Fuse Diagnostic Sizing Charts - Cooper Bussmann

1 202 2005 Cooper BussmannFuse Diagnostic Sizing ChartsBallastsCapacitors (NEC 460) fuse & Holder RecommendationsFuseHolder(s) FuseHolder(s)BAFHEBKTK-RHEYBANHEXFNQ-RKT KHPC-DLP-CCFNMFNQFNWM ercury, Sodium, Other (Mercury,Sodium, etc.)IndoorOutdoorConsult fixture manufacturer for size and fixture manufacturer for size and fixture manufacturer for size and & Holder RecommendationsFuseHolder(s) FuseHolder(s)GLRHLRGLQHLQGMFGMQGRFFuse & Holder RecommendationsFuseHolder(s) FuseHolder(s)FuseHolder(s)BAFHPFKTK-RHPS -RRSC 0-15 HPF-EEBANHPSFNQ-RHPF-RRHPS-EEKTKLP-CCSC 20 HPF-JJFNMHPS-JJFNQKTQHPS-LSC 25-30 HPF-FFFNWBBSHPF-LHPS-FFProtected by Time-Delay to 175% of Full Load CurrentOn Load Side of Motor RunningOvercurrent recommended as shown, but not by Non-Time-Delay to 300% of Full Load RecommendationsVoltsFuse(s)0-250 LPN-RK_SP, FRN-R0-600 LPS-RK_SP, FRS-R0-600 LPJ_SP, LP-CC, FNQ-R, TCFFuse RecommendationsVoltsFuse(s)0-250 KTN-R, NON0-300 JJN0-600 KTS-R, NOS0-600 JKS, KTK-R0-600 JJS203 2005 Cooper BussmannFuse Diagnostic Sizing ChartsElectric Heat (NEC 424)

2 Mains, Feeders, BranchesElectric Space HeatingSize at 125% or next size larger but in no case larger than 60amps for each subdivided Boilers with ResistanceType Immersion HeatingElements in an ASME Rated andStamped VesselSize at 125% or next size larger but in no case larger than 150amps for each subdivided RecommendationVoltsFuse(s)0-250 LPN-RK_SPFRN-R, NON0-300 JJN0-480 SC 25 to SC 600-600 LPS-RK_SPFRS-R, NOS0-600 JJS0-600 LPJ_SP, LP-CCFNQ-R, JKS, KTK-R,TCF, SC 1 2to SC 20 Feeder Circuits(600A & Less) fuse RecommendationsVoltsFuse(s)0-25O LPN-RK_SP, FRN-R0-600 LPS-RK_SP, FRS-R0-600 LPJ- SP, LP-CCMotor LoadsNo Motor LoadCombination Motor Loadsand Other Loads100% of non-continuous load plus 125% of continuous * of the FLA of largest motor (if there are two or more motors ofsame size, one is considered to be the largest) plus the sum of allthe FLA for all other motors plus 100% of non-continuous, non-motorload plus 125% of continuous, non-motor * of the FLA of largest motor (if there are two or more motorsof same size, one is considered to be the largest) plus the sum of allthe FLA for all other motors.

3 *A max. of 175% (or the next standard size if 175% does not corre-spond to a standard size) is allowed for all but wound rotor and all RecommendationsVoltsFuse(s)0-250 LPN-RK_SP, FRN-R0-300 JJN0-600 LPS-RK_SP, FRS-R0-600 JJS0-600 LPJ_SP, LP-CCJKS, KTK-RMain, Branch &Feeder Circuits(601-6000A)150% to 225% of full load current of largest motor plus 100% of fullload current of all other motors plus 125% of continuous non-motorload plus 100% of non-continuous non-motor RecommendationVoltsFuse(s)0-600 KRP-C_SP204 2005 Cooper BussmannFuse Diagnostic Sizing ChartsMotor Loads (NEC 430)Solenoids (Coils)Above 600V600V & LessFuse RecommendationsVoltsFuse(s)0-250 LPN-RK_SP, FRN-R0-600 LPS-RK_SP, FRS-R0-600 LPJ_SP, TCFFuse RecommendationsVoltsFuse(s)0-250 KTN-R, NON0-300 JJN0-600 KTS-R, NOS0-600 JJS0-600 LP-CC, JKS, KTK-RShort-Circuit OnlyBackup Overload w/ MotorStarter & Short-CircuitProtectionShort-Circuit OnlyProtected by Time-Delay FusesProtected by Non-TimeDelay Fuses & allClass CC FusesCompare the min.

4 Melting time-current characteristics of the fuses with the time-current characteristics of the overload relay curve. Thesize fuse which is selected should be such that protection is provided by the fuse and overload protection is provided by thecontroller overload RecommendationsVoltsFuse(s)2400 JCK, JCK-A, JCH4800 JCL, JCL-A, JCG7200 JCR, WKMSJ125% of motor FLA or next size of motor FLA or next size * of motor FLA or next size larger. (If 175% does not corre-spond to a standard size). If this will not allow motor to start, due tohigher than normal inrush currents or longer than normal acceleration times (5 sec. or greater), fuse may be sized up to 225%or next size of 300%* of motor FLA or next size larger (if 300% does notcorrespond to a standard size). If this will not allow motor to startdue to higher than normal inrush currents or longer than normalacceleration times (5 sec. or greater), fuses through 600 amps maybe sized up to 400% or next size Sized For:*150% for wound rotor and all DC RecommendationsVoltsFuse(s)0-250 FRN-R0-600 FRS-RFuse RecommendationsVoltsFuse(s)0-250 LPN-RK_SP0-600 LPS-RK_SPBranch CircuitFusesSize at 125% or next size RecommendationVoltsFuse(s)0-250 Best.

5 LPN-RK_SPFRN-R0-600 LPS-RK_SPFRS-R0-600 LPJ_SP, LP-CCFNQ-R, TCFS upplementaryFusesSize at 125% or next size RecommendationVoltsFuse(s)0-32 MDL 9-30A,FNM 20-30A0-125 MDA 25-30A,FNM 12-15A0-250 MDL1 16-8A,MDA2 10-20A,FNM 1 10-10A,FNW 12-30A,MDQ 1 100-7A0-500 FNQ 1 10-30A205 2005 Cooper BussmannFuse Diagnostic Sizing ChartsTransformers 600V Nominal or Less (NEC )PrimaryProtectionOnly*When 125% of FLA corresponds to astandard rating, the next larger size isnot AndSecondaryProtectionOptimum Protection125% or next size larger125% or next size larger125% or next size largerMax. of 125% or next larger*NEC MaximumsMax. 300% or next size smaller (SeeNEC (C) for control circuit trans-former maximum of 500%Max. 167% or next size smallerRated secondary current 9amps or greaterRated secondary current lessthan 9 ampsTransformerImpedance of 6%or LessRated secondary current 9amps or greaterRated secondary current lessthan 9 ampsTransformerImpedance of MoreThan 6% But LessThan 10%Rated secondary current lessthan 9 ampsRated secondary current 9amps or greaterWithout ThermalOverload ProtectionWith ThermalOverload ProtectionNote.)

6 Components on the secondary still needovercurrent protectionRated primary current lessthan 2 ampsRated primary current greaterthan or equal to 9 ampsRated primary current greaterthan or equal to 2 amps butless than 9 ampsFuse RecommendationsVoltsFuse(s)250V LPN-RK_SP, FRN-R600V KRP-C_SP, LPJ_SP, LPS-RK_SP, FNQ-R, FRS-R, TCFAABCDEFBCDEFP rimary and secondaryfuses at 125% of primaryand secondary FLA ornext size larger% of Primary FLA(or next FLA size smaller)A = 250%B = 250%C = 600%D = 600%E = 400%F = 400%% of Secondary FLAA = 167% or next size smallerB = 125% or next size larger*C = 167% or next size smallerD = 125% or next size larger*E = 167% or next size smallerF = 125% or next size larger*206 2005 Cooper BussmannFuse Diagnostic Sizing ChartsTransformers Over 600V Nominal (NEC )Solid State Devices (Diodes, SCRs, Triacs, Transistors)SupervisedInstallationsUnsup ervisedInstallationsFuse RecommendationsVoltsFuse(s)250 VLPN-RK_SP, FRN-R600 VLPS-RK_SP, LPJ-_SP,KRP-C_SP, FRS-R, FNQ-R,TCF2475 VJCD2750 VJCX2750/5500V JCW5500 VJCE, JCQ, JCY, JCU, ABWNA, AMWNA, ABWNA, SDLSJ, SFLSJ8300 VJCZ, JDZ, FFN15500 VJCN, JDN, JDM, CAV, SDM24000V24 SDM, 24 SFM, 24 FFM36000V36 CAV, 36 SDQ, 36 SFQ38000V38 CAVNote: Components on the secondary still needovercurrent protectionPrimary at code max.

7 Of 250% or nextstandard size if 250% does not corre-spond to a standard ratingPrimaryProtectionOnlyTransformerIm pedance Less Thanor Equal to 6%Primaryat codemax. of300%SecondaryOver 600 VSecondary atcode max. of250%Secondary atcode max. of250%Secondary atcode max. of225%SecondaryOver 600 VPrimaryat atcode max. of250%SecondaryOver 600 VPrimary at code max. of 300%or next standard size if 300%does not correspond to astandard ratingTransformerImpedance Less Thanor Equal to 6%Primary at code max. of 300%or next standard size if 300%does not correspond to astandard ratingSecondaryOver 600 VSecondary at code max. of125% or next standard size if125% does not correspond toa standard ratingSecondary at code max. of225% or next standard size if225% does not correspond toa standard ratingSecondary at code max. of125% or next standard size if125% does not correspond toa standard ratingSecondary at code max. of250% or next standard size if250% does not correspond toa standard ratingTransformerImpedance GreaterThan 6% But LessThan 10%Secondary600V orBelowSecondary600V orBelowPrimary andSecondaryProtectionTransformerImpedan ce GreaterThan 6% But LessThan 10%Secondary600V orBelowSecondary600V orBelowShort-CircuitProtection Only F, S, K, & 170M Series fuses sized up to several sizes largerthan full load RMS or dc rating of RecommendationsVoltsFuse(s)0-130 FWA0-250 FWX0-500 FWH0-600 FWC, KAC, KBC0-700 FWP, 170M Series, SPP0-1000 FWJ, 170M Series, SPJ207 2005 Cooper BussmannFuse Sizing GuideBuilding Electrical SystemGeneral guidelines are given for selecting fuse amp ratings for most circuits.

8 Somespecific applications may warrant other fuse Sizing ; in these cases the load characteristics and appropriate NEC sections should be considered. The selections shown here are not, in all cases, the maximum or minimum amp ratingspermitted by the NEC . Demand factors as permitted per the NEC are notincluded in these AmpsFeederWithCombin-ationMotorAnd NonMotorLoadMotorStarterOver-LoadsRelays LargeMotorContinuousLoadsLightingHeating NonContinuousLoadsPowerFactorCorrectionC apacitorContinuousLoads55579 FeederWithAllMotorLoadFeederWithNoMotorL oad7755 fuse Recommendations601 to 6000A Low-PeakTime-Delay FuseKRP-C_SP1/10to 600A Low-PeakDual-Element, Time-Delay FusesLPN-RK_SP(250V); LPS-RK_SP(600V) orLPJ_SP (600V)FusetronDual-Element FusesFRN-R (250V); FRS-R (600V)10. Transformer Primary fuse (without secondary fuse protection). When transformer primary current is equal to or greater than 9 amps, the dual-element,time-delay fuse should be sized at 125% of transformer primary current or thenext size larger.

9 Note: Secondary conductors must be protected from Transformer Primary fuse (with secondary fuse protection). May be sized at250%of transformer primary current if,12. The secondary fuse is sizedat no more than 125%of secondary full-load current. Note: Secondary conductors must be protected at their and all Class CC Fuses (JKS, KTS-R,KTN-R, JJS, JJN, LP-CC, KTK-R, and FNQ-R)1. Main fuse according to method in Feeder Circuit With No Motor fuse size must be at least 125%ofthe continuous load plus 100%of the non-continuous load. Do not size largerthan the ampacity of the Feeder Circuit With All Motor the fuse at 300%of the full-load current of the largest motor plus the full-load current of all other motors. Do notsize fuse larger than the conductor Feeder Circuit With Mixed fuse at sum of:a. 300%of the full-load current of the largest motor plusb. 100%of the full-load current of all other motors plusc.

10 125%of the continuous, non-motor load plusd. 100%of the non-continuous, non-motor Branch Circuit With No Motor fuse size must be at least 125%ofthe continuous load plus 100%of the non-continuous load. Do not size largerthan the ampacity of conductor.*6. Motor Branch Circuit With Overload the fuse as close to but notexceeding 300%of the motor running full load current. Provides ground fault andshort-circuit protection Motor Branch Circuit With fuse Protection fuses cannotbe sized close enough to provide motor running overload protection. If sized formotor overload protection, non-time-delay fuses would open due to motor startingcurrent. Use dual-element Ampacity Selection1. Feeder Circuit And Main Circuit With Mixed ampacity atleast sum of:a. 125%of continuous non-motor load plusb. 100%of non-continuous non-motor load plusc. 125%of the largest motor full-load current plusd. 100%of all other motors' full-load Feeder Circuit With No Motor ampacity at least 125%of thecontinuous load plus 100%of the non-continuous Feeder Circuit With All Motor ampacity at least 125%of thelargest motor full-load amps plus 100%of all other motors full-load Feeder Circuit With Mixed according to method 1 Branch Circuit With No Motor ampacity at least 125%of thecontinuous load plus 100%of the non-continuous , 7, & 8.