I have done electrical work and wired subpanels before. The house I am working on has a 400 amp service, distributed in 2 breaker boxes with a 200 amp main breaker in each. There are multiple heating and AC units and water heaters divided across the two breaker boxes.

I would like to add a subpanel and have it wired to both, so the load from the subpanel is distributed evenly across both 200-amp boxes instead of being confined to one. It sounds kind of questionable from a codes or best practices standpoint, since the feed from each main box would essentially be in parallel with the feed from the other main box.

Is this a viable option, or should I simply install a separate subpanel off each box and distribute the new circuits between the two?

Thanks for your help.

No, this is NOT a viable option, just don't ask me to quote a code section right this minute. I'd have to find it.


The load WILL be balanced across the 400A service, it's just that one panel will have more of a load on it. This is not at all uncommon. Just reserve future loads for the other panel.

Right, that's what I was trying to do - equalize the load across the panels. Guess I'll have to drop that idea. Thanks for your answer.