Can I back feed my panel with a lower amp breaker than the service inlet?

Question

I believe I can run my whole house off my current generator 3500W/4000Max if I don't use the electric stove and oven. The generator subpanel has power meters for both legs, which, even when my oil burner and fridge are running, never indicates higher than about 1500W load.

I currently have a generator subpanel fed by (A)60A breaker w/ 6AWG wire in main panel and (B)L14-30 input with 10AWG feeder from 3500W/4000Max Generator. I'd like to remove the generator feed from the subpanel, and rather backfeed a 30A breaker on the main panel with the same 10AWG feeder. I haven't looked for an appropriate main breaker interlock for my panel, but I am aware that I will need one for this application.

Other than the obvious "you can't run your house off 30A", is there any code reason that the main panel can't be backfed by an interlocked breaker?

Answer 1

If you have an interlock it would be legal to run your home off your generator. The only issue I can see would be if two much stuff was turned on it could overload your generator.

Answer 2

Yeah, there's one big issue you may run into: separation of neutral and ground. This is one reason generator subpanels can be nice, some of them provide for switching neutral.

You can only have one neutral-ground bond in a system. The problem is that many smaller generators of that size provide their own neutral-ground bond, because they are meant to be portable and not a house backup.

So that N-G bond on the generator would have to be temporarily removed.

Also, it is not uncommon for units of this size to have GFCI protection. That definitely will not play well with two neutral-ground bonds, as that will be considered a ground fault.