Westinghouse Motor Control Center (MCC) Breakers. · Westinghouse has been the world leader in molded case circuit breaker technology since inventing the DE.IONe arc extin-guisher

)WestinghouseNuclear ServicesP.O. Box 355Pittsburgh, Pennsylvania 15230-0355USA

U.S. Nuclear Regulatory Commission Direct tel: (412) 374-4643Document Control Desk Direct fax: (412) 374-4011Washington, DC 20555-0001 e-mail: [email protected]

Our ref: LTR-NRC-06-47

August 8, 2006

Subject: Westinghouse Motor Control Center (MCC) Breakers

Recently Mr. Christopher Even of the U.S. NRC requested technical information about WestinghouseMotor Control Center (MCC) breakers to provide information explaining the basic principle of howthe breakers operate and what problems are associated with the breakers. The attached documents arenon-proprietary and are provided per NRC request.

Attachment 1 contains basic breaker information including the history of the product line, along witha breaker's basic function.

Attachment 2 contains technical data for the AB DE-4ON® classic breakers. Along with generalinformation, catalog cut sheets for EB, EHB, FB and HFB breakers are included. Finally a sampletime current curve and sample dimension sheets are provided.

The issue of grease degradation appears to be a common problem that was identified as early as 1993(reference NRC Information Notice 93-26). Over time, the lubrication properties of the grease withina molded case circuit breaker degrades. This phenomena is not isolated to the Classic Series breaker.However, since it was brought to our attention, Westinghouse has published three technical bulletins,the last being TB-06-2. The plants' maintenance surveillance programs should detect this degradationbefore the function of the breaker becomes a safety issue.

If there are any questions, please contact J. A. Gresham, Manager, Regulatory Compliance and PlantLicensing at 412-374-4643.

Very truly yours,

BI.F(. rerAinManager

Regulatory Compliance and Plant Licensing

cc: Christopher Even, USNRC

Attachments:1. A Working Manual on Molded Case Circuit Breakers2. Technical Data for AB DE-ION® Circuit Breakers

A BNFL Group company

Westinghouse Non-Proprietary Class 3

LTR-NRC-06-47Attachment 1

A Working Manual on Molded Case Circuit Breakers

Page numbers included in Attachment 1 are as follows:Cover PagePages 6, 8, 9, 10, 11, 14, 15, 16, 17, 18, 19, 20, 21, 22, 160, 161,162, 163, 164 and 165

Westinghouse Electric Company LLCP.O. Box 355

Pittsburgh, PA 15230-0355

© 2006 Westinghouse Electric Company LLCAll Rights Reserved

-; j

A Working Manual onMolded Case Circuit Breakers

FOURTH EDITION

I

SECTION 3INTRODUCTION

Westinghouse has been the world leaderin molded case circuit breaker technologysince inventing the DE.IONe arc extin-guisher over 60 years ago. A history ofInnovative concepts converted to practicalapplications has permitted Westinghouseto maintain its circuit protection leader-ship role since that time.

HistoryThe need for molded case circuitbreakers was created in 1918 whennumerous applications for electricalmotors resulted in a demand for a devicethat would ensure safe operation and, atthe same time, protect electrical circuits.During this period, individual motors wereused for the first time In Industrial plants tooperate machine tools, and in privatehomes to operate appliances. Plant elec-tricians were constantly changing fusesblown during motor start.ups because ofthe lack of properly designed fuses formotor circuit protection. Homes experi-enced similar problems when electricalcircuits were overloaded. Inspectors wereconcerned about fire hazards, because ofplug fuses being bridged with penniesand the installation of fuses with too highof an ampere rating. Inspection authoritiesbecame involved and attempted to find asolution to the problem. Meetings withswitch manufacturers were initiated in aneffort to find a solution. Switch manufac-turers were asked to develop a switchingdevice that would interrupt a circuit underprolonged overload conditions. Thedevice would have to be safe, reliableand tamperproof. It should also be reset-

table so as to be reusable after an inter-ruption without replacing any parts. Thissearch for better circuit protection resultedin many different but unacceptableapproaches to the problem. These earlymeetingsand subsequent efforts preparedthe groundwork for the eventual develop-ment of the molded case circuit breaker.

During this period of research anddevelopment, Westinghouse producedthe DE-ION arc extinguisher for use inlarge oil circuit breakers. Although toolarge In its initial form to be practical forsmall circuit breakers, the arc extin-guisher was eventually modified into ausable size. The first compact, workablecircuit breaker was developed in 1923when the modified arc extinguisher wascoupled with a thermal tripping mech-anism. It was not until four years later,however, that Westinghouse researchengineers found the ideal combination ofmaterials and design that permitted circuitbreakers to interrupt fault currents of5000A at 120 volts AC or DC. One yearlater, Westinghouse placed the first circuitbreaker on the market. Its acceptancewas instantaneous.

Since that initial introduction In 1927,Westinghouse has been at the forefrontof circuit breaker technology with anunprecedented series of circuit protectiveenhancements and introductions.

The Westinghouse Motor Circuit Protector(MCP) was introduced In the late 1960sand was the first device of its kind to bespecifically designed for use on motorcircuits.

Standard thermal magnetic circuitbreakers remained state-of-the-art until1973 when Westinghouse introduced theSeltronicTM Circuit Breaker. Seltronic wasthe first molded case circuit breaker withan electronic trip unit.

This innovative spirit continued and in1976, the Systems Pow-R Breaker wasunveiled, the most powerful encasedcircuit breaker available.

In 1979, Current Limit-Rý a true current.limiting circuit breaker, was introduced tothe market. The design was based on theWestinghouse exclusive patented slotmotor concept.

Recognizing the need for a world classdevice that would meet the higher andgrowing interrupting requirements of todaywithout sacrificing size, Westinghouseestablished a new world class standardwith the Series U. The Series U family ofmolded case circuit breakers met thechallenge of the 80s and the future.

Westinghouse's history as the worldleader in circuit protection is welldocumented. In this leadership position,Westinghouse has always and continuesto identify the need and introduce innova-tive solutions, all supported by sound,state-of-the-art technology.

6 BREAKER BASICS

*1 i

SECTION 4GENERAL INFORMATION

Definitions

What Is a Circuit Breaker?

A circuit breaker is defined in NEMAstandards as a device designed to openand close a circuit by nonautomaticmeans, and to open the circuit auto-matically on a predetermined over-current, without Injury to itself whenproperly applied within its rating.

A circuit breaker is also defined in ANSIstandards as a mechanical switchingdevice, capable of making, carrying andbreaking currents under normal circuitconditions and also, making, carrying fora specified time and breaking currentsunder specified abnormal circuit condi-tions such as those of short-circuit.

It can be seen that although the basicpremise is the same for both circuitbreaker definitions and both are accurate,the wording is quite different. Trying topresent concise definitions for the manytypes of circuit breakers applied today iseven more involved. Categorizing circuitbreakers is complicated by the fact thatonly the molded case circuit breaker isprecisely defined. For the sake of thisdiscussion, if it is not a molded casecircuit breaker by definition, it isconsidered a power breaker.

There are two classifications and threetypes of circuit breakers used for lowvoltage circuit protection. The two basicclasses of circuit breakers are:1. Low Voltage Power Circuit Breaker

Class2. Molded Case Circuit Breaker Class

The classifications themselves lend theirnames to the first two of the three types ofcircuit breakers and the third type of cir-cuit breaker is derived from the moldedcase class and is known as an insulatedcase circuit breaker. The three types ofcircuit breaker are as follows:1. Low Voltage Power Circuit Breakers

(LVPCB)

2. Molded Case Circuit Breakers (MCCB)

3. Insulated Case (encased) CircuitBreakers (ICCB)

Briefly, some of the salient features ofthese types of breakers are the following.

Molded case circuit breakers, shown inFigure 4.1, as a class, are tested andrated according to the UL 489 Standard.Their current carrying parts, mechanisms,and trip devices are completely containedwithin a molded case of insulatingmaterial. MCCBs are available in smalland medium frame sizes with variousinterrupting ratings for each frame size.Current-limiting molded case circuitbreakers are also available. They arecharacterized by fast interruption short-circuit trip elements but do not have shorttime ratings.

Insulated case circuit breakers are alsorated and tested according to the UL 489Standard. However, they utilize character-istics of design from both classes. Theyare of large frame size, have short timecapabilities and utilize stored energyoperating mechanisms.

Low voltage power circuit breakers areused primarily in drawout switchgear,they have replaceable contacts, and aredesigned to be maintained in the field.Figure 4.2

The term power circuit breaker alsoapplies to medium voltage (1000-72.5 kV)or high voltage (over 72.5 kV) breakers.Figure 4.3

Insulated case power circuit breakers,designed and tested to the UL 489 Stan-dard, are used primarily in fixed mountedswitchboards but are also available Indrawout configuration. They are generallyconsidered not field maintainable butthere are several maintenance operationsthat can be performed in the field.Figure 4.4

Molded case circuit breakers aredesigned and tested to the UL 489 Stan-dard. Some of the larger molded case cir-cuit breakers are available in drawoutdesign. They are used primarily in panel-boards and switchboards where they aremostly fixed mounted.

Figure 4.1 SeriesU FD molded case circuitbreaker.

Figure 4.2 Type DS low voltage power circuitbreaker.

8 BREAKER BASICS

Function Standards

Although molded case and insulatedcase circuit breakers are not field main-tainable, they have relatively highendurance capabilities which should beevaluated in any application analysis.

Preferred ratings of low voltage powercircuit breakers are as Indicated inANSI/IEEE C37.16. Standards for lowvoltage AC power circuit breakers used inenclosures are as indicated in ANSI/IEEEC37.13. Test procedures for low voltagepower circuit breakers used in enclosuresare as indicated in ANSIIIEEE C37.50-1973. Application recommendations arediscussed In ANSIIIEEE C37.16-1980 andapplication factors are discussed in ANSI/IEEE C37.20. Low voltage power circuitbreakers are generally UL listed and canbe UL labeled.

Generally, the best guide for the choiceof a type of breaker to use is to follow thepractices which have a history of longterm successful performance. But, thebest engineering solution in any specificcase may require thorough considerationof alternative approaches.

The subject of molded case circuitbreakers will only be covered beyondthis point. Breaker Basics Volume IIs dedicated to molded case circuitbreakers and their applications.The subject of power breakers andencased breakers, will be detailed Ina similar fashion in Breaker BasicsVolume II.

Molded case circuit breakers are designedto provide circuit protection for lowvoltage distribution systems. They protectconnected apparatus against overloadsand/or short-circuits.

Molded case breakers are designed, builtand tested in accordance with NEMAand/or Underwriters' Laboratories, Inc.standards. In addition, molded casebreakers are designed to be applied inaccordance with the requirements of theNational Electrical Code, which ismandatory.

In addition to the above domestic stan-dards, other international standards mustbe complied with to sell products tovarious world markets. There are manyindividual foreign standards on moldedcase breakers and not all molded casebreaker designs comply with all the samestandards. Some of the major foreignstandards are:• Australian Standards

British Standards Institution (BSI)Canadian Standards Association (CSA)International ElectrotechnicalCommission (IEC)

,• Japanese Industrial Specification

= South African Bureau of StandardsSwiss Electro-Technical Association

t Union Technique de I'ElectriciteVerband Deutscher Elektrotechniker(VDE)

Compliance with these standards and thedomestic standards previously mentioned-satisfies most local and internationalcodes, assuring user acceptability andapplication simplicity. The WestinghouseSeries n family of molded case breakers,because it is a global design, complieswith most major standards worldwide.

Figure 4.3 Type DHP air circuit breaker and type VCP.W vacuum circuit breaker. Figure 4.4 Type SPB insulated case (encased)circuit breaker.

BREAKER BASICS 9

'i ii

SECTION 4GENERAL INFORMATION

Because of the tremendous impact ULstandards and IEC standards have on thedesign and application of molded casecircuit breakers worldwide, U L 489 andIEC 947-2 are specifically recognized inthis section. In addition, refer to Section 11of this publication for an overview of ULand IEC molded case circuit breaker test-ing procedures. Any discussion of thesestandards is meant only as a generaloverview and should not be consideredas a substitute for either of the standards.For a full explanation of either UL 489 orIEC 947-2. consult the complete stan-dards for details and proper conformanceinstructions.

NationalIn general, Westinghouse molded casecircuit breakers are UL listed in accord-ance with UL 489. UL listed circuitbreakers are identified by the UL listingmark, frequently referred to as the ULlabel as shown in Figure 4.5. This listingis generally limited to circuit breakersequipped with inverse time and instan-taneous (or short time) time-currentcharacteristics.

Circuit breakers (interrupters) equippedwith instantaneous only time-currentcharacteristics are also covered underUL 489. These type devices, however, areclassified as recognized componentsand bear the reversed UR marking.Figure 4.6

Molded case switches (or circuit inter-rupters) are designed, built and tested inaccordance with UL 1087. Much of thetest performance criteria is the same asestablished for molded case circuitbreakers under UL 489. Products testedunder UL 1087 are listed as molded caseswitches and bear a suitably identifiedlisting mark.

Although the Canadian Standards Asso-ciation (CSA) falls into the category of amajor international standard, design, sub-mittal and follow-up test requirements forCSA are essentially the same as requiredby UL. In fact, harmonization programsbetween UL and CSA are underway toclose the gap on any differences.

Most Westinghouse molded case circuitbreakers are listed by the Canadian Stan-dards Association and bear the CSAmonogram as shown in Figure 4.7. Circuitbreakers so marked are listed under CSAStandards C22.2, No. 5-M 1986.

UL489UL listed molded case circuit breakersmust conform to the Underwriters Labo-ratories, Inc. Standard for Safety, No.UL 489. The following brief explanation ofUL 489 illustrates why the UL listing markexemplifies dependability and quality.

Underwriters Laboratories, Inc., is anindependent not for profit organizationwhich performs or witnesses testing onelectrical devices, materials and systemsto insure their safety for people and pro-perty. Only upon successful completionof all prescribed tests is the UL listingmark granted.

Molded case circuit breakers mustundergo three distinct phases of tests asdefined per UL 489:

1. Initial Submittal

2. Initial Production Inspections

3. Follow-up Testing

Before any circuit breaker could be con-sidered for initial submittal testing, it mustfirst be designed in accordance with theconstruction requirements defined in UL489. These requirements define specificacceptance criteria including:

1. General Details

2. Corrosion Protection

3. Insulating Materials

4. Current Carrying Parts

5. Wiring Terminals

6. Operating Mechanisms

7. Spacings(creepage and clearance distances)

Figure 4.5 UL label. Figure 4.6 UR marking for recognizedcomponent.

Figure 4.7 Canadian Standards Associationmonogram.

CP

10 BREAKER BASICS

International Electrotechnical Commission(IEC)

Standard IEC 947-2, which replaced IEC157-1, applies and covers test require-ments for circuit breakers up to ratingsnot exceeding 1000 volts AC. This stan-dard covers molded case circuit breakersnormally covered by UL 489. as well aslow voltage AC power circuit breakersnormally covered by UL 1066 andANSI C37.50. The performance andwitnessing of IEC tests can take place ina number of independent internationallaboratories, such as KEMA in theNetherlands and CESI in Italy.

Every device tested to IEC 947-2 must besubjected to several test sequences inorder to be officially approved. The testsequences are intended to check differ-ent parts of the device's characteristicsover a number of different samples. SinceIEC 947-2, unlike UL 489, covers bothstandard low voltage molded case circuitbreakers, as well as low voltage powercircuit breakers, the exact test sequencesperformed depends upon the category ofthe device. A "Category A" device would,in general, be a device without a with-stand rating, while a "Category B" devicewould have a withstand rating. Therefore,most standard molded case circuitbreakers would fall Into "Category A:' andpower circuit breakers into "Category B'

IEC 947-2 was developed with assistancerendered by members of the US NationalCommittee. Still, a number of differencesexist between IEC 947-2 and the abovementioned domestic standards. Therefore,any product comparisons made betweenproducts tested to each of these stan-dards (domestic and international) shouldonly be made with a thorough under-standing of the differences that exist.

SUMMATION

There is no room for compromise whenperformance, quality and safety areinvolved. Exacting standards areestablished relative to the design, testingand manufacture of molded case circuitbreakers, and compliance with thesemajor standards insures the best selec-tion. Understanding the sometimes subtledifferences between sets of standardscan make a significant difference in thefinal selection.

Molded case circuit breakers designed,built and tested in accordance withestablished UL, CSA and IEC standardsoffer a high level of quality performance.This performance, as is the case with ULand CSA approved devices, is evenregularly verified by established follow-upand audit test programs. It is not prudentnor recommended to make device selec-tions based on a superficial understand.ing of the standards a particular devicecomplies with, because of the differencesthat exist from one set of standards toanother. The selection process has beensimplified, however, by the availability ofmolded case circuit breakers that aredesigned, tested and meet a wide rangeof both national and international stan-dards. Figure 4.8

Figure 4.8 General standards influences around the world.

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BREAKER BASICS 11

SECTION 5CIRCUIT BREAKER COMPONENTS

Molded Case (Frame)

Although many types of molded casecircuit breakers are manufactured, all arecomprised of five main components asshown In Figure 5.1:

= Molded Case (frame)" Operating Mechanism" Arc Extinguishers" Contacts

" Trip Units

Figure 5.1

The function of the molded case is to pro-vide an insulated housing to mount all ofthe circuit breaker components. Thecases are molded from moldarta and/orglass-polyester material that combinesruggedness and high dielectric strengthin a compact design.

Each different type and size of moldedcase is assigned a frame designation.Frames are identified by letters such asFD, JDC, KW, etc. This frame identifica-tion describes a number of importantcharacteristics of the breaker, i.e., maxi-mum voltage and current ratings, inter-rupting ratings, standards met andphysical dimensions of the molded case.Unfortunately, all manufacturers have adifferent identification system becausethe breaker's characteristics are different.For example, a Westinghouse Series UBreaker has three different interruptingratings in the same physical frame size,while another manufacturer might have touse three physically different packages.Figure 5.2

Figure 5.2 Figure 5.3 DE-ION arc quenchersextinguishing arc.

14 BREAKER BASICS

IS

Operating Mechanism Arc Extinguishersand Contacts

The function of the operating mechanismis to provide a means of opening andclosing the breaker. This toggle mechanismis the quick-mnake, quick-break type,meaning that the speed with which thecontacts open or close is independentof how fast the handle is moved. Thebreaker is also trip-free, which means itcannot be prevented from tripping byholding the breaker handle in the "ON"position. The handle position indicatesthe contact status: closed, open or tripped(a midway position). To restore serviceafter the breaker trips, the handle mustfirst be moved from the center position(tripped) to "OFF." to reset the mechan-ism, and then to "ON.' This distinct trippoint is particularly advantageous wherebreakers are group mounted, such as inpanelboard applications, because thehandle position clearly indicates the faultycircuit. The Westinghouse Series U designalso incorporates a push to trip mechan-ism which provides a manual means ofexercising the mechanism by manuallytripping the breaker. This is accomplishedby depressing the button located in thetrip unit, the rating plug or circuit breakercover, depending on the specific frame.

The function of the arc extinguisher is toconfine, divide and extinguish an arceach time a breaker interrupts a current.An arc extinguisher, therefore, dissipatesarcs that result when the circuit breakerinterrupts current flow, see Figure 5.3.Each arc extinguisher consists of a stackof U-shaped steel plates held together bytwo insulating side plates as diagramed inFigure 5.4. When an interruption occursand the contacts separate, the currentflow through the ionized region betweenthe contacts induces a magnetic fieldaround the arc and arc extinguisher.As the lines of magnetic flux show, theforce drives the arc into the steel plates,deionizing the gas while dividing andcooling the arc as shown in Figure 5.5.See the Glossary Section for a discus-sion of magnetic flux.

Standard molded case circuit breakersutilize a linear current flow contactarrangement. A small blow-apart forcebetween the contacts is generated undershort-circuit conditions, which helps toopen the contacts. The majority of theopening action, however, is caused bythe mechanical energy stored in the tripmechanism itself. This has been the con-ventional approach since Westinghousedeveloped the DE-ION arc extinguisherduring the early 1900s.

Refinements have been made to the arcextinguisher since those early years, butnot until the use of the reverse loop con-tact design have significant strides beentaken in the direction of improved arcextinguishing. The reverse loop designtakes advantage of a physics' principlethat describes what happens when cur-rent flows in essentially opposite paths.A much greater blow-apart force betweenthe contacts is generated with the reverseloop design. This blow-apart force isdirectly proportional to the size of the faultcurrent; the greater the fault, the greaterthe force. This force assists with rapid arcextinguishing by causing faster contactopening speeds.

The reverse loop design opened the doorfor new breaker designs, such as the Cur-rent Limit-R and the entire Series U family.Figure 5.6

Detailed information on contact designsand their operation can be found inSection 12 of this publication.

Figure 5.4 Arc extinguisher. Figure 5.5 Arc extinguisher operation. Figure 5.6

StandardLinear Design

Reverse LoopDesign

CurrentRow

BREAKER BASICS 15


Trip Units Thermal Conditions Short-Circuit Conditions

The function of the trip unit is to trip theoperating mechanism in the event of aprolonged overload or short-circuitcurrent. To accomplish this, electro-mechanical (thermal magnetic) or elec-tronic trip units are provided. Today'ssophisticated electronic trips also incor-porate protection against damaging arc-ing ground faults. The more sophisticatedthe electronic trip unit, the more versatileit becomes, offering electrical testing inthe field, precise trip curve shaping, aswell as monitoring and recording capabil-ities. Electronic trip units are covered inmore detail later in this section and inSection 7 of this publication.

The traditional molded case circuit breakerhas used electromechanical (thermalmagnetic) trip units since Westinghouseinvented the molded case circuit breaker.Protection is provided by combining atemperature sensitive device with a cur-rent sensitive electromagnetic device,both of which act mechanically on the tripmechanism.

Molded case circuit breakers utilize oneor a combination of different trip elementsto provide the required circuit protectionfor a particular application. These tripelements protect against three conditions:thermal overloads, short-circuits and arc-ing ground faults. Each of the three condi-tions is discussed first, followed by thedifferent molded case breaker methodsused to protect against any or all of theseundesirable conditions.

Insulation deterioration in electrical con-ductors is usually the result of overloadconditions. When an overload conditionexists, a temperature buildup occursbetween the insulation and the conductor.Uncontrolled, this excessive heat willreduce the life of the conductor andeventually result in a short-circuit as theinsulation fails.

The heat in a conductor depends on thesquare of the rms current (12), the conduc-tor resistance (R) and the time (t) the cur-rent flows. If the current flowing into aconductor and the time for which it flowsis monitored, overload conditions arepredictable and can be detected.

A time-current curve shows the boundarybetween the normal and the overloadcondition. A typical time-current curve forthe thermal (overload) element of a circuitbreaker protective device indicates that atrip will occur in 1800 seconds at 135%of rating (Point A) or ten seconds at 500%of rating (Point B). Figure 5.7

A circuit protective device uses time-current curves to indicate when it willoperate to protect a conductor againstoverload conditions. Just how a moldedcase circuit breaker performs this functionis covered in detail later in this section.

Short-circuit currents (fault currents)usually occur when abnormally high cur-rents flow duo to the failure of the insula-tion. When the insulation between phasesor between phases and ground breaksdown, short-circuit currents, limited onlyby the capabilities of the distributionsystem, can be expected to flow into thefault. The short-circuit must be eliminatedquickly to protect against damage fromthe resulting thermal and dynamicstresses.

A typical time-current curve for a short-circuit (instantaneous) element of a circuitbreaker indicates that a trip will not occuruntil the fault current reaches or exceedsPoint A as shown in Figure 5.8. Themethods used by a molded case circuitbreaker to protect against a short-circuitare also addressed in detail later in thissection.

For a more detailed discussion of short-circuit conditions, see Section 10.

Figure 5.7 Typical time-current curve for 100Athermal element of a breaker.

Figure 5.8 Typical time-current curve for fixedmagnetic action.

10

A

.016

Current -

16 BREAKER BASICS

A &

Ground Fault Conditions Types of Trip Unit

A ground fault is one particular type ofshort-circuit. It is a short-circuit betweenone phase andground, and is probablythemost common type of fault experiencedon low voltage systems. Arcing groundfault currents are often not of a largeenough magnitude to be detected by thestandard protective device. Undetected,the ground fault current can develop intoa current value high enough to trip thestandard protective device. By this time, itis often too late and the damage has beendone. This is especially true with motorswhere an Internal insulation failure canresult in serious damage.

Traditionally, when an electrical systemrequired the detection of ground fault cur-rents, separate ground fault protectiondevices were used to provide the addi-tional level of protection. With the adventof electronic trip circuit breakers, groundfault protection has become an integralpart of the trip unit. Ground fault protec-tion as part of an electronic trip unit isdiscussed in Section 7 of this publication.

The National Electrical Code requiresground fault protection on specific appli-cations, such as service entrance. NECrules are dependent upon such factors asthe service's current rating, the voltagelevel and the type of system.

Fixed or Interchangeable Trip Unit

Conventional molded case circuit breakersare available with either a fixed or inter-changeable electromechanical trip unit,depending on the type and frame size.With a fixed trip breaker, the entirebreaker must be replaced if a new triprating is required. With an interchange-able trip breaker, only the trip unit has tobe changed, up to the maximum currentrating of the breaker frame.

Series U molded case circuit breakersoffer one additional interchangeabledimension, an interchangeability betweenelectromechanical and electronic tripunits within the same frame. Figure 5.9shows a Series U HLD breaker with aninterchangeable electronic trip unitinstalled and a separate interchangeableelectromechanical trip unit. The tripunits can be interchanged with nomodifications.

All interchangeable electromechanicaltrip breakers have adjustable magneticelements which provide short-circuit pro-tection. Certain smaller breaker framesizes are sealed units, as required by UL,and are not interchangeable trip unitbreakers. The magnetic element on thesesealed breakers is not adjustable. Figure5.10 shows a Series U FD 150A framebreaker with factory seal affixed to theside of the case, indicating this particularbreaker is a sealed unit.

Fixed Thermal and Adjustable ThermalSettings

Electromechanical trip circuit breakerscontain thermal trip elements which pro-vide overload protection. This thermalelement can be either fixed or adjustable.Except for adjustable electronic trips, ULregulated circuit breakers can only utilizea fixed thermal element. IEC regulatedcircuit breakers can utilize either a fixedor adjustable thermal element.

Figure 5.9 Series'C HLD circuit breaker with interchangeable Seltronic (electronic) trip unit. Figure 5.10

BREAKER BASICS 17


Electromechanical

Conventional breakers utilize bimetalsand electromagnets to provide overloadand short-circuit protection. This type ofprotective action is referred to as thermalmagnetic and has been the industrystandard. Today, however, electronicdevices play a much greater role, withcontinued use growth expected. To betterunderstand this tripping action, the ther-mal and magnetic portions are explainedseparately and then combined.

Thermal (Inverse Time)Overload ProtectionThermal trip action is achieved throughthe use of a bimetal heated by the loadcurrent. On a sustained overload, thebimetal will deflect, causing the operatingmechanism to trip. The time needed forthe bimetal to bend and trip the circuitbreaker varies inversely with the current.Figure 5.11

A bimetal consists of two strips of metalbonded together. Each strip has a dif-ferent thermal rate of heat expansion.Heat due to excessive current will causethe bimetal to bend or deflect. The metalhaving the greater rate of expansion willbe on the outside (longer boundary) ofthe bend curve. To trip the breaker, thebimetal must deflect far enough tophysically push the trip bar and unlatchthe contacts. Figure 5.12

Figure 5.11 Deflection is predictable as a function ofcurrent and time. as explained earlier inthis section as shown in Figure 5.13. Thismeans, for example, Ihat a typical 100Abreaker might trip in 1800 seconds at135% of rating (Point A) or ten seconds at500% of rating (Point B). Consequently,bimetals provide a long time delay onlight overloads, yet have a fast responseon heavier overloads.

Thermal elements are calibrated at thefactory and are not field adjustable for ULregulated applications. A specific thermalelement must be supplied for each cur-rent rating. For example, a Series U FDbreaker is available from the factory withvarious thermal elements ranging from 15to 150A. The thermal element cannotexceed 150A because an FD breaker isbuilt on a 150A frame.

Where IEC standards apply to the appli-cation, the thermal element can be adjust-able. IEC regulated versions of Seriesthermal magnetic circuit breakers withadjustable thermal settings have anadjustment button in the breaker cover.Turning the adjustment button changesthe gap distance between the bimetaland trip bar. By varying the bimetal traveldistance, the thermal rating is changed.Figure 5.14

Figure 5.12 Thermal action.

Figure 5.13 Typical time-current curve forI00A thermal element of a breaker.

Figure 5.14 FW breaker with adjustablethermal settings.

Figure 5.16 Typical time-current curve for fixedmagnetic action.

10

E

.016

ACurrent

18 BREAKER BASICS

1k

Magnetic (Instantaneous)Short-Circuit Protection

Magnetic trip action is achieved throughthe use of an electromagnet whose wind-ing is in series with the load current. Whena short-circuit occurs, the current passingthrough the circuit conductor causes themagnetic field strength of the electro-magnet in the breaker to rapidly increaseand attract the armature. As the armatureis attracted to the electromagnet, thearmature rotates the trip bar causing thecircuit breaker to trip as diagramed inFigure 5.15. The only delay factor is thetime it takes the contacts to physicallyopen and extinguish the arc. The actiongenerally takes place in less than onecycle and trips the breaker instantane-ously, without any intentional delay.A typical magnetic time-current curve isillustrated in Figure 5.16 and indicatesthat the breaker will not trip until thecurrent reaches or exceeds Point A. Theopening speed of the contacts is depen-dent on the actual contact design, not justthe operating mechanism itself. CertainSeries U contact designs provide addi-tional assistance to the opening cycle,resulting in improved arc extinguishing.

Magnetic elements can be either fixed oradjustable, depending upon the type ofbreaker and frame size. For example,most thermal magnetic breakers abovethe 150A frame size have adjustablemagnetic trips.

With adjustable Series C models, themagnetic element of each pole of the tripunit can be adjusted by rotating adjust-ment buttons in the breaker cover, seeFigure 5.17. The buttons have several set-tings with values in multiples of the tripunit ampere rating. Spring tension on themagnet armature is changed when adjust-ments are made, resulting in differentmagnetic settings.

A similar curve for an adjustable magneticelement demonstrates how the adjust-ment buttons move the curve from left toright as the magnetic trip is increased.see Figure 5.18. On the lowest setting, thebreaker will not trip magnetically until thecurrent reaches or exceeds Point A. Asthe magnetic setting is increased, the cur-rent trip point changes, as shown on theadjustable magnetic curve. The mechan-ism is continuously adjustable over theentire range, from the lowest setting to thehighest setting.

Figure 5.15 Magnetic action.

Magnetic Element

Magnetic Element Closes Gapand Opens Contacts on Short-Circuit

Trip Bar

J,,rCCloedLoad Lineotas

Latch

Figure 5.17 Sedes C HJD breaker with adjustable magnetic settings. Figure 5.18 Typical time-current curve foradjustable magnetic action.

Current.--

BREAKER BASICS 19


Electronic

Thermal Magnetic(Overload and Short-Circuit Protection)

Thermal magnetic trip units combine thefeatures of both the thermal and magneticactions as illustrated in Figure 5.19. Forexample, Points A and B on the illustratedtrip curve show both the thermal andmagnetic action for a typical 1O0A FDbreaker as shown in Figure 5.20. A 250%overload would take approximately 60seconds before the bimetal would deflectfar enough to trip the breaker. However, ifinstead of an overload there was a short-circuit that was 4000% (40 times) of thebreaker rating, the electromagnet in thebreaker would attract the armature andtrip the breaker in less than one cycle.

A thermal magnetic trip unit is best suitedto most general purpose applicationsbecause it is temperature sensitive andautomatically tends to follow safe cableand equipment loadings which vary withambient temperatures. Thermal magnetictrip units always act to protect the con-ductors, safeguarding equipment underhigh ambient conditions and permittinghigher safe loadings under low ambientconditions. They do not trip if the overloadis not dangerous, but will trip instantly dueto heavy short-circuit currents.

Westinghouse introduced the first moldedcase circuit breaker with an internallymounted electronic trip unit in 1973, seeFigure 5.21. Since the introduction ofthe Seltronic line of molded case circuitbreakers with electronic trips, circuitprotection has experienced tremendouschanges in this area. Today, precisecurve shaping, integral ground fault pro-tection, system monitoring, data gatheringand information dissemination are rapidlybecoming circuit breaker standards.

Molded case circuit breakers with con-ventional thermal magnetic trip units areincreasingly being replaced by electronictrip units. This is especially true for thelarger frame sizes. The result is increasedaccuracy, repeatability and discrim-ination. Another major advantage is theoption of built-in ground fault protection.Previously, with thermal magnetic breakers,a separate ground fault relay was used totrip the breaker with a shunt trip.

In general, electronic trip systems arecomposed of three component items asshown in Figure 5.22. First, a currenttransformer (sensor) in each phase tomonitor and reduce the current to theproper level for input into a printed circuitboard. Second, the printed circuit boardcan be viewed as the brains of the system,since it interprets input and makes adecision based on predetermined param-eters. A decision to trip results in the cir-cuit board initiating an output to the third

component, a low power flux-transfershunt trip which trips the breaker. Anexternal source of tripping power is notrequired.

Electronic circuitry has been changingand improving rapidly. Earlier electronictrip units used analog circuitry, which isconsidered the conventional approach.An analog device looks at all the points ona particular curve and responds to peakvalues. The analog device remains astrong contributor to circuit protection.Figure 5.23

As the demand for more sophisticatedsystems grew, so did the popularity of themicroprocessor-based trip unit. The useof a microprocessor not only providesadditional capabilities, it allows the tripsystem to perform a number of standardfunctions even better. A microprocessor(digital device) looks at selected discretepoints on a particular curve and makes asummation of those discrete points whichresults in a root mean square (rms) value,in lieu of a peak value. The rms value issometimes referred to as the effectivevalue. The result is a more realistic overallview of a given set of circumstances.Figure 5.24

Figure 5.19 Thermal magnetic action. Figure 5.20 Typical trip curve for 100A thermalmagnetic breaker.

ThermalA - Action

E ' -- Magnetic

Figure 5.21

.016 - B

A4ction

Magnetic Element

Trip BarBi "et/ Contacts

Element /- ClosodLoad -- LiUno

Latch

20 BREAKER BASICS

250% 400w%

r %

Circuit breakers, because of tremendous Figure 5.22advancements in trip technology, are nolonger viewed as individual devices. Acircuit breaker is expected to be a self-contained system performing many func- Frame

tions over and above its basic equipment Frameprotection duties.

Previously used for alternating current(AC) applications only, electronic tripdevices now can be used for direct cur-rent (DC applications also. Westinghousedeveloped a unique device to replacecurrent transformers, because currenttransformers cannot be used with directcurrent. This development has openedthe door for electronic trip unit applica-tions in industries where DC power is ofcritical importance. The UninterruptiblePower Supply (UPS) industry is just oneexample. See Section 14 for additionalUPS Industry and DC circuit breaker T Eapplication information. :.g>

Detailed information concerning elec-tronic trip units, how they function, theirapplications and future developments canbe found in Section 7.

Solid-State Circuitry ShuntTrip(internal) u(internal)

Current Transformer(Internal)

Figure 5.23 Figure 5.24

x -Peak Value (Current) x - Discrete Values (Current)Peak Value (Curent)

(Time) -(Time)

BREAKER BASICS 21

Ir . *


Trip Unit Optionsand Modifications

On standard thermal magnetic moldedcase circuit breakers, the selected tripunit determines In a somewhat narrowrange, just how and when Ihe breakerwould act relative to a particular systemcondition. As discussed earlier in this sec-tion, the thermal element safely reacts tooverload conditions and the magneticelement reacts to short-circuit conditions.If there was a need for ground fault pro-tection, external devices were added. Anychange in the specific parameters requiredchanging of the trip unit or even the entirecircuit breaker.

Electronic trip units greatly increase theflexibility of circuit breakers. This flexibilityhas also introduced the frequent use ofterms and/or phrases normally associatedwith metal frame power circuit breakers.Although most are familiar and commonlyused, they are briefly covered here as areference aid for later sections of thispublication.

Selectivity

The responses to a set of circuit or systemconditions (usually in terms of current)within a specific time frame. In short, it isthe ability to discriminate. The degree ofselectivity is normally limited by thesophistication of the trip unit and thephysical ability of the circuit breaker towithstand the thermal and mechanicalstresses of a fault current.

Instantaneous Pickup

A preselected value of current where atrip action will take place immediately withno intentional time delay. This function issimilar to the magnetic function of a ther-mal magnetic breaker.

Long Time Pickup and Delay

A preselected value of current that abreaker will carry continuously for apredetermined period of time. Once thepickup point is reached and the timingcycle begins, a trip action will not takeplace until the time delay has beenachieved. This function is similar to thebimetal effect in a thermal magneticbreaker as it reacts to overload con-ditions.

Short Time Pickup and DelayThis function is similar in operation to longtime pickup and delay, except currentvalues are higher and time framesshorter. This function protects against lowlevel short-circuits.

Ground Fault Pickup and Delay

The pickup function determines at whatpoint a ground fault will be identified andthe delay determines how long the tripaction will be delayed after the fault hasbeen identified.

Note: In the case of all pickups, thepickup value, which initiates the timingcycle, must be maintained throughout thetiming cycle for tripping to occur. If condi-tions change and the pickup value is notmaintained, the tripping system resets inanticipation of another timing cycle.

Special Calibrations and Applications

Certain operating conditions and ambienttemperatures will affect the operation oftrip units. In some situations, a deratingfactor is applied and in other instancesit is necessary to recalibrate. Refer toSection 9 (Application and Selection)of this publication for details concerningspecial operating conditions.

Electronic trip units are temperatureinsensitive over a wide range of tempera-tures. Because of this advantage, elec-Ironic trip units have replaced the needfor special breakers to operate in unusualambient conditions.

An ambient compensated breaker isspecially calibrated to properly funclion ina specific, other than standard, ambienttemperature. These specially calibratedcircuit breakers are still available fromWestinghouse.

22 BREAKER BASICS

GLOSSARY

(The terms and phrases contained inthis Glossary are defined as used in thecontext of this publication, and are notintended to be all inclusive definitions. Inmany instances, you will be asked to referto a specific page and section for a defini-tion and/or discussion. Some terms and/or phrases are used, but not covered indetail in any specific section. In thosecases, a definition or discussion ispresented in the Glossary.

AC (Alternating Current)

Alternating current, normally representedas a sine wave, is the most commonlyused type of electrical power. As its namesuggests, alternating current flows in onedirection and then changes, or alternates,and flows in Ihe opposite direction(usually generator produced).

Alternating current flows from the nega-tive terminal of the power source to thepositive terminal. However, the polarityof the power source terminals changeperiodically, causing the direction ofcurrent flow to also change periodically.

The characteristics of alternating currentmake it less expensive to transmit overlong distances than DC (direct current),without excessive power losses. This isthe primary reason utility companiesproduce alternating current.

ANSIAmerican National Standards Institute

ANSI is an independent standardsauthorizing organization associated with awide range of industries, equipment andprocesses, of which the electrical industryis part. For example, power circuitbreakers and their enclosures are regu-lated by recognized standards publishedby ANSI. ANSI, as a standards authoriz-ing organization, does not establishspecific standards. It goes through a con-sensus process within a particular indus-try, and ultimately publishes recognizedconsensus standards established by allparticipants within the particular industry.See Section 4, page 8.

Accuracy

See Section 7, page 38.

Alarm Switch


Altitude


Ambient Compensated

Ambient compensated is normally usedto describe an electromechanical circuitbreaker whose trip element is calibratedand/or adjusted to perform as required ina specific ambient temperature condition.

Ambient TemperatureSee Section 9, page 78.

Analog DeviceSee Section 5, page 20 and Section 7,page 45.

ArcingArcing is the discharge of electric currentacross a gap between two points. Arcingoccurs between breaker contacts eachtime a breaker interrupts a current.

Arcing ContributionSee Section 10, page 85.

Asymmetrical CurrentAn asymmetrical current wave is not sym-metrical about the zero axis. The axis ofsymmetry is offset from the zero axis, withthe magnitude above and below the zeroaxis unequal. See Section 10, page 83.

AtmosphereSee Section 9, page 79.

Auxiliary SwitchSee Section 6, page 25.

BimetalSee Section 5, page 18.

Blow-Apart ForceSee the Electromagnetics discussion inthe Glossary and Section 12, page 108.

Bolted Fault (Bolted Short-Circuit)The bolted fault is a short-circuit almostalways of a very high magnitude. Theprincipal effects of a high value short-circuit are heating and magnetic stresses,with both effects varying as the square ofthe current. See Section 5, page 16.

Branch CircuitA branch circuit is comprised of the circuitconductors and components between thefinal overcurrent device protecting the cir-cuit and the equipment, such as a motor.See Main and Feeders.

160 BREAKER BASICS

BusBus is the conductor or conductors,usually made of copper or aluminum,which carries the current and serves asa common connection for two or morecircuits.

CSACanadian Standards Association


CalibratedWhen a device, such as a circuit breakertrip unit, is adjusted or has its adjustmentssystematically standardized for a specificoperating range, it is referred to ascalibrated.

Characteristic Curve

See Time-Current Curve.

ChargeThe process of storing energy in theclosing springs of a breaker by eithermechanical or electrical means.

ChipA minute piece of a thin semiconductingmaterial, such as silicon or germanium.processed to have specified electricalcharacteristics. See Section 7, page 44.

Circuit Breaker


Circuit ProtectionSee Section 10, page 86.

Clearing Time

Fuse -The total elapsed time between thebeginning of the specified overcurrentand the final interruption of the circuit atrated voltage. It is the sum of the meltingtime and the arcing time.

Mechanical Switching Device(Circuit Breaker) -The total elapsed timebetween the time the specified over-current causes a release device to beactuated and the instant of final arcextinction on atl poles of the primaryarcing contacts.

Conductor ProtectionSee Section 10. page 86.

Connecting StrapsSee Section 6, page 28.

Current LimiterSee Section 6, page 31.

Current-LimitingSee Section 14, page 145.

ContactSee Section 6, page 25 for those listedbelow:, "a" Contact- "b" Contact

Normally Open Contactr Normally Closed Contact

Continuity of ServiceContinuity of service is the state, qualityor ability to maintain continuous service.Examples are, maintaining electrical ser-vice without an outage or maintaining theoperating condition of equipment withoutdowntime.

Continuous CurrentThe continuous current rating of a circuitbreaker is a maximum rating and speci-fies the maximum current the device isdesigned to carry on a continuous basisand remain within the applicable guide-lines for that circuit breaker.

Continuous RatedContinuous rated is the ability to performa given function on a continuous basis,as opposed to intermittent rated. Switchcontacts, for example, frequently havecontinuous and/or intermittent ratings.

Control VoltageThe voltage, frequently secondary withrespect to a circuit breaker's operatingrating, used to operate secondary devicesand In secondary circuits. The voltageused to run a spring charging in a circuitbreaker's tripping system or to operatespace heaters in an enclosure areexamples.

Current Transformer

A current transformer steps current downto levels that can be used for a specificpurpose. See Section 5, page 20 andSection 7, page 40.

Curve Shaping

See Section 7, pages 40 through 43.

DC (Direct Current)

Direct current is current that flowscontinuously in one direction through aclosed circuit from a negative terminal toa positive (usually battery produced).

DE-ION Arc Extinguisher


Deionize

The process of removing conductingions, thus permitting arc extinction isdeionization. See DE-ION ArcExtinguisher.

Digital Device

See Section 5, page 20 and Section 7,page 45.

Din RailSee Section 14, page 135.

Distribution System

See Section 9, pages 74 and 75.

Downstream Device

In the context of a circuit, a devicebeyond a particular point in the circuitand farther away from the source is saidto be downstream from that point. If thedevice is closer to the source, it is saidto be upstream.

BREAKER BASICS 161

GLOSSARY

Dual Voltage Rating


Fixed Trip Unit


High Shock


Dynamic Impedance


Earth Leakage


Electrical Operator


Electromagnetics

See Electromagnetics discussion at theend of the Glossary.

Electromechanical Trip

See Section 5, pages 17 through 20 andSection 9. page 79.

Electronic Trip

See Section 5, pages 20 and 21, all ofSection 7 and Section 9, page 79.

Encased Circuit Breaker


Fault


Fault Incidence Zones


Fault Sources


Feeders

Feeders are comprised of the circuit con-ductors and components between themain and branch overcurrent protectivedevice. See Main and Branch Circuit.

Fixed Mounted Circuit Breaker

A fixed mounted circuit breaker is boltedinto a fixed position with bus or cablemechanically bolted to breakerterminations.

Flux-Transfer Shunt Trip


Frame


Frame RatingThe frame rating of a circuit breaker is themaximum continuous current rating for agiven frame size. See Frame.

Frequency


Front Removable Circuit Breaker

A front removable circuit breaker iscapable of being easily removed from astationary frame, with the bus connectionto the breaker termination by a manualcompression fitting. See Section 6,page 27.

Fully Rated SystemSee Section 8, page 65.

Grounded

When an electrical circuit is provided witha connection that gives that circuit adirect, positive path to ground, the circuitis said to be grounded.

Ground FaultSee Section 5, page 17.

Ground Fault Pickup and Delay


Handle Mechanism

See Section Section 6, page 29.

High Efficiency MotorSee Section 13, page 130.

IECInternational Electrotechnical Commission


12t Response

12t is a measure of the heatingiffect orthermal energy of a fault current. SeeSection 5, page 16 and Section 7, pages41 through 43.

InductanceInductance is a property of an electricalcircuit that tends to oppose any changein the magnitude of current through thecircuit due to the effect of CEMF. CEMFstands for counter electromotive force(back electromotive force) and is theresult of the expanding and collapsingmagnetic field around a conductor. Inother words, the CEMF works counterto the normal voltage.

Instantaneous

See Section 5, page 19 and Instan-taneous Pickup.

Instantaneous Pickup

See Section 5, page 22, Section 7, page41 and Instantaneous.

Integrated Rating

See Series-Combination.

Intentional Delay

An intentional delay with respect to a cir-cuit breaker's tripping action is a delaypurposefully added or introduced to thetripping circuit, so as to delay the trippingfunction for a set time, once the circuitbreaker is called upon to trip.

Interchangeable Trip Unit


162 BREAKER BASICS

/.=

Interlock DeviceSee Section 6, page 30.

Intermittent RatedSee Continuous Rated.

Interphase BarrierSee Section 6, page 28.

Interrupting CapacitySee Interrupting Rating.

Interrupting RatingThe interrupting rating is the maximumshort-circuit current that an overcurrentprotective device can safely interrupt.

Inverse TimeSee Section 5, page 18.

IonizedSee Deionize.

KeeperNutSee Section 6, page 27.

Key InterlockSee Interlock Device.

LEDUght emitting diode.

Let-Through CurrentLet-through current is the maximuminstantaneous or peak current whichpasses through a protective device.See Section 14, page 146 andSection 10, page 88.

Line and Load TerminalsSee Section 6, page 26.

Linear Current FlowUnear current flow is essentially currentflow in the same direction. See Section 5.page 15 and Section 12, page 106.

Load Center

A load center is an assembled piece ofequipment housing circuit breakers andconnections. It accepts an incomingpower connection and controls the powerdivision to branch circuits, while providingcircuit protection.

Locked Rotor Current

The locked rotor current of a motor is theamount of current drawn by that motor atthe very instant of start-up, when startingfrom full stop.

Long Time Pickup and Delay


Low Level Fault

A low level fault can range in magnitudefrom just above acceptable full load cur-rent to 10 or more times normal current.This type of fault does not usually causenoticeable damage immediately, but,undetected, will eventually lead todamage and/or equipment problems.

Magnetic Field Strength


Magnetic Flux


Magnetic-HydraulicSee Section 15, page 153.

Magnetic Only

See Motor Circuit Protector.

Magnetic Short-Circuit Protection --


Main

The main can refer to the circuit conduc-tors and components which supply anelectrical system between the main over-current device to the feeder overcurrentdevices. Main can also refer to the mainovercurrent device within the electricalsystem only. See Feeders and BranchCircuit.

Main ContactSee Section 5, page 15.

Manganin Shunt ElementSee Section 14, page 137.

MicrocomputerSee Section 7, page 45.

Microprocessor-basedSee Digital Device.

Miniature Circuit BreakerSee Section 15, page 152.

Molded Case Circuit BreakerSee Section 4, page 8.

Molded Case SwitchSee Section 14, page 150.

MonitorSee Current Transformer.

Motor Circuit Protector (MCP)See Section 13, page 124.

Motor Control CenterA motor control center is a piece of equip-ment that centralizes motor starters,associated equipment, bus and wiring inone continuous enclosed assembly.

Movable Primary ContactSee Section 12, page 107.

MultiplexedSee Section 7, page 45.

NECNational Electrical CodeThe National Electrical Code is a set ofelectrical installation standards applicablethroughout the United States and pub-lished by the National Fire ProtectionAssociation. The NEC works in conjunc-tion with UL requirements and usuallycarry mandatory compliance.

BREAKER BASICS 163

GLOSSARY

NEMANational Electrical ManufacturersAssociationNEMA is an association of electricalmanufacturers who establish manufactur-ing techniques and standards to meet therequirements of UL. These standards areintended to eliminate misunderstandingsbetween manufacturers and purchasers,and assist purchasers in the selectionprocess.

NEMA EnclosureSee Section 6, page 32.

Nuisance TrippingA nuisance trip is an unintentional trip atbelow set pickup currents, usually theresult of circuit conditions or equipmentapplications.

100% RatedSee Section 14, page 139 and StandardRated.

Operating MechanismSee Section 5, page 15.

OvercurrentAn overcurrent is a current that exceedsa continuous current rating and includesoverloads, short-circuits and groundfaults.

OverloadSee Section 5, page 16.

PanelboardA panelboard is a metal enclosedassembly designed for low voltage powerdistribution. It is available up to 600 voltsmaximum and utilizes bolt-on circuitbreakers.

Peak Current (Peak Value)Since alternating current varies con-tinuously from 0 to maximum to O, first inone direction and then in the other, it isnot readily apparent what the true valuereally is. The current at the top of thewave (maximum point) is the peakcurrent.See Section 5, page 20.

Pivoted Reverse LoopSee Section 12, page 107.

Plug-In AdapterSee Section 6, page 27.

Plug Nut


PoleSee Section 9, page 78.

Power Circuit BreakerSee Section 4, Page 8.

Power FactorSee Section 10, page 82.

Power GenerationSee Section 9, pages 74 and 75.

Power TransmissionSee Section 9, pages 74 and 75.

Printed Circuit BoardSee Section 7, page 44.

Push To TripSee Section 5, page 15.

Quick-Make, Quick-BreakSee Section 5, page 15.

Rating PlugSee Section 7, page 39 and CurrentTransformer.

Rear Connected StudSee Section 6, page 27.

Recognized Component (UR)See Section 4, page 10.

RepeatabilitySee Section 7, page 38.

ResistanceResistance is anything that restrictscurrent flow and is represented by theletter "R:"

Reverse Feed


Reverse Loop Contact


Root Mean Square Current (rms)

Root mean square current is also referredto as effective current and is the squareroot of the average of all the instantaneouscurrents (current at any point on a sinewave) squared. See Section 5, page 20.

Selectively Coordinated System


Selective Override Trip

This instantaneous trip function is set topickup and trip at the level of the shorttime rating of the breaker, and is suppliedon trip units without an adjustable instan-taneous trip function.

SelectivitySee Section 5, page 22.

Sensor

See Current Transformer.

Series-Combination


Series-Combination Rated System


Shock Out

Shock out is the unintentional mechanicaltrip of a circuit breaker. This phenomenoncan be the result of a number of thingsand can happen when the breaker is sit-ting in the closed position, or even whena breaker is being manually operated withthe operating handle.

164 BREAKER BASICS i

Short-Circuit


Short Time Pickup and Delay


Short Time Withstand Rating

The short time withstand rating of abreaker is the maximum value of currentthe breaker is designed to let through andhandle safely for a short period of time inthe closed position, without the contactswelding or any other type of damage.

Shunt Trip


Single Phasing

When one phase of a three phase systemopens, primary and/or secondary singlephasing occurs. Gone undetected orimproperly protected, this situation canresult in serious motor damage. Whenone phase opens, the current increasesin the remaining phases are dramaticbecause of the unbalanced overcurrentcondition.

Slash Voltage Rating

See Dual Voltage Rating.

Sliding Bar Interlock

See Interlock Device.

Slot MotorSee Section 14, pages 145 and 147.

Solenoid

A solenoid is a coil of insulated wire inwhich a magnetic field is established by aflow of current. Solenoids are often usedin combination with a metal core that isfree to move under the influence of themagnetic field.

Stationary Primary Contact


Switchboard

A switchboard is a metal enclosedassembly used for low voltage powerdistribution up to 600 volts AC, utilizing avariety of circuit breakers, switches andassociated equipment.

Symmetrical Current

A symmetrical current wave is symmetri-cal about the zero axis. This wave hasequal magnitudes above and below thezero axis. See Section 10, page 83.

Terminal Cover


Terminal End Cover


Terminal Shield


Thermal Magnetic Protection


Thermal Overload Protection

See Section 5, pages 16, 18 and 22.

Thermistor

A thermistor is a resistor made ofsemiconductors having resistance thatvaries rapidly and predictably withtemperature.

Time-Current Curve


Transient Inrush


Twisted Pair

A pair of shielded cables twisted togetherand used primarily for the purpose of car-rying Information is simply referred to as atwisted pair.

UL

Underwriters Laboratories, Inc.


Undervoltage Release (UVR)


Ungrounded

See Grounded.

Uninterruptible Power Supply (UPS)


Up-Over-Down Method


Upstream Device

See Downstream Device.

Utilization Equipment

When power reaches its destination andis distributed to equipment for use, to runa motor for example, the motor is theutilization equipment.

Voltage Rating


Walking Beam Interlock

See Interlock Device.

XIR Ratio


Zone Selective Interlocking


Standard RatedSee Section 14, page 139 and100% Rated.

Trip-FreeSee Section 5, page 15.

Trip UnitSee Section 5, page 16.

BREAKER BASICS 165

"t 1%

Westinghouse Non-Proprietary Class 3

LTR-NRC-06-47Attachment 2

Technical Data for AB DE-TON® Circuit Breakers

Page numbers included in Attachment 2 are as follows:AB DE-ION® Circuit Breakers, Pages 1, 2, 3, 4Molded Case Circuit Breakers Electrical Aftermarket Products and Services, Types EB and EHBMolded Case Circuit Breakers Electrical Aftermarket Products and Services, Types FB and HFBMolded Case Circuit Breakers Electrical Aftermarket Products and Services, Types EB, EHB, FB

and HFB -Accessories and ModificationsAB DE-ION® Circuit Breakers -Application DataAB DE-ION® Circuit Breakers - Dimension Sheet (2 pages)

Westinghouse Electric Company LLCP.O. Box 355

Pittsburgh, PA 15230-0355

© 2006 Westinghouse Electric Company LLCAll Rights Reserved

0 Westinghouse Electric CorporationDistribution and Control Business UnitElectrical Components DivisionPittsburgh, Pennsylvania, U.S.A. 15220

Application Data29-160

Page I

May, 1976Supersedes AD 29-160, pages 1-16 datedJanuary. 1971; pages 16.1-16.2 datedOctober, 1971; and pages 16.3-16.4 datedFebruary, 1973.Mailed to: E, D, C.'29-100A, 31-400A,

31-500A

Standard, SELTRONIC®, MARK 75@% andTRI-PACC) Designs AB De-ION"

Circuit Breakers

IndexDescription Page

Standard, SELTRONIC andMARK 75 Circuit BreakersGeneral information .............. 1Circuit breaker components andtheir function ................... IWestinghouse family of molded Icase circuit breakers .............. . 1-2Characteristic trip curves ........... 2Circuit breaker ratings ............. 3Underwriters' Laboratories test re-quirements ..................... 3Ratings chart ................... I 4Application information ............. 5

Circuit voltage ................ 5Circuit frequency .............. 6Continuous current rating ....... 5.6Unusual operating conditions .... 6Available short circuit current .... 6Field testing of molded casebreakers ..................... 16Molded case breakers forresistance welding circuits ....... 17,18%Duty cycle vs. during weld Iamperes ..................... 19

TRI-PAC breakersGeneral information............... 6Selection guide .................. 7Characteristic tripping curves ........ 7Basic application in distributionsystems ........................ 7Protection of connected apparatus ... 8Operating data .................. . 8

TablesTable A: AD breaker ratings formotor branch circuits ............. 9Table B: Motor terminal amperesat full load ...................... 9Table C. C-1: Motor application forfront-adjustable magnetic-onlycircuit breakers .................. 10.11Table D: Derating chart for non- Icompensated thermal magneticbreakers calibrated for 40C ........ -12Table E: Current limiting fuse ratings..' 13Table F: Allowable current-carryingcapacities of copper conductorsin amperes ..................... 15Table F.1: Correction factors, room Itemperatures over 30*C. 86'F2 ...... . 15Table G; Allowable current-carry-ing capacities of aluminum con-ductors in amperes ............... 15

Standard, SELTRONIC andMARK 75 Circuit Breakers

General Circuit Breaker InformationAD DE-ION molded case circuit breakers aredesigned to provide circuit protection forlow voltage distribution systems. They aredescribed by NEMA as, ..... a device forclosing and interrupting a circuit betweenseparable contacts under both normal andabnormal conditions," and further as,- .....a breaker assembled as an integral unit in asupporting and enclosing housing of insulat-ing material". The N.E.C. describes them as,"A device designed to open and close a cir-cuit by non-automatic means, and to open thecircuit automatically on a predeterminedoverload of current, without injury to itselfwhen propcrly applied within its rating."

So designed, AD DE-ION circuit breakersprotect conductors against overloads andconductors and connected apparatus, suchas motors and motor starters, against shortcircuits.

All Westinghouse molded case circuitbreakers are built to meet the requirements ofNEMA Standard AB-1-1975.

Circuit Breaker Components and TheirFunctionsBeing essentially a high interrupting capacityswitch with repetitive elements. AB DE-IONcircuit breakers are comprised of three mainfunctional components. These are: tripelements, operating mechanism and arcextinguishers.

Trip ElementsThe function of the trip element is to trip theoperating mechanism in the event of a pro-longed overload or short circuit current. Toaccomplish this, a thermal-magnetic tripaction is provided.

Standard BreakersThermal trip action is achieved through theuse of a bimetal heated by the load current.On a sustained overload, the bimetal willdeflect, causing the operating mechanism totrip. Because bimetals are responsive to theheat emitted by the current flow, they allowa long time delay on light overloads, yet theyhave a fast response on heavier overloads.

Magnetic trip action is achieved through theuse of an electro magnet in series with theload current. This provides an instantaneous

tripping action when the current reaches apredetermined value. Front adjustable mag-netic trip elements are supplied as standardon 225 amp frame breaker and above (ex-cept CA & DA) and on the 100 and 150 ampmagnetic only breakers, all other thermalmagnetic breakers have non-adjustable mag-netic trip elements.

SELTRONIC BreakersBoth the thermal type trip action and the mag-netic trip of SELTRONIC breakers are achievedby the use of current transformers and solidstate circuitry that monitors the current andinitiates tripping through a flux transfer shunttrip when an overload or short circuit ispresent.

All multiple pole circuit breakers have tripelements in each pole and a common tripbar. An abnormal circuit condition in anyone pole wilt cause all poles to open simul-taneously.

Operating MechanismThe function of the operating mechanism isto provide a means of opening and closingthe breaker contacts. All mechanisms are olthe quick-make, quick-break type and are"trip free." "Trip free" mechanisms are de-signed so that the contacts cannot be heldclosed against an abnormal circuit conditionand are sometimes referred to as an "overcenter toggle mechanism-. In addition to

* indicating whether the breaker is "on" or"off". the operating mechanism handle indi-cates when the breaker is "tripped" by movingto a position midway between the extremes.This distinct trip point is particularly advan-tageous where breakers are grouped, as inpanelboard applications, because it clearlyindicates the faulty circuit.

Arc ExtinguishersThe function of the DE-ION arc extinguisheris to confine, divide and extinguish the arcdrawn between opening breaker contacts.It consists of specially shaped steel gridsisolated from each other and supported byan Insulating housing. When the contacts arcopened, the arc drawn induces a magneticfield in the grids, which in turn draws the arcfrom the contacts and into the grids. The arcis thus split Into a series of smaller arcs and theheat generated is quickly dissipated throughthe metal. These two actions result in a rapidremoval of ions from the arc. which hastensdielectric build-up between the contacts andresults in rapid extinction of the arc.

t 1• ,

Page 2

U

Westinghouse Family of MoldedCase Circuit BreakersIn secondary distribution systems, there ae

many varied applications of molded case cir-

cuit breakers. To better cover this wide range

of applications, Westinghouse offers a family

of DE.ION circuit breakers within a given

frame size.

This family of breakers includes:

Thermal Magnetic (Std. and SELTRONIC)Magnetic Only (Std. and SELTRONIC)Ambient CompensatingSaf-T-Vue iMARK 75 (Sid. and SELTRONIC)TRI-PAC

Thermal Magnetic Circuit Breakers

Thermal magnetic breakers are general pur-

pose devices suitable for the majority ofbreaker applications and are considered theindustry standard. Combining thermal and

magnetic trip actions, they provide accur.

ate overload and short circuit protection for

conductors and connected apparatus.

Magnetic-Only Circuit BreakersMagnetic-only breakers are similar to stand-

ard thermal magnetic breakers except that

they do not have thermal trip elements. They

are equipped with front-adjustable magnetic

trip elements and are used where only short

circuit protection is required. Because the ad-justment feature allows closer short circuit

protection, these breakers are commonly pre-

ferred for motors and resistance weldercircuits.

Ambient Compensating Circuit

Breakers (Standard Breakers Only)Ambient compensating breakers are similar

to standard thermal magnetic breakers in thatthey are thermal magnetic and provide over-load and short circuit protection. The dif-

ference is that ambient compensating breakers

automatically compensate for variations in

ambient temperature. This provides a near -

constant current rating over a wide range of

temperatures. In effect, this breaker minimizes

the need for derating in higher ambients, and

uprating in lower ambients.

Because these breakers will carry their rated

current in higher ambients, circuit conductorsmust be sized accordingly. Generally, stand-

ard thermal magnetic breakers, which deratein about the same ratio as the average con-

ductor ratings, are best suited for conductor

protection.

Typical applications of ambient compen-

sating breakers include:

1. Conductors not subjected to same tem-

perature changes as the breaker.

a. Wiring located inside of a building hav-

ing temperature control, but the protectingbreaker mounted outside for convenience.

b. Wiring buried underground, but break-er exposed such as in some outdoor pumpcontroller applications.

2. Where overload protection of wiring is notof prime importance.

3. In portable engine generator sets, wherevaried climates and temperatures are en-countered and the generator is designedto the anticipated temperature extremes.

Because the above applications are inthe minority, ambient compensating isnotsuppliedas standardSELTRONIC breakers are insensitive to tem-perature changes. However, they include cir-cuitry to protect the components from ab-normally high temperatures.

Saf -T-Vuel" Circuit BreakersSaf-T-Vue breakers are similar to standardmolded case breakers except that they areequipped with a window of transparentthermoplastic over the breaker contacts. Thisallows you to see whether the contacts areopen or closed. These breakers fulfill theneeds of industrial plants where safety codesrequire visible contacts as an additionalsafety precaution for maintenance personnel.They can be supplied with thermal magnetic.magnetic- only or ambient compensating tripelements to cover a wide scope of appli-cations. They are not available in MARK 75or TRI-PAC breakers.

MARK 75 Circuit BreakersMARK 75 breakers are similar to standardmolded case breakers. They are, however,designed with increased interrupting capa-cities - up to 75,000 amperes asymmetricalat 240 volts Ac. The improved performancemakes these breakers Ideally suited for usein network systems and other applicationswhere unusually high fault currents exist.Standard MARK 75 breakers are equippedwith thermal magnetic trip actions. Mag-netic-only and ambient compensatingO tripelements are also available. MARK 75 mold-ed cases are of a gray polyester material whicheasily distinguishes them from standardbreakers, which are black.

TRI-PAC Circuit BreakersTRI-PAC circuit breakers offer an evenhigher interrupting capacity than MARK 75breakers. They are similar to standard ther-mal magnetic breakers except that they incor-porate a current limiting device. This enablesthem to be used in secondary distirbutionsystems where fault currents up to 200,000symmetrical rms, amperes are available. Thus,as their name implies, they are a triple packageof protection - (1) time delay thermal trip foroverload protection, (2) instantaneous mag-netic trip for normal fault current protection,and (3) current limiting action for higherfault current protection - combined andcoordinated in a single compact and econom-

icat device. Because they limit current, TRI-

PAC breakers can be used to protect smaller

AB breakers and other connected apparatus

in addition to protecting feeder and branch

circuits. More specific information on TRI-

PAC breakers is contained elsewhere in this

publication.

Characteristic Trip Curves (Except

TRI-PAC)Characteristic trip curves are found in Appli-

cation Data 29-161 AWE Awhich is avail-

able on request.

The band curves shown for each breakertype represent current tripping limits for the

breaker and are within limits established by

the Underwriters* Laboratories. For a givencurrent, at rated ambient, a breaker will clear

the circuit automatically at some total time

within the two extreme values defined by1'maximum" and "minimum" curves, For

example, a 1 pole. 15 ampere Quicklag would

trip in not less than 10 seconds and in not

more than 150 seconds on a 30 ampere cur-

rent. Because of this allowed spread, users

should not specify exact tripping times.

The upper left portions of these curves show

the inverse time delay tripping of the breakersdue to thermal action. The lower right seg-

ments of these curves portray the magnetic

tripping action of the breakers. In the case of

the front adjustable thermal-magnetic break-ers. the magnetic tripping elements may be

adjusted to trip at values within a specificcurrent range. This adjustment is shown on

their respective characteristic tripping curves.When these breakers leave the factory their

magnetic trip elements are set at the high side

of their tripping range. Adjustment downward

may be made to fit the requirements of theinstallation. Currents equal to or greater thanthese magnetic settings will cause instanttripping. Curves shown are family curves andare suitable for most applications; for more

accurate application, a detailed curve of the

particular type and ampere rating of thebreaker should be requested.

The total time taken by a breaker to clear a

fault consists of the mechanical operating time

plus the time of actual current interruption.Characteristic family curves show total clear-

ing times. Magnetic only breakers have no

time delay in tripping. The tripping character-istics of these breakers are similar to the right

hand portion of the standard breakers, except

with the vertical lines extended to the top of

the curve.

Circuit Breaker RatingsA circuit breaker is rated in rms amperes. (at a

specific ambient) voltage, frequency (usually

60 hertz), and Interrupting capacity (in rms

symmetrical and assymmetrical amperes).AB De-ion circuit breakers listed in the 29.000section of the Westinghouse catalog are rated

Q> Lxceot If(, SEt TrRONIC I)a'.l;s,

I

f' ,. 14

I0 Application Data

29-160

Page 3

a maximum of 3000 amperes continuous and600 volts Ac, 250 volts Dc. For a summary listof ratings, voltages and interrupting capacities,see selection chart on page 4.

Circuit breakers are not horsepowerrated.Unlike switches, circuit breakers are not horse.power rated because they are able to safelyinterrupt currents far in excess of the lockedrotor value for any motor with which they maybe applied. This ability is recognized in theN.E.C. as stated in paragraph 430-109, and isproven by the Underwriters' tests described inUIL Bulletin number 489, "Standard forBranch Circuit and Service Circuit Breakers".

For example, a breaker must pass the U/Loverload test consisting of breaking a current600% of its ampere ratings. As motor branchcircuit breaker ratings are usually 125% to250% of motor full -load currents, this testestablishes the ability of the breaker to morethan interrupt locked rotor currents. Followingthe overload test and others, the breaker iscalled upon to successfully clear its rated shortcircuit current which is a minimum of 5000amperes. This also is many times higher thanmotor locked rotor current. Because by defini-tion a circuit breaker is required to "openunder abnormal conditions...without injury toitself", the breaker must still be in operatingcondition after the test.

Underwriters' Laboratories TestRequirements

Standard Tests1. The tripping mechanism shall be enclosedto prevent tampering.

2. The mechanism shall trip free of the handleon overload.

3. All breakers shall be calibrated to carrytheir continuous rating in an ambient tempera-ture of 40'C.0

4. 200% calibration check.

5. 135% calibratiof check.

6. Overload tests at 600% normal current atrated voltage.

Up to 1600 Amperes: 50 operations2000, 2500 Amperes: 25 operations3000. 4000 Amperes: Three operations at600% followed by 25 operations at 200%.

7. Temperature rise check at 100% rated loadcontinuously without exceeding specifiedtemperature limits.

8. Endurance test:Ampere OperationsRating rull No Per

Load Load Minute

10. It must next pass short circuit tests at itsrated voltage at the value shown in the follow-ing chart.

Breaker Rating Test Circuit For ThreePole BreakersIndi. Common Totalvidual Poles No. ofPoles Amps TestsAmpsVolts Amps

250 & Below 100 & BelowAbeve 250 100 & BelowAny 101-. 800Any 801-1200Any 1201 -1600Any 1601 -2000Any 2001 -2500Any 2501 - 3000Any 3001 -4000

4,330 5.0008,660 10.0008,660 10.000

12.120 14.00014,000 20.00014.000 25.00020.000 30.00025,000 35,00030.000 45.000

777788888

0- 100101- 225226- 600601 .- 800801 - 2500

2501-4000

600040001000500500400

400040005000300020001100

654

11. After the short circuit test, the breakermust again pass a calibration test at 200% ofits rating.

12. Successful breakers passing all of theabove tests must then pass a dielectric with-stand for one minute without breakdown. Thetest consists of a 60 hertz potential of 1000volts plus twice the rated voltage between lineand load terminals with the breaker open andin the "tripped- position, between terminals ofopposite polarity with the breaker closed andbetween live parts and the enclosure with thebreaker open and closed.

13. A sample lot of breakers, as defined byU.L., INC.. must pass the above sequence oftests without failure to achieve the initialstandard U.L. listing. Once standard listing isachieved then higher interrupting ratings maybe obtained by submitting sample lots ofbreakers to additional interrupting tests con-ducted for the particular rating desired. Theseadditional tests will be conducted in accor-dance with the following sequence:

High Interrupting Capacity Tests1. 200% Calibration Check.

2. Short circuit interruption. Two three-phasetests, one "open" followed by a "close-open"at the desired rating.

3. 250% Calibration check.

4. Finally, a dielectric withstand similiar to theone described above must be passed. Thevoltage for this test is twice rated but not lessthan 900 volts.

9. After endurance test. the breaker mustagain pass a calibration test at the 200% and135% ratings.

(D Additional tests as an enclosed device reouired lotlisting as 100% application device.

Pagje 4

AB DE-IONR Circuit Breaker Interrupting RatingsCircuit Breaker RatingsType Cent

Amp.Rating

No.Poles

fed Spec. U.L. Listed interrupting Capacihies-RMS Symnietrical AmpsVolts W.C.375a Ac Rating Volts Dc Rating Volts(S)Ac Clas.s 1"20/240.. 24" 0 277 .. 480 600 " 125 -" 250

ILighting Circuit BreakersOC. HOP. BAB 10.7

15-1HGC. HONP. BA 15-5

15-.1

BA 15-3.OHP. OHC, HBA 15-34

15-24QPGF. QBGF 15-.3OPHGF, QBHGF 15-3OPH.OCH.OBH 15.7

15.115.?'

0250000000000000

12i -3

1-23

1.21123

2.32-32-3

120/240120/240

240240277

120/240240

120/240120/240120/240120/240

240240240240

Ia 10.000 ...... ...... ...... ...... ...... ......la 10,000 ...... ...... ...... ...... ...... ......l b ...... 10.000 ...... ...... ...... ...... ......11b. . . .- ... ... . T•.-000 -- ......- ...... .. :.... . ... .. .. ......2a ...... .... 10.000 ...... ..... ...... ......"• -5 .•3 - . _.._ .... . . ... .. .. ...... ......56.. _, ...... ... .... . ...... ......

• '"1 .0.0o ...... ...... ...... ...... ...... ......

22.000 ........ ...... ...... ...... ......22.000 ...... ...... ...... ...... ...... ......22.000 ...... ............ 22 00 :'* I . ":.0. ... ....... ...... ......."0..... 1 0, ...... ...... ...... ...... ......

22.000: - . ..:2 2... 0 0.. . . . . .. . ... . . . . . . -. . .. . . . . . .. .. . . . .

Q)...... 22,000 ...... ...... ...... ...... 10,000(4)

CA 125-225CAM 125-225QA 256.400

Industrial Circuit Breakers

EB Standard 15-100 1 120 2b 10.000(i) ....... ....... ....... ...... 5.00015-100 2.3 240 2c ....... 10.000 ...... ....... . ......... .. 000(2)

EHB Standard 15-100 1 277 2a ...... " 14.000 ....... ...... 10.00015.100 2 400 2d ...... 18,00 ...... 14.000 ....... ........ '.1 o0"15-100 3 480 2d ...... 18.000 ...... 14.000 ..... ..... ......

F8(3) Standard 15.150 2 600 2d 1....... "8,000 .....00 14,000 14.000 ..... 10.00015.150 3 600 2d ..... 18.000... 14,000 14,000

J.-KB Standard 70.250 2 600 3b ...... 25.000 ...... 22.000 22.000 ..... 10.00070.250 3 600 3b 25.000 ...... 22.000 22.000 ..... ......

LB-LB Standard 7b.400 2 600 4b ...... 42. 000 30.000 22,000 -.... 10,00070-400 3 600 4b ... :. 42.000 ...... 30,000 22.000 ..... .....

LA Standaid 250-600 2 600 4b ...... 42.000 ...... - 36.000 22:.60 10.000250-600 3 600 4b ...... 42,000 ...... 30.000 22000 ..........

LC Selrtontc 75-600 2.3 0'6-0 4b 42.000 .... 30,000 22,000 ""MC Seltronic 400-800 2-3 606 5a 42.0 . .... 30. 000 i2,060 .......2.....NC Seltronmc 600-1200 2-3 600- 42000 30,000 22000 ...... ......

PC Sel,,oic 000.3000 2-3 600 -_ 25.000 _...... "o0oo•- 10o0oo .... ..PCC(6) Sollronic 1000.3000 2.3 600 ) 125,000 ..... 00.000 100,000 ...... ......

High Inlerrupting Capacity Circuit Breakers

HFB Mark 75 15.30 1 277 (2) ...... ...... 65.000 ....... ...... 10,000 ......40-100 1 277 0 ...... ...... 25,000 ....... ...... 10.00015.150 2 600 21 65.000 .25.000 18.000 .. 0.00015.150 3 600 21 ..... 65,000 25,000 18.000 ......

MVKS Mark 75 70-250 2 600 ...... 6K.6000 .. 25.000 22" 10.00070.250 3 600 0. 65,000_.... . 25.000 22.000 ......

IIL0 Mok 75 125-400 2 600 .... 4c 66.000 ..... 35.0•00 25.000 10.000125•400 3 600 4c ..... 65.000 ...... 35,000 25,000 ......

HLA Mark 75 250-600 2 - 600 4c ... 65,.000 '.... 35,000 25.0001." 10.000250.600 3 600 4c .. ... .. 5.0o ..... . 35.000 25.000 ......

HLC Mark 75 75-600 2.3 600 . .... ...... ,....... 65.00.0... ..... 35.00 - - 25.000 ",.

HMC Mark 75 400-800 2 - 600 5b ..... 65.000....... ..... 50,000 25,000 ...... ......400.800 3 600 5b ........ 65.000. ...... 50,000 25.000 ...... ......

HNC Mark 75 600-1200 2.3 b S 65.000 5.000 ......I8 ,,Pac 15-100 2-3 600 ...... 200.000 200. 200.000 ..LA Tr,.Pac 70.40o 2.3 600 3c/4a _ 20.000o ?00,000. 200.000 ...... 0)NS Tri.Pac 300-800 2.3 60 " - ...... 200.00 -......... 20000.o '. 200.000........ .......

PB Tri-PaC 600.1600 2.3" 606 - ) 200,000 . 200.000 200000

IF

0)120 volt only.() 125/250 Volts Dc only.03 Available in 4 pole verion.@ 2 pole only.0) Higher NEMA ratings available.() U.L. listed at 100% rating.() Not defined in W.C-375a.(1) 100.000 based on NEMA test ptrcedurp.

'( I . %.

Types EB and EHB

Replacement Capabilities Table 3-12. Type EB 1-, 2-, 3-Poles; 240 Vac Maximum; Thermal Magnetic and Saf-T-Vue'M'ýZ•i Shaded gray area denotes obsolete or discontinued products and services. '

Continuous 1-Pole 120 Vac, 2-Pole, 240 Vac, 3-Pole. 240 Vac.Ampere 125/Ve'• 15250 Vdc 0, 125/250 Vdc o)Rating Standard Standard Standard Saf-T-Vue k"

at 401C

EB: 120,240 Vac; 125/250 Vdc

Q) These frames are obsolete. For replacement solutions see the cross-reference on Pages 3-97- 3-118.- dc ratings apply to substantially non-inductive circuits.T'? Not UL listed.ft' Switching duty rated for 120 Vac fluorescent light applications only.Note: Includes Load Terminals Only.

EHB: 277, 480 Vac; 250 Vdc

Table 3-13. Type EHB 1-, 2-, 3-Poles; 480 Vac Maximum; Thermal Magnetic and Saf-T-VueV':rJ Shaded gray area denotes obsolete or discontinued products and services. ODContinuous 1-Pole, 277 Vac, 2-Pole, 480 Vac, 3-PoleAmpere 121dc(• 250 Vdc 4•: 480 VacRating Standard Standard Standard [Sa-T.Vue cr:

at 40°C I NCatalog NumberI

A) These frames are obsolete. For replacement solutions see the cross-reference on Pages 3-97 - 3-118.1'-9 dc ratings apply to substantially non-inductive circuits.Q'; Not UL listed.(: Switching duty rated for 277 Vac fluorescent light applications only.Note: Includes Load Terminals Only.

Table 3-14. UL Listed Interrupting Ratings •I Maximum Volts AmperesES Breakers120 and 240 ac 10,000 Asymmetrical. Symmetrical125/250dc 5,0000

EHB, FB Breakers240 ac 20,000 Asymmetrical, 18,000 Symmetrical277 ac (EHB) 15,000 Asymmetrical. 14,000 Symmetrical480 ac 15,000 Asymmetrical, 14,000 Symmetrical600 ac (fF8 15,000 Asymmetrical, 14,000 Symmetrical250 dc 10.000 $,

0,) Interrupting capacities shown do not apply to molded case switches.0 dc ratings apply to substantially non-inductive circuits.

'e -'' ý

Types FB and ItFB

Replacement Capabilities Table 3-15.Type FB, HFB 1-,2-,3-, 4-Poles; 600 Vac Max. Thermal Magnetic MARK 75' Sat-T-VueMUM, Shaded gray area denotes obsolete or discontinued products and services. co'

FB, HFB: 600 Vac; 250 Vdc

Contin- 1.Pole 2-Pole 3-Pole 4-Pole 0',Duous 277 Vac 600 Vac 600 Vac 600 VacAmpere 125 Vdc (1, 250 Vdc 0;Rating MARK75:i) Standard MARK 750 ; Standard I Sat-T-Vue 'i MARK 75 0 Standardat 40" Catalog Number

i.5;,,•;HFB101.A F82015-?" FFB2015: 3015) FB3015S;.'X1.,I HFB3015L FB40!,•5! <; -F131025 , . F02025 ? HF92025 PB3025•• FB302S ' HFB3020L P84025

,•0:,-:HFB03 FB2oOS-IFB2O5O•'•• P'B3O3: FB3OOS 2 HFB3025L IB4050•352•

14,FS

10 3O;., FB2035 .:,HFB2O65• PB3060", F306Sý4-• HFB3030L IP84065

HF8045~~F82035, f tPB205 '.Pd5S HFB3035L 845

0., Po. U listedFB3040L f40

or0m ;iesoa diffeences

80.15 -O 30A rated 5,000 AC ý.' HF83045L FB40 4 4

480F - 1 FB100ted 30,0s0iP HFB2OBO. A FBsymetrSMcl HF83050L~ H~B~~o P9290., HF90S0vF ,og0j 39S:~ HFB30160LP904

Pe~i~o~C<HF83070L~

25,00000 I symetrcal

i.O V•.FIO0" YFB?2t F82 T8309 f8~0S~IB10 F~

@ Thluese frames are obsoleteFrreplace.Ment so lutonse Sorhane ross-efrenc to Plages 3-9 m-3-118"') dSwrtcings apply rteforsubs7antiallyononcinducivet cppircuits. sony

Ta5l Not6. UL. listed

or daimunsionlt differen res.

MAR j 5 Typ FFFBFB124 15-30 Ac rated 75,00A 0 SC

40-10 Ac rate30, 000A Asymmetrical. 500Symtia25,00 Ac symmetrical.l,2500Smmtrca

600-pl rekr are suplie iny 3plfrmesWthial curr0 yentcrringcartl mte rmcne oe

W0 cdese lne ane loadleterminal. MArK 75pframetoltors ehaed frosmrfray on back in m-2002.

f?) Swirtcings dutly rtefor7 susactal flninuoectight acpircaitios.nyTale 3N6. UL listed Itrutn aig .

MadimumsVonlt Amperen es.MARK30 ratyed 7500 B240 ac 75,Arte3, 000 A asymmetrical, 6,0ymtia40a3000Aymtia,25,000 S ymmetrical.

M Swachigdt ae o 277 acfloresmentrlcgtappl8i0caSmmtricaoly

250:dc (3Ple 0,000 Asmeria,2,00Smmtia

('; Interrupting capacities shown do not apply to molded case switches.0 15 - 30 A rated 75,000 AIC.

40 - 100 A rated 30,000 A asymmetrical,25,000 A symmetrical.

O dc ratings apply to substantially non-Inductive circuits.O Ratings above 10,000 amperes not UL listed.

Table 3-17. Special Breakers Type FB, Magnetic Only, Front AdjustableWma, Shaded gray area denotes obsolete or discontinued products and services. 0

Continuous Magnetic 2-Pole, 600 Vac 3-Pole. 600 VacAmpere Trip Range Standard I MARK 75 1 Standard I Saf-T-Vue MARK 750Rating JAmperes I CataloglStyle Number

Nt.4L '4 7221,ý"'P8 F2022tvRLU. .HF132022MUL,` FB33221VRLq FB30O22SMRQ H-F83022ML, ~:,05RL F245,BP3045'MR',IA F!• F "30645SMRkL•.' HFB3045ML

•. ..... .... ..

FRT1210VIMF• Pc 210M" F8311OMRLW, ý.131pSMRVL4 HFB3110MLThese frames obsolete12ý 2611D53 3O; 4sabs 2610057G30

1`29ue4" -!W t 190MRnls. MAK 5 rameL Fc3l1o0rc Me from1gSMRayLto HFB319oML

II0 27. FU270M~k Ž, "F62276MQý? ýB20~~~37SRt,, HFB3270ML

d020 61MD53G1E32480M4D6G3 FB4 WE' MR HF83480ML1603G , 4_)61ý IO.5GW1 2605G 4994096G31

00 0~40~ ~81.6 )2.81G4 81f 4O47l 65E4667

~~00~~~4~WO .......O; ...50R)FBISSJL HFB3155OML48 These frames are obsolete." Includes line and load terminals. MARK 75 frame color changed from gray to black In mId-2002.

-'. t . 11

Types EB, EHB, FB and HFB -Accessories and Modifications

Replacement Capabilities (Continued)

Accessories and Modifications

timni Shaded gray area denotes obsoleteor discontinued products and services.

TerminalsBreakers include load terminals only.Terminals are Underwriters Laborato-ries listed as suitable for wire typeand size. When used with aluminumconductors, use joint compound.When line terminals are required,order by style number from thetable at no charge with the breaker.

Note: Magnetic only breakers include bothline and load terminals.Note: Suffix 'L" on catalog number Indicatesline and load terminals included. If factoryinstallation is required, specify on order.

Table 3-18. Terminals

Maximum Wire Wire Package ofAmperes Type Range InThree Line

TLerminals (0iJ Style Number

Standard Pressure Type Terminals

20(EB,EHB) AI/Cu #14-0101 624B100G14100 AI/Cu 014-1/0 624B10OG02150 AI/Cu 11 4-4/0 624B100G17

0°C Cnalibration a

Add suffix "Vp to catalog numberfor complete breaker, listed abovewhen ordering breakers to be usedin 50°C ambients.

Note: Not UL listed.

Optional Al/Cu Pressure Terminals

o0 Al/Cu #14-#4 1624BI00GoI100 AlCu # 4-410 624B100G17

ý,) Style listed is for package of three terminals.

IF-Screw

Conductori*

Wire Clamp

Style 624B100G14Assemble wire clampto bottom of conductoras shown.

Style 624B100G02Insert collar enclosingconductor as shown.Locate nut on top ofconductor and tightensecurely with screwand washer. Caution:Collar must surroundconductor.

Style 624B100G10Assemble collar ontop of conductoras shown. Tightensecurely with screwand washer.

Style 624B100G17 -Insert collar enclosingconductor and centeron extrusion on collar.Install clip with legson top of conductorand snap end aroundbottom of collar.

Fedih~era fmaltminCelicateionker A

iraIp~~fO amperes.,Factory'ý

Federal Specification ClassificationsEB, EHB, FB and HFB breakers meetrequirements of Federal SpecificationW-C-375b as follows:

a EB: 1-pole, Class Ila; 2-, 3-poles,Classes 10b, 11b, 12b.

a EHB: 1-pole, Class 13a; 2-, 3-poles.Class 13b.

* FB: 2-, 3-poles, Class 18a;* HFB: 1-pole, Class 13a; 2-. 3-poles,

Class 22a.

Figure 3-2. Terminals

MU3 Shaded gray area denotes obsoleteor discontinued products and services.

!-Tbh 6FB Curr~hCLimjter~i~itan'ac

a staindard FB4 r)'

2ý00 000;Affril~e upji~Api3

~thdaeLF8 emnl r suitabl

'a #1_415 -a 410

Table 3-19. LFB Current Limiter Attachment,Z.=', Shaded gray area denotes obsoleteor discontinued products and services.o)

Arnp~res~' J Ctaten Numbr 'h'4

15- 70<.~Ai~.%As! LFB3O7OR ~ 51

~'~i M nn'.etii~ flinty flr&al~ai~ ~'.~5" ~

'I 3O3?t"" L900 7 5,57

ý100 L 0'I0'0M'

V) These frames are obsolete. For replacementsolutions see the cross-reference onPages 3-97 - 3-118.

(3) Ratings through 70 amperes can be suppliedwith terminals for Cu cable only (914 - 02).Order by description.

(t) Superseded by LFD307OR.It) Superseded by LFD3150R.•; Replace with Series C HMCP and ELC

current limiters or replace with MCP and ELCurrent limiters.

,A I a

Application Data

AB DE-ION Circuit BreakersTypes EB, EHB, FB; MARK 75 Type HFB; 50-70 Amperes, 2, 3 Poles

€v80.'4t : 3 1 .80 1 ? I Fo RT § I §I

it a I - evr 1 33 *C~ 1i 9 . .II . VV 2943

I Iii i t -4-1 i4 00

P _H- Mi i-

If -- I I IIII I

43.

Circuit arevi..r Yiv,.C-r~rvv Curves

Top. &W01. vx!8 - 4. W0 .... 0. vi v.. 8,10d3s W

FW.. 00.i4;M .v4dv3v o... 0- .I .Nw. Or..dO 4

a .. Cv. V.C.t'ý

8,.a~ce vyovo. 0 V.0

W ~Ivv NO , IL io f810 1240ws AM2344330A:il j.i l~a11 a . 2

- a

\\' '3ouv SIn iv '1

921 0lCIo rolerues at 25,01f,

go 300 4.8 14 08 20.08

a.iy3 Ace ..mrv o I"43. C. 34 . 3

E

MinimuMximum

.• ~Ma-urnm Interruplln? Time 6I I I I Il 1l1l

it le rup lr'n Rating {$i Tobv latiO a Abov e

7e

l~I T'

., ~ ~ ~ ~ ~ ~ -w 4ýi!'ii,:•! '•i

aA

hI!~I X il 4 41- K .Curve No. SC-3510-77

October 1997

1**0 -*

Dimension Sheet

Types EB, EHB, FB, MARK 75, HFB

Outline DimensionsDrilling Plans

AB DE-ION®Circuit Breakers

Types EB• EHB, FB, MARK 75 HFB 1-, 2-, 3-, 4-Pole Thermal Magnetic Breakers (See Note Below)

SOfe.T-Voe Coov., When l•ulododl - 5-1/2

n ..... F r4-1 . . TID-am: Tte 1R3ol 51Line End so-a-.4---.ol\ 1 L.... o1 : l0/•moerHol, s/1lDoop

.Vý4.1 O[SZ0OL 11/64 -L. io-1/161/ 1011116 *5.1X44-,., Load End _.-24.,,,0 -IS ''8 I

3/16Olameter H~ole 11/32 DimeterCounlorbom 114 Deep opom Top.11132 D;-meter Covnterbo,# 21/32 D* ol Bom, ttom

2- and 3-Pole FB and HFB Magnetic Only BreakersCurrent carrying parts are omitted from center pole for 2-pole breakers.

V -1-8-, -- ,12

I / 18i 40roh P/ol ep Line EndLine End , - V2 A.c" pti 6- Thread Cvtli-g Scrow

r= 1717nSAfT.Voco(M•,ln Irluld

Tripped 3-30"

T, 1e d-1

. ••Of!

516 .. 7*Toper Each Sldo

1/64- • -. ' 4 -1/1 1•& 14"-t°/5-* oa nLoadEndd

-- c! -I -I1/2 Inc h 6*/de Conp, :tnorlwith 7132 Diameter Hole

2116 Dion•ler Hole 11132 V/anAle, Co MnapIlore I f t Door hora lop.1 U32 Dametetr Coontobor. 2•132 Deop froom etoon 5-3/S --

r 2.21l2Z~~1' ~.~~~ I•-- 3-3113 -- •' 7o'1/2 "

Note: MARK 75 HFB Thermal Magnetic Breakers Support Blocks for Line and Load Ends are not Supplied with Breaker and Must be Ordered Separately.Two-pole breakers are furnished In three-pole frame Refer to Drawing 506C144 When Ordering Support Blocks. All Parts Necessary to Convert a Standardwith current carrying parts omitted from center pole. Breaker are Included.

Plug-in and Bolt-on Detail

Support Stab Breaker Plug-in Bolt-onB Bolt stab to breaker Bolt stab to support

Conductor conductor, then plug block, then bolt supportinto support block, block assembly to

breaker conductors.

d I . :,

Dimension Sheet

Drilling Plans for Types EB, EHB, FB, MARK 75 Type HFB Breaker

Drilling Plans 1., 2- and 3-Pole2-Pole MARK 75 and 2-Pole Magnetic Only Use 3-Pole DrillingFor Mounting Bolts

.194-32 Topped Holes Line End

3-Pole 2-Poe [ I-Pole 4-t/2

IV1'--i::i- _ Load End I-- 1V1/16O----- -1.3/8 Front VtwF 1-..t- --

For Rear Connected Studs

3-Pole Iffa elm 2-Pol 1 ,rh. I -Pote Il 5-1,1

wnol IV - -I .... 3l' 't -'- i,,.,T l I'•.... -~ -

"--18~~oiim 1/32 Load End

Plug-in Block15 to 150 Amp 2-Pole Breakers 15 to 150 Amp 3-Pole Breakers, 2-Pol(Thermal Magnetic) Magnetic Only and MARK 75 Breakei

Drilling Plans 4-Pole

For Mounting Bolts For Rear Connected Studs

tine End Line End

M h s -7116 Dlanmeler Holeso - - -IIo(Lo ee IS"-- toriSto 10Amp

me.hatgn 4I/ 'a'... I ' .. o•O•jErtr 4 T o ;w3 for 125 o150 IOAnrp8qae--r f tI-,8J trie.'

Handle HOndao O~3,e, LJ_ .....164-32 l Load End Load End

Ho.le -2,3/4-1 PF,o.nVie,,. 1.318 (PFo., VoeW,

Terminal Arrangements

Romovable Conneclor UL Listed Wiro Connetctor Available Contact SurfaceRange e14 to 10 Cu 012 to 1/0 At Strip 11518 Line End - 19/32 Load Endwil Accomnmodar 914 to 310 Wiee

Wire Connection Bus Connection Stud Connection

Rear Connected Studs (Not Supplied With Breaker)

Meacing Monlngel

Surface

.14 IEDp= rnN==... . C.. . .. .. . j

lers

Un. End 1/311it-7% t

... 31101w21M2 Radius ,. -

7tl 6 la 121Hote[4:-1l21/32Radios. l-J 1 Fla

13/16

Load End In2 v4 I of Brooks,

Line End 1/21/4-"-1-3•S ':1316

7 i2) Holes- -111/1

Load End I2 1t4 (of Beaker

1-, 2- and 3-Pole 3-34Line Endr•.r-11V1 . 1/4 RadiusCutout frot [ 11 "T 1t -t 9/2.

S5I-T.Vua Cover F1 7

1Whe ..... 0r.-.-I ...-.- "- • -

7132 Sadionu 1 2? 32" " 2 21132

V3 A I -38 . .... 2.5/32

For 2-Pole Broeketr I ....

i_."T-- Nt J...... Load EndFor Single Pole Breaker Omil 2 Holes 5110 Diarneler Megger Holes

7132 Radius .ý4 a.'-3112

Line.EndI I 2-1/16• III. .* 1.. •or

6/10 Dsiene, 27/32. [ BreekerMeoggr Holes 2-5/32 Haond1

Load End 13/

Stud IStud Pne Tub Tub 0D E16Ampere Style' ýT~llckne ent StyleRtating INubrn A Number

For 15 to 100 Amp Breakers

180 AShort 4510874001 1 1-1(10 r 22544C1-20 1,=OShort 4510874G01 I11115to 15116 1-3/B5 3289446H I2

tA Short 4510874G1 3ABIo SSB 1-11116 I 32B944tl-22 6-W/S 3-S/S 516-1B00 A Short 451C08741081 1/4 105/16 2 I 32B9446H23

1100A Long 45108741302 1 3-7/16 3209446H424100A Long 4510574002 11V16tlo51S "44 3289446H25 j100 A Long 4510874Gt2 2/810 U/S j4-1116 32694461426100 A Long 4510874002 1/4 to 6/16 .440 32289446H427

For 125 to 150 Amp Breakersi50AShon 2740883001 I 1-VIlS 374018831106ISOAShort 374D832G01 V /6 to 15116 1-3MS 37408831-107iSOAShort 3740883001 3/8 to 8 1-I1/1 3740882148 7-1/2 4-1/4 7/16-14150 A Song 3740882082 1/416 o51518 12 / 274088314111l0 A Long 274O803001 1/43-7/16 2374D883H40150A Long 3740883G02 11/6t ~M 3-7/2 37408831 1150 A Long 3740882002 3M/to0 5/ 4-1116 3740883141150A Long 2740883002 1/4105116 4-38

Front Cover Cutout4-Pole

Ordering instructions: Stud complete consists of one stud assembly and one tube as perchart. Order long and short studs and tubes as required to obtain proper but spacing.

Documents

Westinghouse Motor Control Center (MCC) Breakers. · Westinghouse has been the world leader in molded case circuit breaker technology since inventing the DE.IONe arc extin-guisher