I know the code NEC 240.4(b) will allow the next size up. So you can supply a 400A breaker with 500kCMIL CU conductors. I have a 100% rated circuit breaker with 500kCMil conductors - is that code compliant?
Since the cable ampacity is 380A and the next breaker ampere rating is 400A, it should comply (as also mentioned by wareagle).
But the conditions are:
(1) The conductors are not used for specific applications as defined in NEC section 240.4(G)
(2) The breaker is NEC compliant. It is not clear you indicated IEC breaker with 100% rated
- MS
__________________
"All my technical advices in this forum must be consulted with and approved by a local registered professional engineer before implementation" - Mohammed Samad (Linkedin Profile: http://www.linkedin.com/in/msamad)
Just want to state that if you have circuit breaker carrying large currents or high voltages (440V AC and above), you should take the safety warnings seriously about turning them on or off causing a flash-over. At the lab I work at a guy wound up being air flighted out with 2nd degree burns and pieces of metal embedded in him when this occurred with a 440V circuit breaker. I used to think the precautions were overkill/silly before this when the lab limited people who could mess with these to be wearing clothes that don't burn (cotton, wool, silk), eye protection and leather gloves to protect hands and arms until this happened. I no longer bemoan the safety requirements they place on us.
400A, 100% Rated Circuit Breaker
Re: 400A, 100% Rated Circuit Breaker
