Branch breaker kAIC rating

[sbutler]

I thought the code required branch breaker ratings to be the same or more than the main but cant find it.

Thanks for any feedback.

 

[jim dungar]

I thought the code required branch breaker ratings to be the same or more than the main but cant find it.

Thanks for any feedback.

110.09 requires devices to be rated, have appropriate AIC, for the fault current available at their line side terminals. There is no code requirement for how one device is rated versus any other device.

Then you can get into the whole series ratings issues, where the branch device absolutely can be lower than the main.