Protection Coordination Tabels

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Selective CoordinationBy: Charles J. Nochumson,

National Application Engineer

Eatons electrical business

Phoenix, AZ, USA.

Eaton Electrical Inc.

1000 Cherrington Parkway

Moon Township, PA 15108

United States

tel: 1-800-525-2000

www.EatonElectrical.comCo-author: Kevin J. Lippert

Manager of Codes & Standards

Eatons electrical business

Pittsburgh, PA USA.

Selective Coordination

Abstract

In the design of Elevator feeders, Emergency Systems, LegallyRequired Standby Systems, and the essential portion of Healthcareelectrical systems, todays engineer faces greater difficulty in meet-ing the 2005 NEC Selective Coordination requirements. Whetherutilizing breakers or fuses, the engineer has to understand the natureof the devices being selected, and properly apply them, such thatonly the protective device nearest to the fault will open to clearan overload/fault condition. This paper will briefly cover the NECrequirements regarding selective coordination. A review of short-timeratings and how they affect selective coordination will be discussed,along with an appendix regarding X/R ratios for low-voltage circuitbreakers. This article will then discuss some techniques for selectinglow-voltage circuit breaker protective devices to provide selectivecoordination.

I

. 2005 NEC REQUIREMENTS

The 2005 National Electrical Code

1 (NEC) has added specificrequirements for designing a system with selective coordination.Coordination (Selective) was added to Article 100 Definitions asfollows: Localization of an overcurrent condition to restrict outagesto the circuit or equipment affected, accomplished by the choiceof overcurrent protective devices and their ratings or settings.Since the choice of the overcurrent protective device, togetherwith their ratings or settings, is a task of the design professional,a better understanding of the options and choices is required.

In past issues of the NEC, only Article 620.62 (Elevators, Dumbwait-ers, Escalators, Moving Walks, Wheelchair Lifts, and Stairway Chair

Lifts) had a specific requirement for selective coordination, and thedefinition appeared in Article 240.2. Article 620.62, Selective Coordi-nation continues to require Where more than one driving machinedisconnecting means is supplied by a single feeder, the overcurrentprotective devices in each disconnecting means shall be selectivelycoordinated with any other supply side overcurrent protectivedevice. The 2005 NEC has now added a similar requirement underArticle 700.27, Coordination, Emergency system(s) overcurrentdevices shall be selectively coordinated with all supply side overcur-rent protective devices. Also Article 701.18, Coordination addedLegally required standby system(s) overcurrent devices shall beselectively coordinated with all supply side overcurrent devices.

In addition, for Healthcare facilities Article 517.26, Application ofOther Articles requires that The essential electrical system shallmeet the requirements of Article 700, except as amended by Article517. Since Article 517 did NOT specifically address any requirement

for selective coordination, the 2005 Article 700.27 requirement isalso applicable to the essential electrical systems consisting ofequipment necessary for patient care and basic hospital operation,life safety and critical systems for Healthcare facilities.

The following discussion will point out ways to obtain a selectivelycoordinated system utilizing low-voltage (600 volts and below) circuitbreakers. However, the design engineer is cautioned, that as timedelay tripping of the upstream breaker is incorporated into the systemto provide for selective coordination, there is a correspondingincrease of arc flash energy available.

Users should also consider installing a label calling attention toThis equipment has been selectively coordinated and cautionshould be exercised before making changes.

II

. PROTECTIVE DEVICE SHORT-TIME & INTERRUPTINGCONSIDERATIONS

An understanding of protective devices, their operation, selectionand settings in relationship to selective coordination is essential fothe design engineer in order to properly design a selectively coordinated system. Each selected low-voltage circuit breaker must havea voltage rating and interrupting capacity equal to or greater than thsystem voltage and available fault current at its point of applicationin the electrical distribution system. UL

listed series ratings must carefully reviewed before being utilized in a selectively coordinatedsystem, this applies for both two circuit breakers in series, or afuse in series with a circuit breaker. Both fuses and low-voltagecircuit breakers, if properly selected, can be utilized to meet NECrequirements for selective coordination.

It is noted that medium voltage circuit breakers typically have veryhigh momentary ratings. This allows their contacts to remain closeunder very high fault conditions, allowing sufficient time for down-stream devices closest to the overload/fault condition to operate.Thus medium-voltage circuit breakers with their associated relayinwhen properly selected can achieve selective coordination. Also,medium-voltage fuses, whether current limiting type or expulsiontype, if properly selected, can also be readily incorporated into aselectively coordinated system.

The remainder of this paper will focus on the selection and application of low-voltage circuit breakers. When considering selectivecoordination in the normal overload range of low-voltage circuitbreakers, it is only necessary to ensure that the minimum timeband of the upstream device A, does not overlap the maximumtime band of the downstream device B. This information canbe determined from published time-current curves of the devices.[See Figures 1A & 1B.]

A. Low-Voltage Circuit Breaker Short-Time Rating

In considering the use of low-voltage circuit breakers to achieveselective coordination, an understanding of how each type of low-voltage circuit breaker operates under overload and short circuitconditions is necessary. The interrupting rating of the breaker referto The highest current at rated voltage that a device is intended tointerrupt under standard test conditions.

2 On the other hand, theshort-time rating of the low-voltage circuit breaker refers to A ratinapplied to a circuit breaker that, for reason of system coordination,causes tripping of the circuit breaker to be delayed beyond thetime when tripping would be caused by an instantaneous element

3

In other words, the devices ability to stay closed and NOT openthe circuit immediately under fault conditions. For the purposes ofthis article, the short-time rating of the breaker will be broken dow

into two facets: 1) Short-time current rating the current carried bthe circuit breaker for a specified interval, or the maximum currentmagnitude under a fault condition for which the circuit breakercan stay closed, and 2) Short-time delay rating an intentional timdelay in the tripping of a circuit breaker between the overload andthe instantaneous pickup setting. The maximum short-time delayis the maximum amount of time the breaker can keep its contactsclosed under the fault condition. If two breakers are in series, toobtain selective coordination, the upstream breaker must have ashort-time current rating above the actual fault current on the loadside of any downstream breaker. In addition, the upstream breakerhas to have short-time delay capability long enough to allow thedownstream breaker to open and clear the fault condition.

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Selective CoordinationEaton Electrical Inc.1000 Cherrington Parkway


United States

tel: 1-800-525-2000

www.EatonElectrical.com

B. Molded Case Circuit Breakers

Molded Case Circuit Breakers (MCCBs) are manufactured and testedto the UL 489 standard. MCCBs have over-center toggle mechanismsand either a thermal-magnetic or electronic trip unit. The thermalmagnetic trip unit is such that the magnetic pick-up maximum settingis approximately 10 times the trip rating. The electronic trip unit is typ-ically furnished with a fixed instantaneous override of approximately10 to 15 times the breaker frame rating, or trip unit rating. Thus forMCCBs with electronic trip units, for any load side fault above theselevels, the breaker will open. The exact magnitude of current whichwill cause the MCCB to open, will vary by 1) circuit breaker manufac-turer, 2) circuit breaker frame rating, 3) type of trip unit, 4) type/vin-tage of MCCB, 5) manufacturers curve tolerances. For purposesof this paper, it will be assumed that the current magnitude neededto open MCCBs with electronic trips instantaneously is 13 times theframe rating its maximum fixed instantaneous override. The manu-facturers actual data should be used to determine this value. Typicallyfor MCCBs, once the magnetic pick-up or fixed instantaneous over-ride is exceeded, the opening time is 1 cycle or less. [See Figure 1A.]

Although short-time ratings for MCCBs are not covered in theMCCB standards

4

, some MCCBs are equipped with electronic tripunits that have adjustable short delay functions. However, they typ-ically also have either an adjustable instantaneous trip (typically witha maximum setting of 10 times trip ampere) or a fixed instantaneousoverride (of 13 times the frame ampere rating). When the electronictrip is in the short-time pick-up range (below 13 times frame size),they can typically be adjusted up to a maximum short-time delaysetting of approximately 18 cycles (300 ms).

Current Limiting

Current limiting circuit breakers have characteristics that, whenoperating within their current-limiting range, limit the let-through I

2

tto a value less than the I

2

t of a 1/2-cycle wave of the symmetricalprospective current. 5

Current Limiting Circuit Breakers achievethis by opening their contacts very rapidly, such that their I peak

let-through current is reduced to a value much lower than the I peakcurrent available from the system at the MCCBs point of application.

C. Insulated Case Circuit Breakers

Insulated Case Circuit Breakers (ICCBs) are also manufacturedand tested to the UL-489 standard, however, they usually have atwo-step stored energy mechanism and increased short-time ratings.These breakers are typically available in 800 A, 1600 A, 2000 A,2500 A, 3000 A, 4000 A and 5000 A frame sizes. Although theymay have high interrupting ratings, the typical instantaneous overridevalues for ICCBs are 25 kA to 35 kA for the smaller frames and up

to 85 kA for the larger frames. Maximum short-time delay capabilityis generally up to 30 cycles (0.5 s). [See Figure 1A.]

D. Low-Voltage Power Circuit Breakers

Low-Voltage Power Circuit Breakers (LVPCBs) are manufacturedand tested to the UL-1066 Standard, ANSI C37 standards and havea two-step stored energy mechanism. LVPCBs are typically availablein 800 A, 1600 A, 2000 A, 2500 A, 3000 A, 4000 A and 5000 A framesizes. However, even the smaller 800 A frame size is available withvery high short-time current ratings of approximately 85 kA to 100 kA.LVPCBs are capable of keeping their contacts closed for up to 30cycles of fault current, at levels up to their maximum short-timecurrent rating. Thus LVPCBs can normally provide selectivecoordination with relative ease when in series with each other,or when supplying downstream MCCBs or ICCBs. [See Figure 1B.]

F. Effect of X/R Ratio

The interrupting rating for low-voltage circuit breakers is based ontest circuits with a Power Factor (PF) resulting in a Reactance toResistance (X/R) ratio as indicated in Appendix Table 1

The test circuits for circuit breakers with PF and X/R ratios indicatein Appendix Table 1

were selected because in many cases they reresent the real world conditions. For example, LVPCBs are typicallyutilized in applications such as service entrance switchgear, or insecondary switchgear connected to unit substations. Thus, becausthe utility transformers or unit substations transformer have a largereactance (X) component, the X/R ratio of 6.6 or below is typical ofmany of these applications. By contrast, smaller MCCBs having lesthan 10 kA interrupting rating, typically are applied in branch circuitpanelboards being supplied by long lengths of conductors having

higher Resistance (R), thus reducing the X/R ratio.As the system available X/R ratio gets higher, the ratio of availablefirst 1/2-cycle peak current, to the system rms available fault currenbecomes higher, reaching a maximum ratio of 2.823 at zero powerfactor. The higher the X/R ratio (lower fault PF), the harder it is fora circuit breaker to interrupt the fault condition. There are circuitbreaker derating tables for interrupting ratings which should beutilized when the actual system X/R exceeds the test circuit X/Ras indicated in Appendix Table 2

.

Since the trip units instantaneous pickup responds to current peakto ensure selective coordination is obtained, a short circuit coordintion study should be performed to determine the available fault current levels, and X/R ratios, at various key points where protectivedevices are located in the electrical distribution system.

III

. TECHNIQUES TO OBTAIN CIRCUIT BREAKER SELECTIVCOORDINATION

Circuit breakers must have an interrupting capacity (includingconsiderations for X/R ratio) greater than the available fault currentat the point where they are being applied in the electrical distributisystem. In addition, their voltage rating should be greater than orequal to the circuit voltage at their point of application.

A. Selection Based on No-Overlap of Time-Current Curve

Select Specific MCCBs

Selective coordination between upstream MCCBs and downstreamMCCBs requires special consideration under fault conditions. Therare various ways to obtain selective coordination, some applicablebasic methods are as follows: [See Figure 2:

Case 1 illustrates aremote main breaker and Case 2 illustrates a main breaker integralto the panelboard].

q

In the normal overload range, the line side MCCB minimumtrip curve must be greater than the load side breaker maximumtrip curve.

q

For MCCBs with thermal-magnetic trip units, select a line sidebreaker A with a magnetic trip (instantaneous element) settinabove the calculated available fault current level at the load sidedownstream breakers B.

q

For MCCBs with electronic trip units, select a line side breakerA which has a fixed instantaneous override greater than thecalculated available fault current level at the load side downstreabreakers B. In addition, the line side breaker A short-timedelay setting must be selected to allow the load side breakeradequate time to open and clear the fault.

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Referring to Figure 2

, where the available fault current on the loadside of the B MCCBs is higher than the magnetic trip or short-delaypickup rating of what would be the normally selected line side AMCCB, the following methods should be considered for achievingselective coordination:

Select Larger Line Side MCCB

Select a line side breaker A with a larger frame size than wouldnormally be required when just considering the load current require-ments. Typically, the larger the MCCB frame size, the higher themagnetic trip adjustment or fixed instantaneous override value.General Rule

: The magnetic trip setting or fixed instantaneous over-ride value must be higher than the calculated available fault current atload side circuit breaker B (If

2

). However, the larger the MCCB framesize, typically the higher the associated cost and arc-flash energy.

Select a Line Side Low-Voltage Power Circuit Breaker

Utilize the combination of upstream Low-Voltage Power CircuitBreakers (LVPCBs) and downstream Molded Case Circuit Breakers(MCCBs). The required combinations will vary depending on theavailable fault current. Most manufacturers have LVPCBs availablein two types:

Type 1:

LVPCBs with short-time current ratings available up to100 kA and with interrupting ratings up to 100 kA.

Type 2:

For fault currents above 100 kA, LVPCBs are available eitheras combination LVPCB with current limiters, or as true current limitingversions without current limiters. Both types have interrupting ratingsup to 200 kA, but typically have reduced short-time current ratings.

Select Both Line and Load Low-Voltage Power Circuit

Breakers

When utilizing Low-Voltage Power Circuit Breakers, because ofthe high short-time current ratings available in all frame sizes, andtheir maximum 30-cycle short-time delay rating, there is generallyno problem obtaining selective coordination between line and loadside LVPCBs.

B. Reduce Available Fault Current

Transformer Method

Utilize step-down or isolation transformers to reduce the availablefault current level, such that under fault conditions at branch breakerB on the secondary of the transformer, the line side secondarymain breaker A magnetic trip or fixed instantaneous overridepick-up is not exceeded. [See Figure 3.]

An associated advantage ofdividing the loads into smaller groupings is that the system reliability

will be improved in addition to providing selective coordination, if thecorrect secondary MCCB A and branch breakers B are utilized.One manufacturer, Eaton Corporation, has a quick selector table foreasily determining whether selective coordination is achieved whenusing common distribution transformers, secondary MCCBs andbranch MCCBs. [See Appendix Table 3.]

This Table is based onactual test data. It can be utilized to provide selective coordinationbetween indicated secondary main MCCB A and the indicatedbranch MCCBs B by utilizing the following Steps:

Step 1:

Determine the load requirements on the secondary sideof the dry-type transformer.

Step 2:

Select the required kVA rating and ensure that the selectedtransformer has impedance greater than or equal to that shown inthe chart.

Step 3:

Select the manufacturer recommended secondary main

circuit breaker. Frame rating, trip unit, and recommended settingsare shown based on 125% of full load current (FLA) per NECrequirements.

Step 4:

Select the branch circuit breaker, based on requiredamperage. Those branch

circuit breakers listed in the rows corre-sponding to the main breaker will provide selective coordination wthe chosen secondary main circuit breaker. Selective coordinationis based on utilizing selected breakers with appropriate adjustabletrip settings.

Note:

For some transformer kVA ratings, different types of secondary Main Breakers are shown. The most cost-effective secondarymain breaker is shown first. Some larger secondary main breakerframe sizes are also shown for the same kVA rating for thoseapplications requiring a wider range of branch breakers. In additionthe existing Eaton Cutler-Hammer

Series C frame, and the newphysically smaller Series G frame breakers are shown whereapplicable. Example:

Required kVA to serve the 208Y/120 volt loadis 112.5 kVA and the largest required branch circuit breaker is 250amperes. The least expensive recommended secondary main circubreaker is the 400 ampere KD frame with a 400 A/Trip setting. If a100% rated secondary main breaker was required, then a CKD woube selected. In addition, either the Series C type LD or the Series Gtype LG breaker could also be selected with a 600 ampere trip unitand set at 400 amperes.

Consideration of Cable Impedance

As shown in Figure 2

Case 1, the available fault current at branchbreaker B (If

2

) is lower than the fault current at main breakerA (If

1

) because of the cable impedance between A and B.

With the known starting available fault current If

1

(either fromshort circuit study, the utility company information, unit substationtransformer secondary available fault tables

6

, or distributionstep-down or isolation transformers) an estimate of available faultcurrent If

2

can be easily found from simple calculations, or by utiliziTables similar to Appendix Table 4

. [Additional charts for aluminumconductors are available on the Eaton Web site along with a SelectiCoordination Calculator which can be utilized for multiple conductoand/or non-metallic raceways and/or 208Y/120 volts.] Begin byselecting the appropriate starting fault current chart. Then selectthe conductor size and length of conductors from If

1

location to If

2

location. Example

: Assume the fault current given by the utility atmain breaker location is If

1

= 100,000 amperes at 480Y/277 volts.This feeds the 60 ampere remote emergency lighting panelboardwith 1-#6 copper conductor per phase and neutral. The emergencypanelboard will typically have 15 A or 20 A, 1-pole lighting breakers

From the chart, if the emergency panelboard is located 75 feet awfrom the main, then the available fault current at If

2

would be only6700 amperes. A general guideline would be to consider that themain breaker with either a magnetic pick-up setting or fixed instanneous override value of greater than 6700 amperes (including fixedinstantaneous override minimum tolerance) will provide selectivecoordination with the branch breakers. Based on previous discus-sions, as a general rule, typically the minimum frame main electrontrip MCCB that could be utilized would be 600 A frame (availablefault current at If

2

divided by 13 rounded to next larger standardframe size). Based on manufacturers specific data, a smaller framemay be able to be applied. It should be noted that at a lower voltagsay 208Y/120 volt versus 480Y/277 volts there is a greater faultcurrent reduction for the same length conductor.

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Note:

Whenever sizing conductors, besides selective coordinationconsiderations, voltage drop and NEC or local code de-rating factorshave to be considered.

C. Utilize Manufacturers Test Information

Manufacturers, such as Eaton Corporation, provide selective coordi-nation tables between specific line side circuit breakers and loadside circuit breakers, for various maximum values of fault current.[See Appendix Tables 5 & 6.]

These tables are based on circuitbreaker test data. It should be noted that in many cases the allowablefault current levels to achieve selective coordination is significantlyhigher when using the manufacturers specific test information. Thisis attributed to the high speed performance of modern molded casecircuit breakers which in some cases are marked as being currentlimiting: A circuit breaker that does not employ a fusible element

and that when operating within its current limiting range, limitsthe let-through I

2

t to a value less than the I

2

t of a 1/2-cycle wave ofthe symmetrical prospective current.

7

In addition, although somemolded case circuit breakers may not be formally marked as currentlimiting, they still begin to open before the first 1/2-cycle peak, insert-ing arc impedance into the circuit, and thus still reduce the peak let-through current (I

PL

) with resulting lower I

2

t. This current reductionby the downstream breaker reduces the current to a level belowthe instantaneous override of the upstream breaker, thus providingselective coordination.

[See Figure 4.]

It should be noted, that the test circuit utilized by manufacturersto confirm selective coordination must be known and reasonable.Eatons test circuit is similar to the test circuit utilized by UL 489.This test circuit allows for 4 feet of wire on the line side of the lineside breaker and 4 feet of wire for the combination of wire from theload side of the upstream breaker through the downstream breakerto the point of the fault. See Figure 5

for the examples of thetest circuit. For each listed combination, the selective coordinationtest would utilize wire sized based on the trip unit rating for the lineand load breakers.

IV

. EXAMPLES

The following two examples demonstrate application of the abovemethods in the design of selectively coordinated systems, and are forillustrative purposes only. They are not meant to represent an actualfacility. The discussions refer to breaker settings, all of which haveboth current and time tolerances which have to be considered, andshould be determined from actual circuit breaker time-current curves.

Example 1:

Refer to Figure 6:

This single line is to illustrate the useof a combination of the above methods to achieve selective coordina-tion. The incoming service is 480Y/277 volts with 100,000 amperes

rms symmetrical available fault current from the Utility or local gener-ation. The main breaker M1 is a Low-Voltage Power Circuit breaker,which has both 100 kA interrupting, and short-time current rating. Thefeeder breakers F1-F6 are also Low-Voltage Power Circuit Breakers,having 85 kA short-time ratings and 100 kA interrupting ratings.The short-time delay for the main breaker M1 is set at 18 cycles.The short-time delay of the feeder breakers F1 through F3 is set at 6cycles, and at 12 cycles for feeder breaker F4. The feeder breakers F5and F6 in the elevator switchgear are set for 6 cycles. With properoverload settings (long delay pick-up and long delay time), selectivecoordination is achieved between main breaker M1 and feeders F1through F4. It is additionally achieved between feeder F4 and elevatorswitchgear feeder breakers F5 and F6. Thus, should a fault greaterthan the short-time pick-up setting of F3 occur on its load side, F3would open in 6 cycles while the Main circuit breaker M1 would only

open if the fault persisted for 18 cycles. Thus selective coordinationachieved. Similarly, should a fault greater than the short-time currepick-up setting of F4 occur on its load side, then F4 would open in cycles, while the Main circuit breaker M1 would only open if the fapersisted for 18 cycles. Again, selective coordination is achieved.

Additionally, should a fault greater than the short-time pick-up settinof F5 occur on its load side, then F5 would open in 6 cycles, whileupstream breaker F4 would only open if the fault persisted for 12cycles. Again, selective coordination is achieved. [See Figure 7

for time-current curves.]

It should be noted that should a fault occur in the main switchgearmain bus, the main breaker M1 would short-time delay for 18 cyclebefore opening and clearing the fault condition. However, many ofthe microprocessor trip units include a feature called Zone Selectiv

Interlocking (ZSI), which is an option requiring communicationwiring between breakers. With ZSI wired and active, and with afault condition on the main bus, the main breaker would open withoany intentional delay (approximately 3 cycles instead of 18 cycles),minimizing the arc flash energy and equipment damage. However,with ZSI, should the fault occur on the load side of any of the feedebreakers as previously discussed, the main breaker would continueto remain closed for its 18-cycle short-time delay setting, allowingthe downstream breakers closest to the fault to open. Similarly, wZSI between feeder breaker F4 and elevator breakers F5 and F6, iffault occurred in the conductors between the main switchgear andthe elevator switchgear, then F4 would open without any intentiondelay (approximately 3 cycles instead of 12 cycles), minimizingdamage to the cables. Thus, with the proper pick-up and delaysettings, ZSI allows for maintaining selective coordination whilealso minimizing damage from faults which occur on the line side

of downstream breakers.Consider now the circuit supplied by feeder F1. Should a fault occuon the load side of one of the 70 A feeder MCCBs in the emergencdistribution panelboard, this 70 A MCCB will open in less than a cycfor currents above approximately 600 1200 amperes per manufaturers time-current curves. Feeder F1 is set to short-time delay forcycles up to 85 kA, thus providing selective coordination. The 30 kVtransformers which feeds the branch emergency lighting panelboarand the associated Emergency Panelboards have their secondarymain MCCB and branch MCCB selected based on the informationfrom Appendix Table 3

, thus also providing selective coordination

Consider now the circuit supplied by feeder F2. In this case, theavailable fault currents If

3

and if

4

were determined from a coordination study (or can be estimated by use of Tables similar to those ofAppendix Table 4

). Feeder F2 LVPCB will selectively coordinate w

the MCCBs in the Critical Distribution Panelboard (CDP). Here thetype HLD MCCB will open in one cycle or less for faults above itsinstantaneous override setting, while feeder F2 remains closed forits short delay of 6 cycles. The HLD type and frame of 600 amperefeeder breakers in CDP, and the EG type of branch breakers in CriticPanel CP, were both chosen to provide selective coordination baseon manufacturer data from Appendix

Table 5

for the 14,580 Aavailable fault current at the branch critical panel.

Consider now the circuit supplied by feeder F3. The downstreamATS would be required to have a 6-cycle short circuit withstand ratibecause that is the short-time delay setting on the upstream feedeF3. If a fault should occur between the load side of the ATS and thline side of the branch devices within the MCC, it would continue f6 cycles until upstream feeder F3 opens. For the load side devices critical motor control center with combination HMCP and starters,

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well as the branch MCCBs, they will have 1 cycle or less tripping onfault current while feeder F3 has a 6-cycle short-time delay, againproviding selective coordination.

Consider now the circuit supplied by feeder F5. The Elevator Distribu-tion Panelboard EDP has 600 ampere LD breakers with 200 amperetrips feeding the Elevator Panelboard EP-1 which in turn feeds thefused elevator disconnects having J fuses. In this example, selectivecoordination is not required between the circuit breaker in EP-1 andthe associated fused elevator disconnect which it supplies, since theopening of either or both of these devices will result in the opening ofonly its one associated elevator motor circuit. In fact, it is desirable forthe circuit breaker in Elevator Panelboard EP-1 to open (in addition tothe fuse opening), in order to prevent single phasing of the elevatormotor on overloads and/or fault conditions. Based on the availablefault current at EP-1, the type and frame ampere rating of the MCCBsutilized in EDP and EP-1 where selected utilizing a manufacturers(Eaton Corporation) elevator selective coordination table.

[See Appendix Table 7.]

Example 2:

Refer to Figure 8

This single line illustrates a projecthaving 200,000 amperes rms symmetrical available fault currentfrom the utility or local generation. Because of this very high levelof available fault current, special care and consideration is requiredto analyze whether a selectively coordinated system is achieved.The LVPCBs in Figure 8

are either of the current-limiting type withoutLimiters, or the type utilizing a combination of a LVPCB with integralor separately mounted Current Limiters (CL). A variety of CLs areavailable for a given sensor (CT) ampere rating and breaker type.See Appendix Tables 8

10

for a typical chart of breaker/sensor/limiter selection guidelines. These current limiting devices are veryfast acting and consideration has to be given to the downstream

devices they are supplying. The peak let-through (I

PL

) and let-throughenergy (I

2

t) in relationship to the available fault current at the down-stream device must be considered for all current limiting devices inorder to achieve a selectively coordinated system. In addition, forbreakers having current limiters the minimum melt time and totalclearing time must be considered. With reference to Figure 8

,when utilizing devices that are current limiting, either:

1. If the available fault current at the load side device is lessthan that required to melt the line side feeder breakers currentlimiter and not exceeding main breaker M1s short-time rating,then standard MCCBs (not marked current limiting) can beutilized. Consider Feeder F2, where the available fault currentIf

3

at Branch Panelboard BP-2 is limited to a value of 12,805 Adue to cable impedance [note 4/0 cable was selected in lieu of3/0 cable because of voltage drop considerations]. The 1200 AF2 current limiters melt time curve shows that 13,502 A would

have to be available for approximately 0.02 seconds for it to melt.At this current level, the magnetic pick-up or fixed instantaneousoverride of the 150 A breakers in BP-2 is exceeded (13 x 150 =1950) causing them to operate in less than one cycle (0.016seconds). Therefore a standard downstream branch circuitbreaker (not marked current limiting) would open before theupstream current limiter would melt, thus providing selectivecoordination.

or

2. If the available fault current at the load side device is more thathat required to melt the line side feeder breakers current limior exceeds main breaker M1s short-time rating, then currentlimiting MCCBs must be utilized. The load side device mustadditionally be evaluated because the I

peak

and I

2

t let-throughenergy must be low enough to prevent the line side currentlimiting devices from opening. Now consider Feeder F3,where the available fault current at BP-3 is 100,297 amperes.In this case, type FCL current limiting MCCBs were selectedbecause of their low I

peak

and I

2

t let-through energy. This willprovide selective coordination with the 1200 ampere currentlimiter in Feeder F3.

Consider feeder F1: Combination circuit breakers with currentlimiters, or current-limiting (marked) circuit breakers, would berequired in DP-1 such that the let-through currents and energywould not open feeder F1 breaker or its associated current limitersStandard breakers (not specifically marked current limiting) havingadequate interrupting capacity might have been utilized as FeedersF5 if selective coordination were not considered. However, shouldfault occur directly on the load side of a standard (non-marked currelimiting) F5 feeder breaker, the F5 breaker would open, but the1200 ampere Current Limiter in feeder F1might also open, therebylosing selective coordination. In addition, depending on the conductimpedance of feeder conductor FC5 in turn reducing the fault curreat BP-1, either standard breakers or current-limiting breakers wouldbe required for the F6 circuit breakers in BP-1 to ensure the currenlimiter in the line side F5 breaker did not open should a fault occuron the load side of branch breakers F6.

V

. CONCLUSION

The 2005 NEC requirements mandate selective coordination forElevator feeders, Emergency Systems, Legally Required StandbySystems and the essential portion of Healthcare electrical systemsThis paper has presented various methods for obtaining selectivecoordination including: Review of time-current curve information,Proper selection of breaker size and type, Reducing the availablefault current, and Utilization of manufacturers specific test information. Selective coordination utilizing circuit breakers requires moredetailed analysis and design techniques, including specific manufaturers data regarding circuit breaker performance. This puts a largeengineering burden on the design professional. As can be seen frothis discussion, circuit breakers can be utilized to provide a selectivecoordinated system.

FOOTNOTES

1. NEC 2005 NFPA 70: National Electrical Code International

Electrical Code Series. The National Electrical Code and NECare registered trademarks of the National Fire ProtectionAssociation, Quincy, MA.

2. IEEE Std 1015-1997 Page 11 Paragraph 2.1.25. UL is a registertrademark of Underwriters Laboratories, Northbrook, IL.

3. Ibid Page 14 Paragraph 2.1.54.

4. Ibid Page 63 Paragraph 3.40.

5. UL 489-1991.

6. Eaton Corp Cutler-Hammer Consulting Application Guide

13th edition, Page 1.4-7 Table 1.4-3.

7. IEEE Std 1015-1997 Page 146 Paragraph 6.4.

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FIGURE 1A.LOSS OF ENSURED SELECTIVE COORDINATION

FIGURE 1B.FULL SELECTIVE COORDINATION

TimeScale

Minutes

Seconds

Cycles

Hours

Magnetic Pick-up

1

Minim

um

Minim

um

Maxim

um

Maxim

um

"B"

Trip

"A"

TripNotes:

1.MCCB=MoldedCase

CircuitBreaker

2.ICCB=InsulatedCase

CircuitBreaker

Typical Short-Time

Current Setting

Typical Short-Time Delay Setting

MCCBMaximum 18Cycles(300 ms)

ICCBMaximum 30Cycles(0/5s)

MCCBorICCBMaximum Short-Time

CurrentRatingorFixedInstantaneous

Override Value (Typical MCCB1015 TimesFrame Size.

Typical ICCB800A/F=25kA,

1600A/F=35kA,LargerFrames=85kA)

Current Scale LossofEnsured Selective Coordination

MCCBsorICCBs

BLargestDownstream

Feeder/BranchBreaker

B

B

B

Downstream

Upstream

A

Single Line

Upstream

A

TimeScale

Minutes

Seconds

Cycles

Hours

1

Minim

um

Maxim

um

Typical Short-Time

Current Setting

Current Scale

BLargestDownstream

Feeder/BranchBreaker

BB

Downstream

Upstream

A

Single Line

Upstream

A

Notes:

1.LVPCB=LowVoltage

PowerCircuitBreaker

Typical Short-Time Delay Setting

LVPCBMaximum 30Cycles(0.5 Seconds)

LVPCBMaximum Short-Time CurrentRatingorFixed

InstantaneousOverride Value (Typical SmallerFrames

=85kAto100kA, Typical LargerFrames=100kA

Full Selective

CoordinationUpto

Interrupting

Rating

SmallerFrame Fixed

InstantaneousOverride

100kA85kA

LVPCBs

"B"

Trip

"A"

Trip

Minim

um

Maxim

um

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FIGURE 2.SELECTIVE COORDINATION BETWEEN LINE SIDE MCCB

A AND LOAD SIDE MCCB B

FIGURE 3.UTILIZATION OF TRANSFORMERS TO REDUCE

FAULT CURRENT LEVELS

FIGURE 4.CURRENT LIMITING EFFECTS OF MODERN MCCBs

Case 1 Remote Main Breaker

IF1Available Fault Current

at Breaker "A"

Line Side MCCB ""A"

Cable

{IF2 Available Fault Currentat Breaker "B"

LoadSide MCCBs "B"

Panel 1

Line Side MCCB "A"

IF1 IF2

LoadSide MCCBs "B"

Panel 2

Case 2 Main Breaker Integral to Panelboard

Case 1

Step Down

Transformer

IF1

PrimaryBreaker "P"

kVA,Z

SecondaryMain

Breaker"A"

Load(Branch)

Breakers "B"

IF2

480V

208Y/120V

Case 2

Isolation

Transformer

IF1

480V

480Y/277V

IF2

Case 1 Current Limiting Marked MCCB

System Wave on Fault Without MCCB

I t Let-ThroughEnergy2

ActualWave on Fault with MCCB Opening

Time

PS= peak Available From SystemI I

PL = peak Let-Throughwith MCCBI I

1/4t 1/2

Case 2 Modern MCCB Not Marked

Current Limiting

System Wave on Fault Without MCCB

ActualWave on Fault

With MCCB Opening

Timet

PSI

PLI

I t Let-Through

EnergyGreater

Than 1/2 Cycle

2

PSI

PLI

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FIGURE 5.TEST CIRCUIT FOR SELECTIVE COORDINATION

FIGURE 6.EMERGENCY/CRITICAL/ELEVATOR PARTIAL SINGLE-LINE

Example 1

MCCB-A

Trip AUpstreamCircuitBreaker

(Line Side)

4ft.Wire SizedforTrip A

MCCB-B

Trip B

Available FaultCurrentI

f

Total 4ft.(Line &Load)Wire SizedforTrip B

Available FaultCurrentIf

Given asrmsSymmetrical withATestX/RRatio asGiven

inAppendix Table 1

Example 2

MCCB-A

Trip A

MCCB-B

TripB

PanelboardorAssembly

I f1 = 100 kA

I f5 = 51,141

I f3 = 40,143

I f4 = 14,580

I f6 = 27,063

I f7 = 11,262

I f8 = 4,878

I f2 = 62,639

Main"M1"

3200 AF

3000 ATPowerCircuit

Breaker(Typical)

800 AF

800 AT

F1

HFD

70 A

TypicalHLD

600 AF

100 AT

1600 AF

1600 AT

F4

800 AF

400 ATF2

800 AF

600 AT

F3

800 AF

800 AT

F6

800 AF

800 AT

F5

Notes:1. MLO = MainLugsOnly2. Cutler-HammerFramesSelected for

IllustrativePurposes3. A/F F = FrameSize4. ___ A/T T = TripSize

ISC = 100 kA

480 Y/277V,3 ,4-Wire

4600 kcmil/200 ft.

1 500 kcmil/75 ft.

1 #3/ &NTotal50 ft.

600 A ATS

HMCP

LD

600 AF

200 AT

200 AATS

FD

60 A

FD

30 A

J

60 A

J

30 A

VFD

1600 A

ElevatorSwitchgear

Normal

2500 kcmil/175 ft.

1 #1015 ft.

1 3/0/Total 150 ft.

2500 kcmil/60 ft.

Normal

800 A

EmergencyDistributionPanelJD

225 AF100 AT

Normal

Normal

Normal

E E

400 A CriticalDistributionPanelCDP

100 A ATS

100 A CriticalPanelCPwithEGBranchBreakers

800 A ElevatorDistributionPanelEDP

200 A ElevatorPanelboard

EP 1

200 A ATS

CriticalMotorControlCenter

HFD70 AJD250 A/F

125 A/T

JD250 A/F125 A/T

100 A BranchEmergencyLightingPanel1BABBreakers

BranchEmergency150 A LightingPanel

w/BABBreakers

100 A ATS

30 kVA

480 208Y/120 VZ>7.5%

30 kVA

480 208Y/120 VZ>7.5%

30 kVA

480 208Y/120 VZ>7.5%

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FIGURE 7.LVPCB TIME/CURRENT CURVES FOR FIGURE 6, EXAMPLE 1

FIGURE 8.SELECTIVE COORDINATION WITH CURRENT LIMITING DEVICES, EXAMPLE 2

800 AF

800 ATF5

1600 AF

1600 ATF4

51.1kA

3200 AF

3000 ATMain

100 kA

PartialSingleLine

FullySelectiveforAvailable FaultCurrent

3200A

1600A

800A

Time

Scale

18 Cycle

12Cycle

6Cycle

800 A 2400 A

4800 A

6000 ACurrentScale

51.1kA 85kA 100 kA

Max. FaultCurrentat F5

I f1 = 200,000

I f3 = 12,805A

I f4 = 100,297A

I f2 = 61,807A

Notes:

1. CL = CurrentLimiters2. BP = BranchPanelboard3. DP = DistributionPanelboard4. ISC = ShortCircuitCurrent

ISC = 200 kA480 Y/277V, 3 , 4Wire

AlternateMainLVPCBwithCLTruck

200 ABranchPanelBP2with 150 A/F

StandardBreakers

400 ABranchPanelBP3with 150 A/FFCLCurrentLimitingCircuitBreakers

BranchPanelBP1

FC5

F6

F5

F7

4000 ACL

F4CL

2000 A

1600 AF1200 AT

F3CL

1200 A

800 AF400 AT

F2CL

1200 A

800 AF200 AT

F1CL

1200 A

800 AF600 AT

Main"M1"TypeMDSXCurrentLimitingBreaker4000 AF3000 AT

Main"M1"DSII 632 LVPCB3200 AF3000 AT

FeedersTypicalMDSL

600 ADistributionPanelDP1

2 350 kcmil/&N

1 500 kcmil/&N25 ft.

1 4/0/ &N250 ft.

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VI. APPENDIX TABLES

TABLE 1.TEST CIRCUIT POWER FACTORS

TABLE 2.CIRCUIT BREAKER INTERRUPTING RATING

DE-RATING FACTORS

Note:The values in this table are based upon information extractefrom IEEE 1015 (Blue Book). Applying Low-Voltage Circuit BreakerUsed in Industrial and Commercial Power Systems, Tables 3-24 &

INTERRUPTINGRATING KA

PF TESTRANGE

TEST X/RRANGE

MCCBs and ICCBs

10 or lessOver 10 to 20Over 20

0.45 0.500.25 0.300.15 0.20

1.98 1.733.87 3.186.6 4.9 (MCCB Typical 4.899)

LVPCBs

ALL 0.15 6.6

SYSTEM

%PF

SYSTEM

X/R

INTERRUPTING RATING MCCB LVPCB

I 10 KA 10 KA < I 20 KA I > 20 KA UNFUSED FUS

503025

1.733.183.87

1.0000.8470.806

1.0001.0000.952

1.0001.0001.000

1.0001.0001.000

1.0001.0001.000

201512

4.96.598.27

0.7630.7190.690

0.9000.8470.813

1.0000.9430.909

1.0001.0000.962

1.0000.9350.893

107.0

5.0

9.9514.25

19.97

0.6710.645

0.629

0.7940.763

0.740

0.8850.847

0.820

0.9350.900

0.877

0.8700.826

0.793

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TABLE 3.DETERMINING COORDINATION OF MCCBS UTILIZING COMMON DISTRIBUTION STEPDOWN /

ISOLATION TRANSFORMERS

See Eatons Consulting Application Guidefor Typical Impedances, Page 19.1 for General Purpose Transformers, 19.2 for TP-1 & K-Factor Transformers,and refer to Eaton for Harmonic Mitigating and specialty transformers.

IT-Interchangeable Trip, NIT-Non Interchangeable Trip. Magnetic trip set to 10x. Digitrip OPTIM 550 electronic trip unit available.

TRANSFORMER SECONDARY MAIN MCCB BRANCH BREAKER

KVASECONDARYVOLTAGE

SECONDARYFULL LOADCURRENT (FLA)

TRANS-FORMER %Z (MIN.)

LET-THROUGHAIC (RMS)

MCCBTYPE /FRAME

TRIPUNIT

125%FLA

MCCBTRIP RATING(NEC 450.3(B))

BRANCHTYPE FORSELECTIVITY

MAX.FRAMERATING

MAX.TRIPRATIN

15 208Y/120 42 3.8 1096 Series C[FDB or FD](225 A Frame)

Thermal /Magnetic

52 60 A BAB 100 A 60 A

30 208Y/120 83 7.5 1110 Series CJD(250 A Frame)

Thermal /Magnetic

104 125 A BAB 100 A


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TABLE 3. DETERMINING COORDINATION OF MCCBS UTILIZING COMMON DISTRIBUTION STEPDOWN /

ISOLATION TRANSFORMERS (CONTINUED)

See Eatons Consulting Application Guidefor Typical Impedances, Page 19.1 for General Purpose Transformers, 19.2 for TP-1 & K-Factor Transformers,and refer to Eaton for Harmonic Mitigating and specialty transformers.

IT-Interchangeable Trip, NIT-Non Interchangeable Trip. Magnetic trip set to 10x. Digitrip OPTIM 550 electronic trip unit available.

TRANSFORMER SECONDARY MAIN MCCB BRANCH BREAKER

KVASECONDARYVOLTAGE

SECONDARYFULL LOADCURRENT (FLA)

TRANS-FORMER %Z (MIN.)

LET-THROUGHAIC (RMS)

MCCBTYPE /FRAME

TRIPUNIT

125%FLA

MCCBTRIP RATING(NEC 450.3(B))

BRANCHTYPE FORSELECTIVITY

MAX.FRAMERATING

MAX.TRIPRATIN

150 208Y/120 416 2.4 17348 Series CND-80%CND-100%Series GNGS-80%(1200 A Frame)

Electronic(Digitrip RMS310)

520 1200 A T.U. Set@ 600 A

ED, [FDB (NIT)& FD (IT)]

225 A 225 A

Series C JD 250 A 250 A

Series CDK, KD-80%,CKD-100%

400 A 400 A

Series CLD-80%CLD-100%

600 A 600 A

Series GL630E-80%

600 A 600 A

225 208Y/120 625 3.5 17844 Series CND-80%CND-100%Series GNGS-80%(1200 A Frame)


781 1200 A T.U. Set@ 800 A


225 A 225 A



400 A 400 A


600 A 600 A

Series G

L630E-80%

600 A 600 A

300 208Y/120 833 >4.7 17717 Series CND-80%CND-100%Series GNGS-80%(1200 A Frame)


1041 1200 A T.U. Set@ 1200 A


225 A 225 A



400 A 400 A


600 A 600 A

Series GL630E-80%

600 A 600 A

500 208Y/120 1388 6.3 22030 Series CRD-80%CRD-100%

Series GRGU-80%


1735 2000 A T.U. Set@ 2000 A

QPHW, QBHW 100 A 100 A

1.3 106759 EDC, FDC(2- & 3-Pole Only)

225 A 225 A

2.4 57828 JD 250 A 250 A

DK, KD-80%, 400 A 250 A


600 A 600 A

Series GL630E-80%

600 A 600 A

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TABLE 4.REDUCTION IN FAULT CURRENT DUE TO CABLE IMPEDANCE 480Y / 277 VAC, 3-PHASE

The values in tables are fault amperes available at end of cables. Copper, 3 - Single Conductor Cables - Temperature 75C, in Magnetic Duct & Steel Interlocked Armour.

CONDUCTORSIZE

CABLE LENGTH (FEET)

10 25 50 75 100 150 200 250

Starting Available Fault Current Equals 25,000 Amperes

#14#12#10

6,7709,267

12,094

3,2334,7676,816

1,7282,6353,946

1,1791,8202,777

8951,3912,142

604945

1,470

456715

1,119

366575903

#8#6#4

14,41117,07419,303

8,81311,57114,386

5,3497,528

10,098

3,8405,5797,780

2,9954,4316,327

2,0803,1404,607

1,5932,4313,622

1,2911,9832,984

#3#2#1

20,51921,01421,678

16,17116,95818,076

11,95112,83014,156

9,47710,31911,633

7,8528,6299,873

5,8476,5017,580

4,6575,2156,151

3,8704,3535,175

1/02/03/0

22,21622,64923,012

19,03619,84820,559

15,36916,45717,458

12,88714,05615,170

11,09512,26613,412

8,6819,776

10,888

7,1308,1279,164

6,0496,9537,911

4/0250 kcmil300 kcmil

23,29723,43323,561

21,13721,41921,689

18,30918,73519,152

16,14716,64917,146

14,44314,98015,521

11,92512,48013,047

10,15510,69411,254

8,8429,3569,894

350 kcmil500 kcmil600 kcmil

23,67723,81623,860

21,93522,23722,333

19,53920,02420,180

17,61518,21118,406

16,03616,70016,918

13,59814,32214,564

11,80412,53712,785

10,42811,14811,393


#14#12#10

7,83011,37515,952

3,4575,2697,892

1,7902,7814,284

1,2081,8892,940

9111,4302,238

611963

1,514

460726

1,145

369582920

#8#6#4

20,24725,92831,441

10,69815,05620,197

5,9908,862

12,654

4,1596,2799,213

3,1864,8627,244

2,1703,3505,074

1,6452,5553,905

1,3252,0653,173

#3#2#1

34,80036,24738,272

23,90125,66028,311

15,70417,25919,746

11,69413,00215,159

9,31510,42912,302

6,6217,4728,934

5,1365,8227,014

4,1954,7695,773

1/02/03/0

39,97941,40342,633

30,73932,91434,916

22,19124,53226,824

17,36219,55221,777

14,26016,25318,328

10,50512,15213,920

8,3169,704

11,221

6,8818,0769,398


43,62344,10144,558

36,61737,46938,304

28,88629,96131,042

23,85024,95926,095

20,30921,38922,508

15,66016,63117,654

12,74213,60414,523

10,74111,51012,335


44,97245,47945,640

39,07840,04740,360

32,07233,39933,837

27,19728,64429,128

23,60825,07425,570

18,67820,07120,550

15,45216,73317,178

13,17614,34614,756


#14#12#10

8,26112,30917,851

3,5385,4618,330

1,8122,8344,410

1,2181,9132,999

9171,4442,272

614969

1,530

461729

1,153

370584926

#8

#6#4

23,407

31,34739,780

11,520

16,73623,339

6,239

9,41913,820

4,278

6,5539,816

3,255

5,0257,611

2,202

3,4265,252

1,664

2,6004,009

1,337

2,0943,242

#3#2#1

45,31247,79751,382

28,43130,95634,898

17,54019,50322,739

12,68214,23616,864

9,93111,20913,401

6,9277,8649,500

5,3186,0577,358

4,3154,9256,004

1/02/03/0

54,50757,18859,561

38,66242,16745,509

26,04329,32832,665

19,63522,48325,475

15,75718,22820,879

11,29613,22315,343

8,80410,37512,128

7,2128,536

10,027


61,51162,46663,387

48,44249,94651,439

35,77537,43939,142

28,35929,94131,591

23,49024,94626,482

17,48518,70420,009

13,92514,96116,079

11,57012,46613,440


64,22965,26865,599

52,84654,63455,217

40,79542,96643,693

33,22035,40536,148

28,01730,10730,825

21,33523,17223,812

17,22618,83419,399

14,44415,86416,366

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TABLE 4. REDUCTION IN FAULT CURRENT DUE TO CABLE IMPEDANCE 480Y / 277 VAC, 3-PHASE (CONTINUED)

The values in tables are fault amperes available at end of cables. Copper, 3 - Single Conductor Cables - Temperature 75C, in Magnetic Duct & Steel Interlocked Armour.

CONDUCTORSIZE

CABLE LENGTH (FEET)

10 25 50 75 100 150 200 250


#14#12#10

8,49512,83618,980

3,5805,5638,568

1,8232,8614,476

1,2231,9263,029

9201,4512,289

615972

1,538

462731

1,158

370586928

#8#6#4

25,38735,00545,861

11,98017,72425,308

6,3719,724

14,487

4,3406,700

10,148

3,2915,1107,809

2,2183,4665,345

1,6732,6224,063

1,3432,1093,277

#3#2#1

53,37456,85662,001

31,40834,51739,492

18,62920,85924,604

13,24214,94517,868

10,27211,64414,028

7,0908,0769,811

5,4146,1827,543

4,3785,0076,127

1/02/03/0

66,61070,65874,316

44,38149,06353,648

28,51932,50636,656

21,01024,30427,839

16,63119,40722,441

11,73813,83316,170

9,07010,74612,639

7,3908,786

10,373


77,37678,89380,367

57,77159,92262,084

40,61842,77845,016

31,31933,26135,309

25,48527,20829,045

18,56719,94821,439

14,60315,74616,990

12,03413,00714,070


81,72783,41683,958

64,14566,79867,673

47,21550,14851,141

37,35640,14341,100

30,90333,46534,355

22,96825,11125,865

18,27620,09520,740

15,17516,74917,310


#14#12#10

8,74213,40920,262

3,6245,6688,820

1,8342,8884,543

1,2281,9383,060

9231,4582,307

616975

1,546

463733

1,162

370587931

#8#6#4

27,73439,62854,137

12,47818,83727,640

6,51010,05015,223

4,4046,853

10,504

3,3275,1998,018

2,2353,5075,442

1,6822,6454,119

1,3492,1243,314

#3#2#1

64,92570,15178,153

35,08139,00545,478

19,86322,41726,802

13,85315,72819,000

10,63612,11414,716

7,2628,299

10,142

5,5136,3127,737

4,4435,0926,254

1/02/03/0

85,62092,42798,788

52,08758,65665,330

31,51536,45641,759

22,59226,44730,687

17,60720,75024,256

12,21614,50217,092

9,35211,14613,195

7,5769,051

10,745


104,269107,043109,775

71,54974,87878,285

46,97949,89252,963

34,97037,40940,019

27,85129,92232,159

19,79221,36923,089

15,35116,61918,010

12,53713,59614,763


112,327115,542116,585

81,59085,93267,673

56,03460,21451,141

42,67046,34441,100

34,45237,66734,355

24,87227,40525,865

19,46121,53820,740

15,98417,74017,310


#14#12#10

8,87213,71620,970

3,6465,7228,951

1,8402,9024,578

1,2301,9443,076

9241,4622,316

617977

1,550

463734

1,165

371587933

#8

#6#4

29,078

42,43159,506

12,743

19,44828,975

6,581

10,22115,619

4,436

6,93210,691

3,346

5,2448,127

2,243

3,5275,492

1,687

2,6574,148

1,352

2,1313,332

#3#2#1

72,80379,43989,857

37,25941,71749,208

20,54323,28728,055

14,18116,15219,621

10,82812,36315,086

7,3518,416

10,317

5,5646,3797,839

4,4765,1366,320

1/02/03/0

99,872109,257118,258

57,03865,01273,313

33,26238,81544,883

23,47627,66632,341

18,13921,49325,278

12,47014,86117,593

9,50111,35713,491

7,6739,190

10,941


126,201130,287134,357

81,23785,55590,032

50,97054,41758,091

37,13539,89642,879

29,20731,49333,980

20,46722,15824,013

15,75417,09218,567

12,80513,91115,135


138,200143,099144,702

94,431100,297102,282

61,80766,93168,710

45,93650,22351,731

36,55140,19041,480

25,94828,71729,707

20,11322,34023,140

16,42118,28018,950

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TABLE 5.BREAKER SELECTION FOR SELECTIVE COORDINATION MCCB-MCCB

Notes:

q The table indicates the maximum fault current value expressed in kA for which coordination is ensured.

q Dashes () indicate Not Applicable.

q The interrupting rating of the downstream (branch) breakers must be adequate for the appropriate fault current at the installation point (fstand-alone or series combination ratings.)

q Electronic trip units are required on L, N and R frames (mains only) for short time delay function.

q Short time delay settings or magnetic trip settings must be set to properly coordinate for low level faults.

DOWNSTREAM (BRANCH) CB UPSTREAM (MAIN) MCCB

RATING EG (125 A) F (225 A) JG (250 A) J (250 A) K (400 A) L (600 A) LG (630A) N (1200 A) R (2500 A

All Values in (kA) rms Current Levels at 240 Vac or Less

BR, BAB, HQP & QC(10 kA)

15 1.2 2.2 4.0 10.0 10 10 10 10 10

20 1.2 2.2 3.4 5.0 8.0 10 10 10 10

30 1.2 2.2 3.4 5.0 8.0 10 10 10 10

40 0.8 2.2 3.4 4.2 6.0 10 10 10 10

50 0.8 2.2 2.5 4.2 6.0 10 10 10 10

60 0.8 2.2 2.5 4.2 6.0 10 10 10 10

70 2.2 2.5 4.2 5.0 10 10 10 10

80 2.2 2.5 4.2 5.0 10 10 10 1090 2.2 2.5 4.2 5.0 10 10 10 10

100 2.2 2.5 4.2 5.0 10 10 10 10

125 4.2 4.2 10 10 10 10

150 4.2 10 10 10 10

BRH, QPHW, QBHW& QCHW (22 kA)

15 1.2 2.2 4.0 10.0 10 22 22 22 22

20 1.2 2.2 3.4 5.0 8.0 22 22 22 22

30 1.2 2.2 3.4 5.0 8.0 22 22 22 22

40 0.8 2.2 3.4 4.2 6.0 22 22 22 22

50 0.8 2.2 2.5 4.2 6.0 22 22 22 22

60 0.8 2.2 2.5 4.2 6.0 22 18 22 22

70 2.2 2.5 4.2 5.0 22 18 22 22

80 2.2 2.5 4.2 5.0 22 18 22 22

90 2.2 2.5 4.2 5.0 22 18 22 22

100 2.2 2.5 4.2 5.0 22 18 22 22

125 4.2 4.2 18 18 22 22

150 4.2 18 18 22 22

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TABLE 5. BREAKER SELECTION FOR SELECTIVE COORDINATION MCCB-MCCB (CONTINUED)

Notes:


q Dashes () indicate Not Applicable.

q The interrupting rating of the downstream (branch) breakers must be adequate for the appropriate fault current at the installation point(for stand-alone or series combination ratings.)

q Electronic trip units are required on L, N and R frames (mains only) for short time delay function.


DOWNSTREAM (BRANCH) CB UPSTREAM (MAIN) MCCB

RATING EG (125 A) F (225 A) JG (250 A) J (250 A) K (400 A) L (600 A) LG (630 A) N (1200 A) R (2500 A

All Values in (kA) rms Current Levels at 480 Vac or Less

EG Family 15 1.3 2.2 2.5 2.5 5.6 35 35 65 65

30 1.3 2.2 2.5 2.5 5.6 35 35 65 65

50 1.3 1.8 2.3 2.3 5.2 18 18 65 65

60 1.3 1.8 2.3 2.3 5.2 18 18 65 65

125 1.8 2.3 2.3 5.2 18 18 35 65

F Family 15 1.8 2.5 2.5 5.0 12 12 65 65

40 1.8 2.5 2.5 5.0 12 12 65 65

100 1.8 2.3 2.3 3.2 12 12 30 65225 3.2 12 12 28 65

JG Family 70 2.3 2.3 3.2 12 12 35 65

160 3.2 12 12 30 35

250 3.2 10 10 25 35

J Family 70 3.2 12 12 35 65

125 3.2 12 12 30 65

250 3.2 10 10 25 35

K Family 100 10 10 22 35

225 10 10 22 35

400 10 10 22 35

L Family 300 6 6 18 35

400 6 6 18 35

500 18 35

600 18 35

LG Family 300 6 6 50 50

400 6 6 50 50

500 18 50

630 18 50

N Family 800 12 15

1200 15

1600 15

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TABLE 6.BREAKER SELECTION FOR SELECTIVE COORDINATION MAGNUM-MCCB

T = Total Coordination up to the interrupting rating of the main breaker at 480 Vac or less.

Values have not yet been tested.Note:Dashes () indicate Not Applicable.

DOWNSTREAM(BRAND) MCCB UPSTREAM (MAIN) LVPCB

MAGNUMNARROW (42 KA) M

AGNUM

STANDARD

(42KA)

MAGNUMNARROW (50 KA)

MAGNUMNARROW (65 KA)

MAGNUMSTANDARD (65 KA)

RATING 800 1200 1600 800 800 1200 1600 800 1200 1600 2000 800 1200 1600 2000 2500 3000 320

EG Family 15 T T T T T T T T T T T T T T T T T T

40 T T T T T T T T T T T T T T T T T T


F Family 15 T T T T T T T T T T T T T T T T T T




JG Family 50 T T T T T T T T T T T T T T T T T T




J Family 70 T T T T T T T T T T T T T T T T T T



K Family 100 T T T T T T T T T T T T T T T T T T



L Family 250 T T T T T T T T T T T T T T T T T T



LG Family 250 T T T T T T T T T T T T T T T T T T



N Family 800 T T T T T T T T T T T T T

1200 T T T T T T T T

1600 T T T T

R Family 1600

2000

2500

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TABLE 6. BREAKER SELECTION FOR SELECTIVE COORDINATION MAGNUM-MCCB (CONTINUED)

T = Total Coordination up to the interrupting rating of the main breaker at 480 Vac or less. Values have not yet been tested.

Note:Dashes () indicate Not Applicable.

DOWNSTREAM(BRAND) MCCB

UPSTREAM(MAIN) LVPCB

MAGNUM STANDARD (85 KA) MAGNUM

NARROW

(100KA)

MAGNUM STANDARD (100 KA)

RATING 800 1200 1600 2000 2500 3000 3200 4000 5000 800 800 1200 1600 2000 2500 3000 3200 4000 5000 600

EGFamily

15

40

125

F

Family

15 T T T T T T T T T T T T T T T T T T T T

40 T T T T T T T T T T T T T T T T T T T T100 T T T T T T T T T T T T T T T T T T T T


JGFamily

50 T

100 T

160 T

250 T

JFamily




KFamily




LFamily 250 T T T T T T T T T T T T T T T T T T T T400 T T T T T T T T T T T T T T T T T T T T


LGFamily

250 T

400 T

630 T

NFamily

800 T T T T T T T T T T T T T T T T T

1200 T T T T T T T T T T T T T T T

1600 T T T T T T T T T T T T T

RFamily

1600

2000

2500

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TABLE 6. BREAKER SELECTION FOR SELECTIVE COORDINATION MAGNUM-MCCB (CONTINUED)

T = Total Coordination up to the interrupting rating of the main breaker at 480 Vac or less. Values have not yet been tested.

Notes:

q The interrupting rating of the downstream (branch) breakers must be adequate for the appropriate fault current at the installation point(for stand-alone or series combination ratings).


DOWNSTREAM (BRAND) MCCB

UPSTREAM (MAIN) LVPCB

MAGNUM STANDARD CURRENTLIMITING (200 KA)

MAGNUM DOUBLE-WIDE CURRENTLIMITING (200 KA)

RATING 800 1200 1600 2000 2000 2500 3000 3200 4000

EGFamily

15 T T T T T T T T T



FFamily





JGFamily

50 T T T T T

100 T T T T T

160 T T T T T

250 T T T T T

JFamily

70 T T T T T

125 T T T T T

250 T T T T T

KFamily

100 T T T T T

225 T T T T T

400 T T T T T

LFamily

250 T T T T T

400 T T T T T

600 T T T T T

LGFamily

250 T T T T T

400 T T T T T

630 T T T T T

NFamily

800

1200

1600

RFamily

1600

2000

2500

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TABLE 7.ELEVATOR CIRCUIT COORDINATION

Thermal magnetic trip. Electronic trip unit.

Notes:


q The interrupting rating of the downstream (branch) breakers must be adequate for the appropriate fault current at the installation point(for stand-alone or series combination ratings).

q Electronic trip units are required on L and N frames (mains only) for short time delay function.


FIGURE 9.ELEVATOR PANELBOARD ELECTRICAL SCHEMATIC

Per the electrical system shown in the one line diagram, any branch Class J fuse can be used downstream from the specified feeder.In this application, selective coordination is NOT required by the NEC between the feeder circuit breaker and the associated downstreambranch fused elevator disconnect because the opening of either or both of these devices will result in the opening of ONLY its oneassociated elevator motor circuit.

MAIN MCCB

FEEDER MCCB

30 A 60 A 100 A 200 A

All Values Shown in rms (kA) Current Levels at 480 Vac or Less

FD / HFD FD/HFD1.8 / 1.8

FD/HFD1.8 / 1.8

FD/HFD1.8 / 1.8

FD/HFDNA

JD / HJD FD/HFD2.5 / 2.5

FD/HFD2.5 / 2.5

FD/HFD2.3 / 2.3

FD/HFD2.3 / 2.3

KD / HKD FD/HFD5 / 5

FD/HFD5 / 5

FD/HFD/JD/HJD3.2 / 3.2 / 3.2 / 3.2

FD/HFD/JD/HJD3.2 / 3.2 / 3.2 / 3.2

(LD / HLD FD/HFD12 / 12

FD/HFD12 / 12

FD/HFD/JD/HJD/KD/HKD12 / 12 / 12 / 12 / 10 / 10


LG FD/HFD12 / 12

FD/HFD12 / 12



HMDL FD/HFD12 / 12

FD/HFD12 / 12



HND FD/HFD35 / 65

FD/HFD35 / 65



Elevator

Main

Distribution

Panel

Main

Feeder Feeder

Elevator Panelboard

BranchFuse

Elevator

Disconnect

Switch

Class

J

EE

Class

J

BranchFuse

Elevator

Disconnect

Switch

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TABLE 8.BREAKER/SENSOR/LIMITER SELECTION GUIDELINES TYPE DSLII POWER CIRCUIT BREAKERS

Notes:

q Based on Eatons Cutler-Hammer equipment.

q Minimum limiter rating is used only when protection of downstream equipment is required. Not completely coordinated with breaker toavoid nuisance blowing.

q Normal rating lowest rating that can typically be coordinated with breaker to avoid nuisance blowing.

q Highest available rating for protection of breaker only.

TABLE 9.BREAKER/SENSOR/LIMITER SELECTION GUIDELINES MAGNUM DSL

Select the Magnum breaker frame, then the current sensor and rating plug, and finally the current limiter. Current limiters are mounted integral to circuit breaRefer non-automatic MDSL breaker application requests to Eaton.

Refer to MDSL current limiter curves for let-through and time characteristics. The minimum selection provides for lowest current let-through, but trip unit settings must be considered to avoid nuisance operation. The recommended selection avoids nuisance limiter operation and allows for system coordination within the trip unit settings while minimizing let-through The maximum selection provides for maximum system coordination with let-through characteristics per the limiter selected. Heat sinks applied in conjunction with current limiters on this breaker rating.

BREAKERTYPE

SENSOR AMPERERATING

LIMITER RATING AMPERES

MINIMUM NORMAL MAXIMUM

DSLII-308DSLII-308DSLII-308

200300400

250400600

120012001200

200020002000


600800600

8001200800

120016002000

200020003000


80012001600

10002000

200025003000

30003000

DSLII-620

DSLII-632DSLII-840

2000

2400 & 32003200 & 4000

3000

2500 40002500 5000

MAGNUM DSL BREAKER

CONTINUOUS CURRENTFRAME RATING

SENSOR

& RATINGPLUG In

MDSL CURRENT LIMITER SELECTION

MINIMUM RECOMMENDED MAXIMUM

800 A 1200 A 1600 A 200 250 A 300 A 400 A 600 A 800 A 1200 A 1600 A 2000 A 2500 A 3000 A

800 A 1200 A 1600 A 250 400 A 600 A 800 A 1200 A 1600 A 2000 A 2500 A 3000 A

800 A 1200 A 1600 A 300 400 A 600 A 800 A 1200 A 1600 A 2000 A 2500 A 3000 A

800 A 1200 A 1600 A 400 600 A 800 A 1200 A 1600 A 2000 A 2500 A 3000 A

800 A 1200 A 1600 A 600 800 A 1200 A 1600 A 2000 A 2500 A 3000 A

800 A 1200 A 1600 A 800 1200 A 1600 A 2000 A 2500 A 3000 A

1200 A 1600 A 1000 1600 A 2000 A 2500 A 3000 A

1200 A 1600 A 1200 2000 A 2500 A 3000 A

1600 A 2000 A 1600 3000 A

2000 A 2000 3000 A

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TABLE 10.MAGNUM TYPE MDSX CURRENT LIMITING

LINE SIDE BREAKERS (WITHOUT CURRENT LIMITERS)

COMBINATIONS PROVIDING SELECTIVE COORDINATION

UP TO 200,000 A

2000 A limiter rating when used with 1600 A or above sensor/rating plugshould be used only when protection of downstream equipment is required.Not completely coordinated with breaker to avoid nuisance blowing.

BIOGRAPHIES

CHARLES J. NOCHUMSON, PE NATIONAL APPLICATION ENGINEER

Charles J. Nochumson is an Application Engineer for Eaton Corportion and was previously an Application Engineer with WestinghousElectric Corporation in their Distribution and Control Business Unit f29 years. Mr. Nochumson is co-author of an IEEE paper on TransfConsiderations in Standby Generator Application, author of a TAPand IEEE paper on Application of New Technologies in Power CircBreakers with Higher Interrupting Capacity and Short Time RatingsChuck has written and presented a paper at the IEEE/IAS Pulp &Paper 2001 Conference on Considerations in Application andSelection of Unit Substation Transformers which was selected fopublication in IEEE Transactions. He has also been a guest speakerfor Plant Services magazine and the International Association ofElectrical Inspectors-Chicago Division. He has written an articleon Basic Electrical Distribution Systems for Electrical Distributormagazine and also authored articles in Plant EngineeringmagazineIn addition, Chuck has been a speaker numerous times at ChicagoIEEE-IAS meetings on a variety of technical topics and has been aninstructor at their yearly February Technical Seminars. In addition hhas been a past speaker at IAEI Chicago Division meetings, latesttopic on Motor Protection. Besides providing technical and applicatiinformation on Cutler-Hammer products for consulting and designengineers, he provides technical direction for the committee thatpublishes Eatons Consulting Application Guideand its ProductSpecification Guide. Mr. Nochumson is a Professional Engineer anSenior Member of IEEE, as well as an Associate Member of IAEI.He was indoctrinated into the Chicago Electric Association Hallof Fame in 2005. He is presently located in Phoenix as EatonsNational Application Engineer.

KEVIN J. LIPPERT MANAGER OF CODES & STANDARDS

Kevin J. Lippert is the Manager, Codes & Standards with Eatonin Pittsburgh, PA. He began his career in 1986 with WestinghouseElectric Corp., which was acquired by Eaton Corp. (1994). He isheavily involved with the National Electrical Manufacturers Assocition and has held Chairmanships of several NEMA Low VoltageDistribution Equipment committees. He is a member of severalUnderwriters Laboratories (UL) Standards Technical Panels (STP)and is a U.S. Representative to several International ElectrotechnicCommission (IEC) Subcommittees. Kevin is an alternate member oNational Electrical Code Making Panel 8. He has published industryarticles, IEEE White Papers, and is a Senior member of IEEE.

Cutler-Hammer is a federally registered trademark of Eaton Corporation.

2006 Eaton CorporationAll Rights ReservedPrinted in USAPublication No. IA01200001E / Z4477May 2006

LINE SIDE MDSXFRAME AMPERE RATING

LOAD SIDE MDSLBREAKER FRAME

MAXIMUM MDSLLOAD LIMITER

3200 A through 5000 A 800 A & 1600 A 2000 A

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Protection Coordination Tabels