- Engine:
- 3406B (S/N: 2WB1-11475; 4JK1-0098; 4PM1-UP; 4RG1-1501)
- 3406C (S/N: KPS1-UP; PFH1-UP; 2WB11476-UP; 4JK0099-UP; 4RG1502-UP; 4ZR1-UP; 8FS1-UP)
- 3406E (S/N: 9NN1-UP)
- 3412 (S/N: 2WJ1-UP)
- 3412C (S/N: BAK1-UP; BAX1-UP; BCW1-UP; 1EZ1-UP; 2SZ1-UP; 3FZ1-UP; 9EP1-UP)
- 3456 (S/N: BGA1-UP; CBX1-UP; CCB1-UP; EPE1-UP; GHJ1-UP)
- 3508 (S/N: CAW1-UP; CNF1-UP; PTK1-UP)
- 3508B (S/N: BGX1-UP; CNB1-UP; PTN1-UP)
- 3512 (S/N: CMJ1-UP; FDR1-UP; PTG1-UP; PTH1-UP)
- 3512B (S/N: BLF1-UP; BRK1-UP; CMC1-UP; PTF1-UP; PTM1-UP)
- 3516 (S/N: CAL1-UP; CMD1-UP; PTD1-UP)
- 3516B (S/N: BMB1-UP; BPJ1-UP; CPA1-UP; FDN1-UP)
- G3406 (S/N: KAR1-UP)
- G3412 (S/N: KAP1-UP)
- G3508 (S/N: CPJ1-UP; CPS1-UP; CPY1-UP)
- G3512 (S/N: CRN1-UP; CSP1-UP)
- G3516 (S/N: CME1-UP; CSZ1-UP)
- G3516B (S/N: CSC1-UP)
Resetting or closing a circuit breaker after the circuit breaker trips may be difficult and may lead to the circuit breaker being replaced unnecessarily. The circuit breaker, being a robustly tested and UL Listed device, is rarely the root cause of undesired performance.
Listed below are some steps to consider before deciding to replace a circuit breaker. When the steps below are followed, a more accurate diagnosis will be made and circuit breakers will be replaced only when necessary.
- Determine what the ambient operating temperature and the connected load were when the circuit breaker was tripped or was opened.
Note: In this case, ambient temperature is defined as the temperature of the air immediately surrounding the circuit breaker.
- Determine the actual circuit breaker trip point by applying any ambient operating temperature and operating altitude derating factors. Then, determine whether the circuit breaker is properly sized and applied.
- Before attempting to reset the circuit breaker, allow ample cooling time after tripping or opening the circuit breaker.
- Before attempting to reset the circuit breaker, clear any genset package faults being detected by the generator set controller (GSC).
- Determine whether there are any load-induced overloads or faults. Isolate any load-induced overloads or faults from the circuit before attempting to reset the circuit breaker. Disconnect all load cables from the circuit breaker in order to make a positive determination.
- Inspect the shunt trip mechanism for proper installation, wiring, and operation.
- Determine the correct instantaneous and time delay trip settings. Ensure that the solid state trip unit is set properly.
Note: Most circuit breakers are shipped from the manufacturer with minimal settings installed as defaults. Proper settings are determined through careful system and coordination analyses.
- Determine the load harmonic content and whether the load is continuous.
Note: Harmonics generated by certain electronic loads can triple the phase currents seen by the circuit breaker and may cause the circuit breaker to trip unexpectedly. Continuous loads, those operating for more than three hours, will require either a 100% rated circuit breaker or an oversized 80% rated circuit breaker with properly sized load conductors.