Generator

[SheppardJ]

I have an application for permit in right now and inspector called me yesterday with a concern. We are using one generator to feed 2 - 200amp services on one building. Coming out of the generator we are installing two - 200 enclosed breakers which then feed my transfer switches. He is telling me that since my generator has a 250a breaker in it that my 2 enclosures housing the 200 amp breakers must be rated for at least 250 amps since they are the first thing in line. Unfortunately he can not provide me with a code reference for that. Any ideas? It would not be a big deal except it over doubles the cost of these items.

 

[Smart $]

He's not going to find Code that prohibits something that is not prohibited. As long as your conductors between the 250A breaker and the 200A breakers are properly sized, you are completely compliant. Under the same criteria just stated, you could substitute the 200A breakers with any different ampere rating and be compliant. Proper sizing the conductors is either for the 250A breaker or as taps under 240.21(B).

If I were the inspector (plan reviewer) I'd be more concerned with whether the generator can supply the load or not.