Sizing generator conductors

[brian ploskunak]

I have an oversized 150 KW generator feeding a 400 amp breaker in a MTS at a gas station. The service is 120/240, 1 phase. Is there something that says I can size the feeders to the 400 amp breaker or do I have to size them for the full load (625 amps) of the generator as stated in section 445.13?

 

[RUWired]

Is there something that says I can size the feeders to the 400 amp breaker or do I have to size them for the full load (625 amps) of the generator as stated in section 445.13?

Brian , You need to protect the feeder conductors at their supply.If the generator supply breaker is 625, you need to size them to that.Nothing says you can't install another ocpd next to the generator and protect the conductors and their ampacity.Also, 445.13 are for the conductors from the generator to the first ocpd which is usually at the generator.If no ocpd is at the generator then 445.13 applies up to the first protection device.
Rick

 

[brian ploskunak]

That's what I thought originally, but 445.13 threw me off a little. Thanks, Rick, for the clarification.