Installing a 100 amp breaker in a 200 amp panel

[Mike Lamb]

This panel is using a copper 1 AWG at a 200 amp main disconnect. The service entrance pipe is going to be too small for 3/0.  This house does not need a 200 amp main. Will it be a problem to put 100 amp main into this 200 amp panel slot?

[Marc]

You'll need to ask your local (Challenger) electrical wholesaler if a 100 will fit in place of a 200 in that particular model of panel.  I think there's a decent chance of finding a 175 or less that will work. 1/0 is ok on a 175 A service.

I'd do a load analysis first to find out just how big a service you'll need.  The NEC has instructions for doing that.  That's more up a sparky's alley than an HI's though.

Edited July 12, 2017 by Marc

[Mike Lamb]

Isn't 1/0 AWG different from 1 AWG?

[Marc]

Yes, 1/0 AWG is one size larger than 1 AWG.

Dang, now I see my mistake.  OK, a 150 A breaker or smaller will work once you confirm the actual load with a load analysis.

Sorry.

[Mike Lamb]

Thanks.