to fuses, is toprotect approved industrial control com-ponents (Industrial Control Equipment perUL 508 und CSA-C22.2 No.14), against thedestructive effects of short circuitcurrents.All compact circuit breakers with the acro-nym NZM mentioned herein are whatNorth Americans refer to locally as „Mol-

ded Case Circuit Breakers“ per UL andCSA.

14

Diagram 4: Manual Motor Controllers, built in accor-

dance to UL 508/CSA-C22.2 No. 14, e.g. PKZM0,

PKZ2/ZM .. and PKZM4, have to separately include

an overcurrent protective device in the motor branchcircuit per NEC/CEC regulations. Molded case circuit

breakers listed to UL 489 resp. CSA certified to C22.2

No. 5-02 can be used for this purpose, and are tested

with manual motor controllers accordingly.



- Instantaneous-only Circuit BreakersNZM...oBI-CNA (without bimetaltrips)

These devices feature adjustable magnetictrips for short circuit protection. They haveno bimetal trips and thus provide no over-load protective function. It’s possible incertain cases for these breakers to stillincorporate a bimetal element, but thiswould be done strictly to provide a betterdegree of internal self-protection and notbe mechanically linked in any way to theexternal tripping function. These breakersare rated per continuous nominal amperevalues. They can also be equipped withauxiliary contacts that generally featurePilot Duty control circuit load ratings.Unlike inverse time breakers, the UL/CSAapprovals do not permit an individualbreaking capacity rating to be marked onthese devices. The short circuit rating isrequired to be applied to the entire motorstarter assembly. That’s why, per UL stan-dards, these instantaneous-only circuitbreakers are recognized only, and notlisted. As such, these circuit breakers arenot sold individually but are usually combi-ned with a magnetic contactor and over-load relay to form a so-called „Combina-tion Motor Starter“ (Refer to next sectionfor more info on such starters.)In these starters, the contactor fulfillsacross-the-line motor switching duties, theoverload relay takes over the motor over-

load protective function and the circuitbreaker completes the picture by providingshort circuit protection as well as the maindisconnect and isolating function. Theseassemblies additionally make it possible,with the use of overload relay and circuitbreaker auxiliary contacts, to differentiatebetween overload and short circuit trip-ping indications. These types of combina-tion starters are also found in the IEC world, particularly in applications invol-ving long duration motor starting sequen-ces or for the very purpose just described,namely to provide signalling differentia-tion between overload and short circuit

tripping actions.In North America these starters are ofteninstalled as Motor Control Center (MCC )units or separately mounted in individualenclosures. They can be installed in circuitswith available faults as high as the com-plete „Combination Motor Starter“ shortcircuit rating without the need for anyadditional overcurrent protection device.The determining factor in the short circuitrating is always based on the weakestcomponent within the motor starter and isalways verified through testing. Additional„Back-up-Protection“ would be necessarywhenever the available fault would exceed

the short circuit rating of the starter. Perthe NEC , all combination motor startersfeaturing instantaneous circuit breakersmust be listed.(e.g. UL)

- Inverse Time Circuit BreakersNZM...(A)-NA

These are typical energy distribution brea-kers in North America but are also featuredprominently in Motor Control Centers andin industrial control panels. They are ratedin Amperes and are clearly marked withshort circuit interrupting capacities usuallyshown in kA. They can also be equippedwith auxiliary contacts that generally fea-ture Pilot Duty control circuit load ratings.These breakers feature an adjustable mag-netic or instantaneous response trip forshort circuit protection and either a fixedlong time response setting (Type suffix –A)or an adjustable overload range for theprotection of cables and other non-motorloads. However, they can still be utilized asthe main disconnect and short circuit pro-tective device of choice in motor circuits.Their auxiliary contacts are used to switchassociated control circuitry. They can beinstalled in circuits with available faults upto their maximum short circuit interruptingratings without the need for any additio-nal upstream overcurrent protection andcan also fulfill all Code requirements asMain Disconnect switches in service ent-rance and/or feeder circuit applications.

- Molded Case Circuit Breaker PKZ2..-CBThe PKZ2 family of products also featuresthe following components:

• PKZ2/ZM-16-CB,• PKZ2/ZM-25-CB and• PKZ2/ZM-32-8-CB

which are listed and certified in NorthAmerica as molded case circuit breakersper the UL 489 and CSA-C22.2 No. 5-02standards. They feature a short circuitinterrupting rating of 10 kA @ 240 VAC.Smaller ampere ranges are also planned inorder to cover AWG 16 and AWG 18 cablesizes, which have recently been formallyrecognized by the Codes as branch circuitconductors. UL is currently working out atest program to verify the suitability of

molded case breakers for this application.

- The advantages of molded casecircuit breakers over fuses in NorthAmerican motor branch circuits

A fuseless design, based on the properselection and application of circuit brea-kers and motor protective switches inmotor branch circuits, can provide the fol-lowing technical and economical advanta-ges over fuse based systems:

X Fuse bases for typical North Americanfuses are huge, and take up a lot of

valuable room inside industrial controlpanels.

X Molded Case Breakers like NZM undPKZ2/ZM-..-CB incorporate in one de-

vice the functions of main disconnectand isolation of the power circuit, shortcircuit and conductor overload protec-tion, and can still be more economicaland smaller in size than a correspon-ding combination of fuse base, fusesand fusible disconnect switch. Circuitbreakers interrupt all 3 poles simultane-ously in case of a fault, and they allowfor a much higher degree of continuityof service.

X Because of the many styles and charac-teristics of fuses in the US and Canada itis often very difficult for the non-Ameri-can machine or panel builder to esta-blish what type of fuse will work outbest for the end-user locally in terms ofavailability, especially in cases wherethe final location of the job site isunknown, or yet to be determined.

X The entire machine assembly and con-trol panel will be free and independentof any local fuse based issues and elimi-nate any problems arising from thelocation of spare parts.

• Manually operated disconnectswitches in motor circuits

A number of additional manually operatedcomponents from Moeller can be used inNorth American motor circuits, most nota-bly Type T rotary cam switches, motor cir-cuit disconnects Type P1 and P3 as well as

load break type N disconnect switches. Allof these devices have been listed and certi-fied per the North American industrial con-trol equipment UL 508 und CSA-C22.2No.14 standards and bear a marking tovalidate their further evaluation per Codeas motor circuit disconnect switches. Theyare usually required per Code to be instal-led on the load side of the final branch cir-cuit overcurrent protective device whichmakes them particularly suitable as indivi-dually enclosed lock-out/tag-out isolatorswitches local to the motor. They all fea-ture auxiliary contacts as accessories whichcan be used to switch associated control

cir cuitry.A new product, the P3-100-MCS , has alsobeen recently introduced by Moeller fordisconnect switch applications. This devicehas been constructionally enhanced withrespect to the more conventional P - or T -and competitive brand of switches in itssphere of application. The switch now fea-tures the large creepage and clearancespacings of conventional distributionequipment and has been successfully listedper the UL 489 standard as a full fledgedMolded Case Switch. As such, the productcan be installed without limitations perCode as a line side Main Disconnect switch

in motor circuits per Part J / Part IX (seeDiagram 1.)

15



Motor Starters in accordance

with North American

specifications

Table 9 provides basic clarifications of themost commonly used terms and expressionsused in association with various motor star-ter solutions. The concept of Non-combina-tion Motor Starters was already introduced

on page 12. Table 10 compares a widerange of the most popular, as well as lesserknown motor starter solutions used throug-hout the IEC -world and North America.

16

Standards terminology: Motor Controller

Generally speaking „Motor Con-troller “ refers to the followingconcept in North America:

All power components and assemblies that are used for switching electrical motorsON and OFF, and which may or may not include additional protective functions.

Significance: Controller is the official term used in the NEC , and since UL-standards are based on the NEC , this

is the term most commonly used throughout UL-standards to denote individual motor switching

components and assemblies evaluated for that purpose.

Some examples within the

Moeller family of components andassemblies:

1. Contactors DIL M , without protective function,

2. Motor starter combinations DIL / Z with overload protective function,3. Manually operated P und T switches, without protective function,,4. Manual Motor Starter PKZM0 with overload protective function,

5. Manual self-protected combination starter PKZM0-../SP (Type E-Starter)

with overload and short circuit protective functions

Market terminology: Motor Starter

Generally speaking, a „Motor Starter “ refers to the following con-cept in North America:

Individual or group of „Motor Controller“ components which additionally featurea protective function.

Significance:

Some examples within theMoeller family of componentsand assemblies:

1. Motor protective switches PKZM und PKZ (manual motor starter)

2. Remotely operated motor starter combination DIL / Z , (Non-combination Motor starter)

3. Manual or remotely operated motor starter combination NZM / DIL / Z , (Combination Motor

starter)

Further differentiation within Motor Starter groupings

without Contactor with Contactor

Non-Combination Motor Starter Combination Motor Starter 1 ) or

Combination Motor Controller

2)

1 ) + 2) identical terms: Industryterminology1), UL 508 terminology 2)

• No isolation (Main Disconnect),

• No short circuit protection,

Both these functions need to beseparately provided.

fulfills all 4 motor branch circuit functions

per NEC Diagram 430-1:

• Isolation (Main Disconnect),

• Motor switching (Controller),• Short circuit protection,

• Overload protection

Examples within the Moellerfamily of components and

assemblies:

PKZ2/ZM + DIL M PKZM0-../SP 3) + DILM

(Type F-Combination Starter)3) Manual Self-protected Combination Controller

Table 9: Clarifications on commonly used terms „Motor Controller“, „Motor Starter“, „Combination Motor Controller“, „Combination Motor Starter“ and

„Non-Combination Motor Starter“

The industry in North America refers to this term much more commonly when denoting motor controllerswith protective functions.



Table 10: Differences between typical North American and IEC motor starter assemblies.

North America IEC-World

R e m o t e l y ( m a g n e t i c a l l y ) o p e

r a t e d

P2-.../F-...-CNA

+ Class H, R or JFuses

+ DILM + Z

„combination motor

starter“

• Fusible Type

• Self-Protected Type

• Inverse Time CircuitBreaker Type

• Instantaneous CircuitBreaker Type

• Fusible Type

• Fuse+ Contactor+ Overload relay

M o t o r s t a r t e r

F u s e

b a s e d

m o t o r s t a r t e r s

PKZ2/ZM-.../S-SP • Motor protective switch+ Contactor

F u s e l e s s m o t o r s t a r t e r

s

NZM7-..-NA

+DILM • Circuit Breaker

+ Contactor

NZM6B/ZM6A-NA

+DILM

+Z

• Circuit Breaker+ Contactor+ Overload relay

• Motor protective switch(without overload function)+ Contactor+ Overload relay

NZM...oBI-CNA+DILM

+Z

• Circuit Breaker (withoutoverload function)+ Contactor+ Overload relay

≤ 2 HP and 300 V:P1

+ Class CC or JFuses

+ DILM

+ Z

• Fuse+ Cam switch+ Contactor+ Overload relay

F u s e b a s e d

m o t o r s t a r t e r s

M a n u a l l y o p e r a t e d

PKZM0

PKZ2/ZM -..„manual motor controller“ • Motor protective switch

F u s e l e s s m o t o r s t a r t e r

s

NZM7-..-NA

additionally evaluated toUL 508

• Circuit breaker with

Legend:

= commonly used

= less conventional

17



• Combination Motor Starters

A motor starter of European origin, whichincludes all the necessary components tofulfill motor short circuit and overload pro-tective functions, as well as motor switchingduties (e.g. Circuit breaker + Contactor +Overload relay) is referred to in the US andCanada as a “Combination Motor Starter ”.Apart from Type E self-protected combina-tion starters (explained in the upcoming sec-tion) these starters are by definition consi-dered to be individually enclosed assembliesin North America, which is again a departurefrom traditional European definitions. Likesmall control panels they should be more orless engineered to include all the necessaryparts and pieces to complete a stand alonemotor starter assembly. The selection of con-tactors and overload relays follows the sameprocess as shown in Tables 8a and 8b.

Various constructive solutions for

„Combination Motor Starters“

The fundamental principles guiding the NorthAmerican perspective on motor starters werehighlighted and defined earlier in Diagram 1.Diagram 1 also points to a fundamental dif-ference from the international viewpoint, notreadily apparent in the diagram, that compo-nents fulfilling Parts IX „Main Disconnect“und IV „Short circuit protection“ were histori-cally provided for separately in the motorbranch circuit (refer to Diagram 4). In ensuingyears, conventions changed and progressopened the door for more global and techno-logically diverse solutions to emerge and esta-blish themselves. Table 11 shows the series ofdevelopments in this respect. Various combi-nation starter solutions currently available andin compliance with NEC/CEC motor branchcircuit guidelines (Diagram 1) are alphabeti-cally tagged as a function of their construction(Types A…F at this time).

• Type E Self-ProtectedCombination Motor Controller

A significant step in the expansion of UL508 [9] and CSA-C22.2 No. 14 [10] withrespect to combination motor controllerscame about with the introduction of “Con-struction Type E” in each respective stan-dard. In order to fulfill the necessaryupstream main disconnect and short circuitprotective functions which are inherent ele-ments of every combination starter, thesecomponents needed to feature a high shortcircuit rating as well as large electrical clea-rances on their incoming supply side fieldwiring terminals in accordance with UL 489[7] and CSA-C22.2 No. 5-02 [8] specifica-tions. (Diagram 5). It is worth noting that allcurrently available self-protected „Type E “-Starters have only been listed and certifiedfor use in solidly grounded 4 wire, wye-typesupply networks (e.g. 480Y/277 VAC or600Y/347 VAC).

18

Constructive solutions „UL 508-Combination Motor Starters“

Configuration Part IX resp. Part J Part IV resp. Part D Part VII resp. Part G Part III resp. Part C

Construction Type Main Disconnect Branch Circuit Short

Circuit Protection

Motor Controller Motor Overload

A Individual devicelisted to UL 98 / 489

Listed fuses perUL 248 series

Individual deviceper UL 508


Molded Case Switch e.g.:P3-100-MCS orNZM 7-..-NA

Class J or RK5 Ex: + DIL M Ex: + Z, + PKZM 0

B per UL 98 / 489 Motor Circuit Protector Individual device perUL 508 Ex: + DIL M

Individual device perUL 508 Ex: + Z, + PKZM 0

C Inverse Time Breakerper UL 489



Ex: NZM7-..-NA Ex: + DIL 4M115 In this case: NZM7-..-NA

• By virtue of additionalcalibration tests perUL 508

D Instantaneous-only Breaker

per UL 489

Individual device

per UL 508

Individual device

per UL 508

Ex: NZM10-..-OBi-CNA Ex.: + DIL M Ex: + Z

E Self-Protected Combination Motor Controller

Ex.: PKZ2-ZM-.. /S-SP

F Manual Self-Protected Combination MotorController, Manual Type-E-starter


Ex: PKZM0-.../SP Ex: + DIL M

Table 11: Various solutions of „UL 508 - Combination Motor Starters“, alphabetically identified in the standard by construction types „A“ through „F“.

Construction Types E und F are particularly interesting in view of this paper’s focus on European style Manual Motor Protective switches.

Note that Types „A“ through „E“ are also currently described in the analog CSA-C22.2 No. 14 standard.



The use of Self-protected Type E-Combina-tion Starters provides numerous benefits:

X Simplified engineering, no need tocoordinate with a back-up overcurrentprotective device (often unknown) dueto its stand-alone rating.

X The amount of necessary layout space isgreatly reduced.

X No assembly and wiring requiredbetween individually mounted startercomponents.

X Lower component costs

X Lower panel wiring and assemblycharges

X A design more in line with currenttechnological control panel advancesused throughout the IEC -world.

- Self-Protected Combination StarterPKZ2/ZM-.../S-SP

The Self-Protected Combination StarterType PKZ2/ZM-.../S-SP (Diagram 6) fulfillsall „Type E “-requirements. This high faultrated compact combination starter ismade up of a thermal-magnetic manualmotor protective switch PKZ2/ZM-.. and ahigh fault capacity magnetic controller

(contactor) /S . The unit features a built-inshort circuit trip indicator. Following ashort circuit interruption and after thesource of the fault has been cleared, thedevice remains fully calibrated and can beimmediately brought back in line to pro-vide „Continuity of service“ performance.The manual motor protective portionPKZ2/ZM-… features the large electrical

clearances on its incoming supply side fieldwiring terminals in accordance with UL489. An important element in fulfillingType E requirements for high fault ratingsis the high capacity magnetic contactorwhich features current limiting contactsand a customized internal magnetic trip toprovide the starter’s high level fault inter-rupting capability. This special contactor is

Diagram 6: The above diagram shows that the essential requirements of the motor branch circuit outlined in NEC Diagram 430-1 are fulfilled by the construc-

tive elements of the UL listed and CSA certified PKZ2/ZM-.../S-SP Self-protected Combination Motor Controller. Both The PKZ 2’s disconect(Part IX)

and contactor (Part VII) modules each feature a set of current limiting contacts which provide the starter with its high capacity and high fault

rating performance capability. The device can also be used world-wide.

alt/neu

Part B430-24430-25, 430-26Motor feeder

Motor feedershort-circuit andground-fault protection Part E

Motor disconnecting means Part J

Motor branch-circuitshort-circuit andground-fault protection Part D

Motor circuit conductor Part BMotor controller Part G

Motor control circuits Part F

Motor overload protection Part C

Part C

Motor Part A

Thermal protection

Secondary controllerSecondary conductors

Part B430-23

Secondary resistor

Part B

430-23 and Article 470

To Supply

/II

/V

/IX

/IV

/II/VII

/VI

/III

/I

/III

/II

/II

IX

IV

III

VII

PKZ 2/ZM-.../S-SP

NEC Article 430, Diagram 430-1

19

Diagram 5: UL / CSA „Type E“ - Combination starters fulfill all 4 functions required in the motor branch

circuit. The back-up protective switch can be eliminated. „Type E “- starters are referred to

as Self-protected .

UL 508 „Type E“

„Type E “-Devices fulfill all 4

functions (Main Disconnect,

Short Circuit, Overload,Controller).

The Back-up protective

switch can be eliminated.

Back-up protectiveswitch



a vital part of the assembly and providesthe additional current limitation capabi-lity necessary to achieve self-protection.The starter is suitable for 600 VAC solidlygrounded wye supply systems (600Y/ 347 V) for motor full load currents up to27A (25HP at 575 V) and 480Y/277 VAC circuits for motor FLCs up to 42 A (15/30HP at 230/460 V).The PKZ2/ZM-.../S-SP’s stand alone shortcircuit rating is 65 kA / 480 V and 42 kA / 600 V. The compact starter’s main designfeatures include:X A plug-in, adjustable thermal-magnetic

trip module in line with North Americanmotor full load current ratings and ahigh capacity, high fault current limi-ting contactor for motor switching pur-poses which is countoured to fit directlyinto the protective switch portion.

All system component modules, e.g. auxi-liary contacts, voltage trips and remote con-trol drive are UL listed and CSA certifiedaccessories which can be field installed. Thestarter also features control circuit tap-offsbetween the disconnect and the contactor.That is especially useful in tight, limitedspace applications like Motor Control Cen-ter (MCC ) starter units which incorporatecontrol transformers to supply the starter’s

control circuit loads and circuitry. (Diagram7). All of these features contribute to makethe PKZ 2 a truly innovative and high perfor-mance combination motor starter.

- Manual Self-Protected Combination

Starter PKZM0-../SP Even the smaller sized Manual Motor star-ter PKZM0 fulfills the stringent „Type E“ -requirements in a special version TypePKZM0-../SP , and in that form is a full fled-ged stand-alone device which does notrequire any additional back-up overcurrentprotection. This version is offered in a cur-rent range up to 25 A. The PKZM0-../SP differentiates itself from the „normal“ IEC -World PKZM0 because of the large electri-cal creepage and clearance distances on itsincoming supply side field wiring terminals(Photo 8).

The requirements in North America are notalways regionally identical:

- For applications in the USThe large electrical clearances are requiredon the device’s incoming supply side fieldwiring terminals. When „open“ mountingthe starter (i.e. on a mounting plate in acontrol panel equipped with a larger pad-lockable main disconnect switch) eachindividual device i s not required to featurea padlockable handle.On the other hand, if the starter in its self-protected version is individually enclosed

(e.g. in a Motor Control Center unit or aseparate CI-..-K-NA insulating materialenclosure) a padlocking feature is requi-red . That’s because, as an individually

enclosed Combination Motor Starter, the

switch assumes the Main Disconnect andIsolator functions and must thus be pad-lockable in the OFF position.

- For applications in CanadaFor the Canadian market, the PKZM0-..(/SP), as a manual self-protected combi-nation starter per CLASS 321108, mustgenerally always be equipped with the

padlockable knob AK-PKZ0 for manualoperation. The larger clearances requiredin the US on the switch’s supply side termi-nals are (as of this writing) not necessary,however, they are certainly acceptable

when provided. In Canada, therefore,there is presently a choice of using eitherthe Type E PKZM0-../SP with the largerclearances, or any of the normal PKZM0marked as Type E, as stand-alone deviceswithout the need for any back-up protec-tion, as long as it is equipped with the pad-lockable knob accessory.

• Manual Motor ControllersPKZM0 with special supply terminalBK25-..-E

The PKZM0 has successfully passed all theadditional Tap Conductor Protector verifica-tion tests (see page 23). This approval statushas made it possible to provide an additio-

20

Diagram 7: Control circuit tap-offs on the

PKZ2-ZM../S-SP for transformer feed

in a Motor Control Center starter

application.

Photo 8: The photo shows the constructive differences: left: „normal“ manual motor controller

PKZM0, right: Manual Self-Protected combination Starter PKZM0-../SP with the larger

electrical clearances on its incoming supply terminals.



Moeller bus feeder connectors and wiringaccessories are UL listed and CSA certifiedfor the purpose.

Photo 9: A group of manual motor controllers PKZM0 additionally evaluated as Tap Conductor Protectors share a common terminal supply block BK25...-E

and are fed via a feeder bus connector. The incoming terminal’s large electrical clearances enable the entire assembly to meet self-protected

„Construction Type E” requirements.

Diagram 10: „Type F Combination Motor Starters“ fulfill all 4 functions of a combination motor starter

per UL 508 . The back-up protective switch can be eliminated.

nal, and very innovative, method of creatinga Type E starter or starter groupings withinthe PKZM0 system of modular wiring andmounting accessories. By using specializedPKZM0 wiring accessories, primarily thecommonly used 3 phase bus connectorblock and combining it with a special inco-ming supply terminal, it’s possible to trans-form a normal tap conductor protectorPKZM0 into an individual Type E starter or

grouping of Type E starters. This customincoming supply terminal BK25...-E (Photo9) must incorporate large distribution clea-rances per UL 489. In addition, all possibleconfigurations are tested to maintain andverify their approval status.

This use of modern wiring techniques is verymuch in line with the IEC method of effi-ciently feeding a large number of manualstarters for outgoing circuits and neatlygrouping them together in the most spaceconscious, cost saving manner. It thus re-presents an ideal way to provide modern,IEC style industrial control panels for North

American applications and maintain fullcompliance with local NEC/CEC Code requi-rements.

21

The only true difference lies in the large spa-cing incoming supply terminal block, whichis mandated by the Type E regulations. All

UL 508 „Type F“

„Type F “-Starters consist of

a Manual „Type E “- Starterand a magnetic contactor.

The back-up protective

switch can be eliminated.

Back-up protectiveswitch

1 = (Manual) „Type E “-Starter2 = Magnetic contactor



• Type F Combination Starter

UL has now officially introduced in the UL508 standard the latest category of combi-nation motor starters: a “Type F Combina-tion Motor Controller”. A Type F combina-tion controller consists simply of a Manualself-protected „Type E “ combination motorcontroller (e.g. a PKZM0-../SP , or a PKZM0-..equipped with the large clearance terminalblock Type BK25-..-E ) combined with a stan-dard magnetic contactor (controller). As perDiagram 10 „Type F Combination MotorStarters“ also eliminate the need for a back-up overcurrent protective device. All suchcombinations must be submitted by themanufacturer for UL listing and CSA certifi-cation. (Table 12) (Photo 11). Moelleralready has in submittal to UL a number ofType F combination starters covering a widerange of HP ratings. It is also worth notingthat all currently available „Type F“-Starters,like „Type E“-Starters, are only suitable forsolidly grounded 4 wire, wye-type supplynetworks (e.g. 480Y/277 V). „Type F“- com-bination Starters are only possible in the USat this time, because the CSA standard hasnot yet officially adopted it.

A straight-forward modular assembly set-upsystem, in which the manufacturer or theindependent panel builder can put togetherUL listed and CSA certified components andself-certify or label the resulting starter orassembly, does not exist as such in North

America. It is possible, however, to have a ULlisted or CSA certified panel shop andassemble combinations that are covered bya procedure or file. It is strongly recommen-ded, therefore, for such an assembly work-shop or panel builder in the market to buildor engineer similar combinations andassemblies, to work closely with the manu-facturer for the latest approval updates andcomponent rating information, since thereare always ongoing design improvementsbeing developed which could represent sig-nificant technological and economicaladvantages to their business.

It is generally acknowledged that the appro-val process can be both a time and costintensive endeavor which can often undulydelay the introduction of new products andtechnology into the market place. This notonly puts the component manufacturer at adisadvantage but can also be detrimental tothe panel builder and end-user, since theintroduction of certain design innovationscould translate into significant improve-ments for their business. Because of the veryhigh export quota of European machineryand panel builders it is also neither practicalnor feasible for a manufacturer to introduceand establish new products and technolo-

gies that have not yet been approved perNorth American standards, even when a sig-nificant portion of this equipment is desti-ned for the domestic EU market and would

22

Photo 11: Example of a Type F combination motor starter, built up from the combination of a manual

Type E starter and a set of magnetic contactors.

Table 12: UL listed „Type F Combination starters“ with their respective ratings

Manual MotorStarter

Version /SP or with

BK25-E terminal

block

Contactor Nominal voltage Short Circuit rating

PKZM0 up to 11 A DILEM -.. 600Y / 347 V AC 50 kA

PKZM0 up to 11 A DIL00M -.. 600Y / 347 V AC 50 kA

PKZM0 up to 11 A SE00-..-PKZ0 600Y / 347 V AC 18 kA

PKZM0 up to 11 APKZM0 16 APKZM0 20 + 25 A

DIL0M -.. 480Y / 277 V AC 50 kA42 kA18 kA



remain in Europe. The approval process alsopractically rules out customized assemblydesigns that would combine products fromdifferent manufacturers. These mixed com-binations are also not usual in the IEC worldbecause the manufacturer is solely able toverify the electrical coordination and perfor-mance of components of his own make, par-ticularly with respect to short circuit testingand determination of proper overcurrentcoordination performance levels. The Euro-pean „Declarations of Conformity“ must, bydefinition, also be current because they areessentially verifying to the user that a parti-cular combination of products and assem-blies reflects actual ongoing productionquality levels which were in place at the timethe “Declaration of Conformity” was issued.Practically speaking, manufacturers whichwould combine products of different makesto produce starters and assemblies wouldnot be able to keep up with ongoing chan-ges in competitive products, which could besignificant in view of the consequences itmay have on short circuit coordinationvalues and component performance levels.

Tap Conductor Protector

A new alternative to the use of stand-alonemanual Type E combination starters is the„Tap Conductor Protector“. It’s not neces-sary for that particular device to feature the

large distribution clearances on its incomingsupply terminals like the UL 508 standardrequires it for the Type E devices. A „nor-

mal“ Manual Motor Starter PKZM0 can beused for the purpose, as long as it has passedthe necessary approval tests and is appropri-ately marked for the application. ThePKZM0 has been successfully evaluated byUL and is listed as a Tap Conductor Protectorup to its full rating of 25 A for solidly groun-ded 480Y/277 VAC supply systems. It’s alsolisted up to 11 A for that application in600Y/ 347 V circuits.

Tap Conductor Protectors like the PKZM0provide overload and short circuit protec-tion for outgoing motor circuit conductors,as well as overload protection for the motor.The drawback is, however, that the use of atap conductor protector does not eliminatethe need for back-up branch circuit overcur-rent protection as depicted in Diagram 1.However, that’s really not so much of adisadvantage when one considers that thesedevices are mostly used in larger industrialcontrol panels which feature a back-updisconnect switch in any case.

The use of Tap Conductor Protectors meansthat, as shown in Diagram 12, the ratio bet-ween the rating of the Back-up protectiveswitch and the ampacity of the outgoingmotor circuit conductors cannot exceed10:1. Example:

• The ampacity of an AWG 14- conductoris 20 A,

• The back-up switch could be the

200 A rated NZM9/ZM9A-200-NAUL listed/ CSA certified molded casecircuit breaker.

Documentation:

[1] IEC / EN 60947-4-1 and DIN VDE 0660-102 „Low-voltage switch-gear and controlgear Part4-1:Electromechanical contactorsand motor-starters“

[2] UL 60 947 , „Proposed FirstEdition of the Standard forLow Voltage Switchgear and

Controlgear“[3] IEC / EN 60 204-1 and

DIN EN 60204-1,„Electrical equipment ofindustrial machines“

[4] IEC / EN 60 947-1,„Low-voltage switchgear andcontrolgear Part 1: General Rules“

[5] IEC / EN 60 947-2,„Low-voltage switchgear andcontrolgear Part 2:Circuit-breakers“

[6] IEC / EN 60 947-3, „Low-voltage

switchgear and controlgear Part 3:Switches, disconnectors,switch-disconnectors andfuse-combination units“

[7] UL 489, „Molded Case CircuitBreakers, Molded Case Switchesand Circuit Breaker Enclosures“

[8] CSA-C22.2 No. 5-02, „MouldedCase Circuit Breakers

[9] UL 508, „Industrial ControlEquipment”

[10] CSA-C22.2 No. 14, „Industrial

Control Equipment, IndustrialProducts”

23

Diagram 12: Maximum ratio between the rated current of the Back-up protective switch and the am-

pacity of the outgoing motor circuit conductors when using “Tap Conductor Protectors”.

Summary in Diagram 13

Diagram 13 is a graphical representation ofall the major concepts presented in thispaper, and dwells in particular on the impor-tant aspects of motor starter ConstructionTypes E, F and the Tap Conductor Protector.When using this Solution Processing Chartit’s important to determine if a back-upovercurrent protective device is already pro-vided in the circuit, or, if it is feasible to pur-sue a more IEC -like solution that better relieson the enhanced performance capabilitiesof the starter components involved and eli-minates the need for additional back-upprotection.

Validity:

This paper reflects the standards situationand approval status in effect as of March2003.

(PKZ)

„Tap Conductor Protector “

Ratio of Back-up device

current rating and ampacity

of outgoing motor circuit

conductors 10:1

Back-up protective

device



M

N o r t h A m e r i c a n

M o t o r S t a r t e r s i n a c c o r d a n c e w i t h U

L 5 0 8 a n d C S A - C 2 2 . 2

N o .

1 4

S o l u t i o n P r o c e s s i n g

C h a r t , S e a r c h c r i t e r i a : f a v o r i n g f u s e l e s s i n s t a l l a t i o n s i n a c c o r d a n c e w i t h l o c a l N

o r t h A m e r i c a n E l e c t r i c a l C o d e s , w h e n e v

e r p o s s i b l e i n l i n e w i t h I E C s o l u t i o n s .

M a i n D i s c o n n e c t a n d B r a n c h C i r c u i t

S h o r t C i r c u i t p r o t e c t i v e f u n c t i o n s

p e r U L 4 8 9

a n d C S A - C 2 2 . 2

N o .

5 - 0 2

a r e i n

t h e s u p p l y c i r c u i t o r

o t h e r w i s e s e p a r a t e l y p r o v i d e d

M a i n D

i s c o n n e c t a n d B r a n c h C i r c u i t

S h o r t

C i r c u i t p r o t e c t i v e f u n c t i o n s

p e r U L

4 8 9 a n d C S A - C 2 2 . 2

N o .

5 - 0 2

a r e n o t

i n t h e s u p p l y c i r c u i t a n d n o t

k n o w n o r

o t h e r w i s e s e p a r a t e l y p r o v i d e d

T a p C o n d u c t o r P r o t e

c t o r

U s e o f L i s t e d / C e r t i f i e d

C o m p o n e n t s

p e r N E C / U L 5 0 8

U S A o n l y

p e r U L 5 0 8 a n d

C S A - C 2 2 . 2 N o . 1 4

f o r M o t o r C o n t r o l l e r

s w i t c h i n g f u n c t i o n s

f o r M o t o r O v e r l o a d p r o t e c t i o n

N o t t h e m a i n t h e m e o f t h i s

t e c h n i c a l p a p e r . S h o w n h e r e

f o r c o m p l e t e n e s s p u r p o s e s o n l y .

P r o t e c t i o n w i t h

F u s e s

( s h o r t c i r c u i t r a t i n g s m a y v a r y )

C o n s t r u c t i o n T y p e " A "

C o n s t r u

c t i o n T y p e " B "

C o n s t r u c t i o n T y p

e " C "

C o n s t r u c t i o n T y p e " D "

R e f e r t o T a b l e 1 1 f o r

e x a m p l e s o f M o e l l e r

o f f e r i n g s i n t h i s c a t e g o r y .







C u r r e n t l y n o M o e l l e r

o f f e r i n g .

T h e a b o v e T y p e s a r e n o t t h e m a i n f o c

u s o f t h i s t e c h n i c a l p a p e r a n d a r e s h o w n h e r e f o r c o m p l e t e n e s s p u r p o s e s o n l y .

R e q u i r e m e n t s :

- H i g h S h o r t C i r c u i t r a t i n g s

- L a r g e r e l e c t r i c a l c l e a r a n c e s o n

t h e c o m p o n e n t i n c o m i n g

s u p p l y s i d e .

P e r U L 5 0 8 a n d

C S A - C 2 2 . 2 N o . 1 4



R e m o t e l y ( e l e c t r o - m a g n e t i c a l l y ) o p e r a t e d

T a p C o n d u c t o r P r o t e c

t o r

S e l f - P r o t e c t e d S t a r t e r

M a n u a l S e l f - P r o t e c t e d S t a r t e r

P K Z M 0

H i g h F a u l t r a t e d , c o m p a c t

C o m b i n a t i o n M o t o r

S t a r t e r

P K Z 2 / Z M - . . . / S - S P

P K Z M 0

+ 3 P h a s e B u s C o n n e c t o r

+ I n c o m i n g s u p p l y T e r m i n a l

B K 2 5 - . . - E

P K Z M 0 - . . . / S P

f o r M o t o r C o n t r o l l e r

s w i t c h i n g f u n c t i o n s

f o r M o t o r O v e r l o a d p r o t e c t i o n

C o m b i n a t i o n M o t o r S t a r t e r s

p e r U L 5 0 8 a n d

C S A - C 2 2 . 2 N o . 1

4

F u l f i l l a l l 4 m a i n f u n c t i o n s

i n t h e N o r t h A m e

r i c a n

m o t o r b r a n c h c i r c u i t :

M o t o r C o n t r o l l e r

M o t o r O v e r l o a d

P r o t e c t i o n

S h o r t C i r c u i t P r o t e c t i o n

M a i n D i s c o n n e c t

F u s e l e s s P r o t e c t i o n

C o n s t r u c t i o n T y p e " E "

T y

p e " E " S e l f - P r o t e c t e d C o m b i n a t i o n M o t o r S t a r t e r s



M

M

M

M

M

M

M

M

A C - R a t e d V o l t a g e :

u p t o 2 7 A :

6 0 0 Y / 3 4 7 V

>

2 7 A :

4 8 0 Y / 2 7 7 V

S h o r t C i r c u i t R a t i n g :

6 5 k A / 4 8 0 Y / 2 7 7 V

4 2 k A / 6 0 0 Y / 3 4 7 V

A C - R a t e d V o l t a g e a s p e r

t h e s h o r t c i r c u i t r a t i n g :

u p t o 1 1 A : 5 0 k A / 6 0 0 Y / 3 4 7

V

1 6 A :

4 2 k A / 4 8 0 Y / 2 7 7

V

2 0 . . 2 5 A :

1 8 k A / 4 8 0 Y / 2 7 7

V

C u r r e n t R a n g e s u p t o 2 5 A

A C - R a t e d V o l t a g e a

s p e r


u p t o 1 1 A : 5 0 k A / 4 8 0 Y / 2 7 7 V

1 6 A :

4 2 k A / 4 8 0 Y / 2 7 7 V

2 0 . . 2 5 A :

1 8 k A / 4 8 0 Y / 2 7 7 V

C u r r e n t R a

n g e s u p t o 1 1 A

A C - R a t e d

V o l t a g e a s p e r


1 8 k A / 6 0 0 Y / 3 4 7 V




5 0 k A / 6 0 0 Y / 3 4 7 V



u p t o 1 1 A : 5 0 k A / 6 0 0

Y / 3 4 7 V

1 6 A :

4 2 k A / 4 8 0

Y / 2 7 7 V

2 0 . . 2 5 A :

1 8 k A / 4 8 0

Y / 2 7 7 V



u p t o 1 1 A : 5 0 k A / 6 0 0 Y / 3 4 7 V

1 6 A :

4 2 k A / 4 8 0 Y / 2 7 7 V

2 0 . . 2 5 A :

1 8 k A / 4 8 0 Y / 2 7 7 V

F o r g r o u n d e d s u p p l y n e t w o r k

s

F o r g r o u n d e d s u p p l y n e

t w o r k s

I f t h e S h o r t C i r c u i t r a t i n g i s i n s u f f i c i e n t o r o t h e r w i s e u n s u i t a b l e :

R e f e r t o L i s t e d / C e r t i f i e d r a t i n g s f o r G r o u p i n s t a l l a t i o n s , p e r T a b l e 5

C o n d u c t o r p r o t e c t i o n s u b j e c t t o t h e 1 / 3 R u l e

, p e r d i a g r a m 3

I f t h e S h o r t C i r c u i t r a t i n g i s i n s u f f i c i e n t o r

o t h e r w i s e u n s u i t a b l e :

R e f e r t o L i s t e d / C e r t i f i e d r a t i n g s f o r G r o u p i n

s t a l l a t i o n s , p e r T a b l e 5

C o n d u c t o r p r o t e c t i o n s u b j e c t t o t h e 1 / 3

R u l e , p e r d i a g r a m 3

L i s t e d f o r T a p C o n d u c t o

r

P r o t e c t i o n , s u b j e c t t o t h

e

1 / 1 0 t h R u l e , p e r d i a g r a

m 1

1

T y p e " F " C o m b i n a t i o n M o t o r S t a r t e r s

L i s t e d p e r U L 5 0 8

( U S A o n l y a t t h i s t i m e )

+ D I L E M

+ D I L 0 0 M

+ S E 0 0 - P

K Z 0

+ D I L 0 M

F o r g r o u n d e d s u p p l y n e t

w o r k s

P K Z M 0

+ 3 P h a s e

B u s C o n n e c t o r

+ I n c o m i n

g s u p p l y

T e r m i n a

l B K 2 5 - . . - E

+ M a g n e t

i c C o n t r o l l e r ( C o n t a c t o r )

P K Z M 0 - . . . / S P

+ M a g n e t i c C o n t r o l l e r

( C o n t a c t o r )




5 0 k A / 6 0 0 Y / 3 4 7 V

R e m o t e l y ( e l e c t r o - m a g n e t i c a l l y ) o p e r a t e d

B i l d 1 3



26

Table 310-16. Allowable Ampacities of Insulated Conductors Rated0 through 2000 Volts, 60 to 90C (140 to 194F)

Not More Than Three Current-Carrying Conductors in Raceway or Cable or Earth (Directly Buried), Based on Ambient Temperature of 30C (86F)

Size Temperature Rating of Conductor. See Table 310-13 Size

1816141210864321

1/02/03/04/0250300350400500600700750800900

10001250150017502000

60C 75C 90C 60C 75C 90C (140F) (167F) (194F) (140F) (167F) (194F)

TypesTWA,UFA

TypesFEPWA,

RHA, RHWATHHWA,THWA,

THWNA,XHHWA

USEA, ZWA

TypesTBS, SA

SIS, FEPA,FEPBA, MI

RHHA, RHW-2,THHNA,THHWA,THW-2A,THWN-2A

USE-2, XHH,XHHWA

XHHW-2,ZW-2

TypesTWA,UFA

TypesRHA, RHWA

THHWA,THWA,

THWNA,XHHWAUSEA

TypesTBS,

SA, SIS,THHNA,THHWA,THW-2A,THWN-2A

RHHARHW-2,USE-2,

XHH, XHHW,

XHHW-2,ZW-2

AWGkcmil

AWGkcmil

Copper Aluminum or Copper-Clad Aluminum

........20A25A304055708595110125145165195215240260280320355385400410435455495520545560

........20A25A35A506585

100115130150175200230255285310335380420460475490520545590625650665

141825A30A40A557595110130150170195225260290320350380430475520535555585615665705735750

........

....20A25304055657585100115130150170190210225260285310320330355375405435455470

........

....20A30A4050657590100120135155180205230250270310340375385395425445485520545560

........

....25A35A45607085100115135150175205230255280305350385420435450480500545585615630

........

....1210864321

1/02/03/04/025030035040050060070075080090010001250150017502000

CORRECTION FACTORS

AmbientTempC

For ambient temperatures other than 30C (86F), multiply the allowable ampacitiesshown above by the appropriate factor shown below.

AmbientTempF

21-2526-3031-3536-4041-4546-5051-5556-6061-70

71-80

1.081.00.91.82.71.58.41........

....

1.051.00.94.88.82.75.67.58.33

....

1.041.00.96.91.87.82.76.71.58

.41

1.081.00.91.82.71.58.41........

....

1.051.00.94.88.82.75.67.58.33

....

1.041.00.96.91.87.82.76.71.58

.41

70-7778-8687-9596-104105-113114-122123-131132-140141-158

159-176 AUnless otherwise specifically permitted elsewhere in this code , the overcurrent protection for conductor types

marked with an obelisk (A) shall not exceed 15 amperes for No. 14, 20 amperes for No. 12, and 30 amperes for

No. 10 copper; or 15 amperes for No. 12 and 25 amperes for No. 10 aluminum and copper-clad aluminum after

any correction factors for ambient t emperature and number of conductors have been applied.

Table 430-91. Motor Controller Enclosure Selection Table

For Outdoor UseProvides a Degree of Protection

Against the FollowingEnvironmental Conditions

Enclosure Type Number A

3 3R 3S 4 4X 6 6P

Incidental contact with the enclosed equipmentRain, snow and sleetSleet*Windblown dustHosedownCorrosive agentsOccasional temporary submersionOccasional prolonged submersion

XX-X----

XX------

XXXX----

XX-XX---

XX-XXX--

XX-XX-X-

XX-XXXXX

For Indoor UseProvides a Degree of Protection

Against the FollowingEnvironmental Conditions

Enclosure Type Number A

Incidental contact with the enclosed equipmentFalling dirtFalling liquids and light splashingCirculating dust, lint, fibers, and flyingsSettling airborne dust, lint, fibers and flyingsHosedown and splashing water Oil and coolant seepageOil or coolant spraying and splashingCorrosive agents

Occasional temporary submersionOccasional prolonged submersion

*Mechanism shall be operable when ice covered

1 2 4 4X 5 6 6P 12 12K 13

XX-

-

---

--

--

XXX

-

---

--

--

XXX

X

XX-

--

--

XXX

X

XX-

-X

--

XXX

-

X--

--

--

XXX

X

XX-

--

X-

XXX

X

XX-

-X

XX

XXX

X

X-X

--

--

XXX

X

X-X

--

--

XXX

X

X-X

X-

--

A Enclosure type number shall be marked on the motor controller enclosure.

Useful Tables



27

mm inches mm inches mm inches mm inches mm inches mm inches

Table A (millimeters to inches)

12

345

678910

1112131415

16

17181920

2122232425

2627

282930

3132333435

3637383940

41

42434445

4647484950

5152

535455

5657585960

6162636465

66

67686970

7172737475

7677

787980

8182838485

8687888990

91

92939495

96979899100

105110

115120125

130135140145150

155160165170175

180

185190195200

210220230240250

260270

280290300

325350375400425

450475500525550

575

600650700750

800850900950

1000

0.03930.0787

0.11810.15740.1968

0.23620.27550.31490.35430.3937

0.43300.47240.51180.55110.5905

0.6299

0.66920.70860.74800.7874

0.82670.86610.90550.94480.9842

1.02361.0629

1.10231.14171.1811

1.22041.25981.29921.33851.3779

1.41731.45661.49601.53541.5748

1.6141

1.65351.69291.73221.7716

1.81101.85031.88971.92911.9685

2.00782.0472

2.08662.12592.1653

2.20472.24402.28342.32282.3622

2.40152.44092.48032.51962.5590

2.5984

2.63782.67712.71652.7559

2.79522.83462.87402.91332.9527

2.99213.0315

3.07083.11023.1496

3.18893.22833.26773.30703.3464

3.38583.42523.46453.50393.5433

3.5826

3.62203.66143.70073.7401

3.77953.81893.85823.89763.937

4.13384.3307

4.52754.72444.9212

5.11815.31495.51185.70865.9055

6.10236.29926.49606.69296.8897

7.0866

7.28347.48037.67717.874

8.26778.66149.05519.44889.8425

10.236210.6299

11.023611.417311.811

12.795213.779514.763715.74816.7322

17.716518.700719.68520.669221.6535

22.6377

23.62225.590527.55929.5275

31.49633.464535.43337.4015

39.37

Table B

decimalfraction

equivalentdecimal

fraction

equivalent

0.01560.03120.04690.06250.0781

0.09370.10940.1250.14060.1562

0.17190.18750.20310.21870.2344

0.250.26560.28120.29690.3125

0.32810.34370.35940.3750.3906

0.40620.42190.43750.45310.4687

0.48440.5

1/641/323/641/165/64

3/327/641/89/645/32

11/643/16

13/647/32

15/64

1417/649/32

19/645/16

21/6411/3223/64

3/825/64

13/3227/647/16

29/6415/32

31/641/2

0.51560.53120.54690.56250.5781

0.59370.60940.6250.64060.6562

0.67190.68750.70310.71870.7344

0.750.76560.78120.79690.8125

0.82810.84370.85940.8750.8906

0.90620.92190.93750.95310.9687

0.98441.0

33/6417/3235/649/16

37/64

19/3239/64

5/841/6421/32

43/6411/1645/6423/3247/64

3/449/6425/3251/6413/16

53/6427/3255/64

7/857/64

29/3259/6415/1661/6431/32

63/641

How to use conversion table A and BTo convert millimeters to inches:

a) 27 mm - from table A, 27 mm = 1.0629é

+ from table B, 0.0629 ! 1/16é Therefore 27 mm ! 1-1/16é

b) 295 mm - from table A, 290 mm = 11.4173é + 5 mm = 0.1968é

+ from Table B, 0.6141 ! 39/64é Therefore 295 mm ! 11-39/64é

To convert to... multiply by....

AtmospheresCubic centimetersCubic InchesFeetGallons (Br. imp.)Gallons (U.S.)

GramsHPKilogramsKilograms

kilograms

KilometersKilowattsJoulesLitersLitersMeters

MetersMilesMillimetersNewton (force)Ounces (avoirdupois)

PoundsTons (2,000 lb)

Tons (2,240 lb)Yards

Newton meter

pounds per square inchcubic inches

cubic centimetersmeterslitersliters

ounces (avoirdupois)kilowattspounds

tons (2,000 lb)

tons (2,240 lb)

milesHP

caloriesgallons (Br. imp.)

gallons (U.S.)feet

yardskilometers

inchespoundsgrams

kilogramskilograms

kilogramsmeters

foot-pounds

14.70.06102

16.390.30484.5463.785

0.03530.74572.205

0.001102

0.0009842

0.62141.3410.2390.220

0.26423.281

1.0941.609

0.039370.224828.349

0.4536907.18

1016.00.9144

.737

BP-2122001901801701601501401301201101009080706050403020100

100

90

80

70

60

50

40

30

20

10

0

-10

-20

F C

FP-

Useful Tables



E-Mail: [email protected]: www.moeller.net

© 2003 by Moeller GmbH

Subject to alterations

VER1210+1280-928GB MDS /Meinke (03/03)

Printed in the Federal Republic of Germany (03/03)

Article No.: 267952

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