GE Industrial Solutions Guide to Low Voltage System Design and Selectivity DET-654C DET-654C
Contents Foreword . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2 National Electric Code Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Foreword GE’s application publications on instantaneous selectivity, Guide to Instantaneous Selectivity (DET-760), available in the Publications Library at www.geelectrical.com) lists GE low voltage circuit breakers and the short circuit current to which they are selective. DET-537 includes legacy products, and is built essentially around the capabilities of the MicroVersaTrip Trip Unit utilized in GE devices for many years.
DET-654C Guide to Low Voltage System Design and Selectivity Introduction Introduction What What is is selectivity? selectivity? The electrical design industry has historically required electrical system circuit breaker The electrical design industry has historically required electrical system circuit selections and settings be validated with a short circuit and coordination study performed breaker selections and settings be validated with a short circuit and coordination by a licensed engineer.
DET-654C These requirements state that overcurrent protective devices (OCPD) must be “fully selective.” In other words, given the range of available interrupting currents, any given pair of overcurrent devices covered by the NEC Articles referenced above must behave in a coordinated fashion as defined in NEC Article 100: “Coordination (Selective).
Guide to Low Voltage System Design and Selectivity DET-654C The first words of NEC, Article 90.1, Purpose, are: “(A) Practical Safeguarding. The purpose of this Code is the practical safeguarding of persons and property from hazards arising from the use of electricity. This Code is not intended as a design specification or an instruction manual for untrained persons” Historically, the NEC started by establishing protection requirements for low voltage loads, cables, transformers, etc.
DET-654C 4000A 4000A CURRENT IN AMPERES GF GF Traditional system designs would size the 250A OCPD to 600A or possibly 800A, panels of declining ampacities, i.e., a series of progressively smaller electrical distribution Some traditional electrical system designs have utilized a “waterfall” of electrical panels connected to larger upstream panels. This concept is popular because it allows the distribution panels of declining ampacities, i.e.
DET-654C ampere feeder is feeding threethree downstream panels.panels. With theWith use of riser In Figure Figure3,3,the the400 400 ampere feeder is feeding downstream the panels thepanels same ampacity, only ampacity, two layers of selective breakers would be needed. If a use of of riser of the same only two layers of selective breakers traditional design strategy of progressively subpanels had been used, foursublayers of would be needed.
Guide to Low Voltage System Design and Selectivity DET-654C Automatic Transfer Switch (ATS) Protection Transformer / Current Limiting Reactor Applications Most ATSs built for use in North America are manufactured in accordance with the UL 1008 standard, which references UL 489 for molded case circuit breakers. Furthermore, many ATS manufacturers provide application data specifying which MCCBs are appropriate for protecting the ATS ampacity and short circuit withstand ratings.
DET-654C • For systems with 35kA short circuit current or less: – U tilize an LVPCB with ArcWatch I-ZSI as the service entrance main as the fifth and top layer of selective protection. – Utilize PB II as the fourth layer of selective protection. – Utilize Spectra K MCCB as the third layer of selective protection. – Utilize FG MCCB as the second layer of selective protection.
DET-654C Arc Flash Considerations At the core of fully selective designs based on NEC Coordination (fully selective) requirements is the concept of coordination of circuit breaker OCPD time-current characteristics. Practically, this means that the circuit breaker immediately upstream of the breaker closest to the fault will be set (delayed or desensitized) to prevent it from operating until the downstream breaker clears the fault.
DET-654C Guide to Low Voltage System Design and Selectivity Selective Low Voltage Circuit Breakers Pairing Diagram WP OR ENTELLIGUARD 1200-5000A (WITHOUT INST. OR WITH ArcWatch I-ZSI) Figure 4 PB2, WP, ENTELLIGUARD 800A (W/INST.) PB2, WP, ENTELLIGUARD 1600A (W/INST.) PB2, WP, ENTELLIGUARD 2000A (W/INST.
DET-654C DET-654C Guide to to Low Low Voltage Voltage System System Design Design and and Selectivity Selectivity Guide GE Circuit Breaker / Equipment Combinations Table 1 Equipment Breakers Main Feeder A-Series II Switchboards Switchgear Panelboards Enclosure A-Series II Spectra Mounted AQ AE AD AS Powerpanel Powerpanels Spectra AV-3 PB II Evolution AKD10 Entellisys (1) AKD20 WavePro without IOC WavePro with IOC EntelliGuard G without IOC EntelliGuard G with IOC Power Break II Spectra K Record Plus F
Guide to Low Voltage System Design and Selectivity DET-654C Appendix 1. A chieve full selectivity (LT, ST and IOC) between each pair of circuit breakers applied 2. P rovide required NEC transformer protection 3. P rovide recommended ANSI through fault protection of transformers 4.
Guide to Low Voltage System Design and Selectivity DET-654C Riser Diagram Showing Typical Selective Combinations UTIL-0001 Rated MVA 1000.0 MVA Rated Voltage 13200 V X/R 3P 8.000 X/R SLG 8.000 Figure 5 P S XF2-0001 FullLoad kVA 1500.0 kVA Pri Rated Voltage 13200 V Sec Rated Voltage 480 V Z% 5.7500% BUS-0004 480 V Isc 3P 30580 A CBL-0001 PD-0001 GE SS Sensor/Trip 1600.0 A Plug 1600.0 A PD-0002 GE FGH Sensor/Trip 250.0 A Plug 100.0 A PD-0003 GE FGH Sensor/Trip 250.0 A Plug 100.
Guide Guide to to Low Low Voltage Voltage System System Design Design and and Selectivity Selectivity DET-654C Riser Diagram Showing Typical Selective Combinations UTIL-0001 Rated MVA 1000.0 MVA Rated Voltage 13200 V X/R 3P 8.000 X/R SLG 8.000 Figure 6 P S XF2-0001 FullLoad kVA 1500.0 kVA Pri Rated Voltage 13200 V Sec Rated Voltage 480 V Z% 5.7500% BUS-0004 480 V Isc 3P 30580 A CBL-0002 PD-0008 GE UL-Tier N-Env 1 Sensor/Trip 1600.0 A Plug 1600.0 A PD-0010 GE SKSC Sensor/Trip 800.0 A Plug 400.
Guide to Low Voltage System Design and Selectivity DET-654C 18 A 100K 10K 10 1K 5 100 CURRENT IN AMPERES 35kA MAX AT LOCATION OF PRIMARY OCPD UTIL-0011 Isc 3P 60000 Amps 1000 RANGE 100 TO 600 TR 11 UPSTREAM SMALLEST GE FG Record Plus, SMR2 Frame/Model FGN Sensor/Trip 250 A Plug 100 A AIC 65 kA Settings LTPU / LTD Fixed (100A) ; 1.25 STPU (1.5-12 x LTPU) 9X (900A) STD (0.04 - 0.42s) 0.42 (I^2t In) INST (2 - 13.5 x S) 13.5X (3375A) 100 TR-11 15.0 kVA Z% 3.
Guide to Low Voltage System Design and Selectivity DET-654C 36 A UTIL-0013 Isc 3P 60000 Amps 100K 10K 10 1K 5 100 CURRENT IN AMPERES 65kA MAX AT LOCATION OF PRIMARY OCPD 1000 Range 125 to 250A TR 13 UPSTREAM SMALLEST GE FG Record Plus, SMR2 Frame/Model FGN Sensor/Trip 250 A Plug 125 A AIC 65 kA Settings LTPU / LTD Fixed (125A) ; 2.5 STPU (1.5-12 x LTPU) 12X (1500A) STD (0.04 - 0.42s) 0.42 (I^2t In) INST (2 - 13.5 x S) 13.5X (3375A) 100 AD PANEL L13 LARGESTB GE THQB Trip 30.
Guide to Low Voltage System Design and Selectivity DET-654C UTIL-0015 Isc 3P 60000 Amps 100K 10K 10 1K 5 100 CURRENT IN AMPERES SPECTRA PP 1000 54 A TR15 UPSTREAM GE FG Record Plus, SMR2 Frame/Model FGN Sensor/Trip 600 A Plug 600 A AIC 65 kA Settings LTPU / LTD Fixed (600A) ; 1.25 STPU (1.5-10 x LTPU) 9X (5400A) STD (0.04 - 0.42s) 0.04 (I^2t Out) INST (2 - 11 x S) 11X (6600A) 65kA MAX AT LOCATION OF PRIMARY OCPD TR-15 45.0 kVA Z% 4.
Guide to Low Voltage System Design and Selectivity DET-654C 90 A UTIL-0017 Isc 3P 60000 Amps 100K 10K 10 1K 5 100 CURRENT IN AMPERES 1000 TR 17 UPSTREAM GE FG Record Plus, SMR2 Frame/Model FGN Sensor/Trip 600 A Plug 600 A AIC 65 kA Settings LTPU / LTD Fixed (600A) ; 1.25 STPU (1.5-10 x LTPU) 10X (6000A) STD (0.04 - 0.42s) 0.
Guide to Low Voltage System Design and Selectivity DET-654C 100K 10K 10 1K 5 100 CURRENT IN AMPERES UTIL-0018 Isc 3P 60000 Amps 1000 18 A Range 100-250 65kA MAX AT LOCATION OF PRIMARY OCPD TR18 UPSTREAM GE FG Record Plus, SMR2 Frame/Model FGN Sensor/Trip 250 A Plug 100 A AIC 65 kA Settings LTPU / LTD Fixed (100A); 1.25 STPU (1.5-12 x LTPU) 10X (1000A) STD (0.04 - 0.42s) 0.42 (I^2t In) INST (2 - 13.5 x S) 13.5X (3375A) 100 TR-18 15.0 kVA Z% 3.
Guide to Low Voltage System Design and Selectivity DET-654C UTIL-0022 Isc 3P 60000 Amps 100K 10K 10 1K 5 100 CURRENT IN AMPERES 1000 135 A TR22 UPSTREAM GE SK, MET, EXT Frame/Model SKTC Sensor/Trip 800 A Plug 600 A AIC 65 kA Settings LTPU (0.5-1 x RP) 1.00X (600A) ; C-6 STPU (1.5-9 x LTPU) 8X (4800A) STD Min (ST01 - ST12) ST01-Min (I^2t Out) HSSTOC Fixed (12000A) INST EXT (2-25.5 x S) 25.5X (20400A) HSIOC Fixed (37620A) 65kA MAX AT LOCATION LOCATION OF PRIMARY OCPD 100 TR-22 112.5 kVA Z% 5.
Guide to Low Voltage System Design and Selectivity DET-654C CURRENT IN AMPERES 100K 10K 10 1K 5 100 UTIL-0020 Isc 3P 60000 Amps TR-20 112.5 kVA Z% 5.0000 % L20A BRANCH GE THQB Trip 30.0 A TR20 UPSTREAM SMALLEST GE SK, MET, EXT WITH ZSI Frame/Model SKTC Sensor/Trip 800 A Plug 800 A AIC 65 kA Settings LTPU (0.5-1 x RP) 1.00X (800A) ; C-4 STPU (1.5-9 x LTPU) 9X (7200A) STD Min (ST01 - ST12) ST01-Min (I^2t Out) HSSTOC Fixed (12000A) INST EXT (2-25.5 x S) 25.
Guide to Low Voltage System Design and Selectivity DET-654C CURRENT IN AMPERES 100K 10K 10 1K 5 100 UTIL-0008 Isc 3P 60000 Amps SPP 1000 180 A TR-8 UPSTREAM GE SK, MET, EXT WITH ZSI Frame/Model SKTC Sensor/Trip 1200 A Plug 1200 A AIC 65 kA Settings LTPU (0.5-1 x RP) 1.00X (1200A) ; C-2 STPU (1.5-9 x LTPU) 9X (10800A) STD Min (ST01 - ST12) ST01-Min (I^2t Out) HSSTOC Fixed (12000A) INST EXT (2-17 x S) 17X (20400A) HSIOC Fixed (37620A) 100 SPP TR-8 150.0 kVA Z% 3.
Guide to Low Voltage System Design and Selectivity DET-654C CURRENT IN AMPERES 100K 10K 10 1K 5 100 UTIL-0021 Isc 3P 60000 Amps TR-21 150.0 kVA Z% 3.6000 % L21C LARGEST GE THHQB Trip 30.0 A SPP TR-21 PRIMARY FEEDER GE FG Record Plus, SMR2 Frame/Model FGH Sensor/Trip 600 A Plug 300 A AIC 100 kA Settings LTPU / LTD Fixed (300A) ; 1.25 STPU (1.5-10 x LTPU) 10X (3000A) STD (0.04 - 0.42s) 0.
Guide to Low Voltage System Design and Selectivity DET-654C CURRENT IN AMPERES 100K 10K 10 1K 5 100 UTIL-0031 Isc 3P 60000 Amps SPECTRA SWBD MAIN - WITH IZSI TR-31 UPSTREAM SMALLEST GE Entelliguard G ICCB, EGTU, ZSI Frame/Model UL-Tier N-Env 1 Sensor/Trip 1600 A Plug 1600 A AIC 65 kA Settings LTPU/LTD (0.5-1 x RP) 1.00X (1600A) ; C-2 STPU (1.5-12 x LTPU) 6.5X (10400A) ZSI (ST01- ST11) ST05-Min (I^2t Out) ZSI INST(2-15 x RP) 8.5X (13600A) Override (HSIOC) Fixed (44940A) 1000 100 TR-31 225.
Guide to Low Voltage System Design and Selectivity DET-654C CURRENT IN AMPERES 100K 10K 10 1K 5 100 UTIL-0031 Isc 3P 60000 Amps SPECTRA SWITCHBOARD MAIN WITH IZSI TR-31 UPSTREAM SMALLEST GE Entelliguard G ICCB, EGTU, ZSI Frame/Model UL-Tier N-Env 1 Sensor/Trip 1600 A Plug 1600 A AIC 65 kA Settings LTPU/LTD (0.5-1 x RP) 1.00X (1600A) ; C-2 STPU (1.5-12 x LTPU) 6.5X (10400A) ZSI (ST01- ST11) ST05-Min (I^2t Out) ZSI INST(2-15 x RP) 8.5X (13600A) Override (HSIOC) Fixed (44940A) 1000 TR-31 225.
Guide to Low Voltage System Design and Selectivity DET-654C 100K 10K 10 1K 5 100 CURRENT IN AMPERES UTIL-0112 Isc 3P 60000 Amps 1000 SPECTRA SWITCHBOARD MAIN WITH IZSI TR111 UPSTREAM GE Entelliguard G ICCB, EGTU, ZSI Frame/Model UL-Tier N-Env 1 Sensor/Trip 1600 A Plug 1600 A AIC 65 kA Settings LTPU/LTD (0.5-1 x RP) 1.00X (1600A) ; C-3 STPU (1.
Guide to Low Voltage System Design and Selectivity DET-654C CURRENT IN AMPERES SPECTRA SWITCHBOARD MAIN WITH IZSI 100K 10K 10 1K 5 100 UTIL-0112 Isc 3P 60000 Amps TR111 UPSTREAM GE Entelliguard G ICCB, EGTU, ZSI Frame/Model UL-Tier N-Env 1 Sensor/Trip 1600 A Plug 1600 A AIC 65 kA Settings LTPU/LTD (0.5-1 x RP) 1.00X (1600A) ; C-3 STPU (1.
Guide to Low Voltage System Design and Selectivity DET-654C Glossary Abbreviations AHJ AIC ATS FTL ICCB IOC kA LVPCB MCCB MCS NEC OCPD V xfmr Authority having jurisdiction Amperes interrupting current Automatic transfer switch Feed through lugs Insulated case circuit breaker (UL Standard 489 rated) Instantaneous overcurrent Kilo-amperes Low Voltage Power Circuit Breaker (ANSI Standard C37.
This information is based on data available at the time of printing and is believed to be accurate, but GE makes no warranty or guarantee regarding the accuracy of the information. DET-654C (Revision C) supersedes but does not invalidate ratings obtained from all prior revisions of DET-654. After June 2014, DET-654C should be used exclusively to obtain new ratings. GE Industrial Solutions 41 Woodford Avenue Plainville, CT 06062 www.geindustrial.
