How to upgrade generator socket from 20A to 30A

generator

I just replaced a 20A generator with a 30A one, and I need to upgrade the generator socket.

The context is a 100% off-grid cabin with two solar panels, a small battery bank, and a 120VAC inverter feeding a few circuits in the house. The generator is used for backup power and to pump water using a 240VAC well pump. Here's the existing setup:

Generator with 20A breaker => 20A cable => L14-20 socket => 12 AWG cable directly to bus bars on a dedicated 100A-rated 8-position panel (Square-D QO Load Center model QO6-12L100DF/S). This panel has two breakers: 20A 1-pole that feeds inverter-charger, 20A 2-pole that feeds the well pump. When I want to charge the batteries, I turn on the generator and flip the relevant breaker; same when I want to pump water. (This was all installed by a licensed electrician who specializes in off-grid work, and it works well.)

All I think I have to do is adjust as follows:

Generator with 30A breaker => 30A cable => L14-30 socket => 10 AWG cable => existing 8-position panel.

Questions:

  • Is this correct?
  • The existing 20A breakers and the downstream wiring to the inverter-charger and well pump can just be left as is, right?
  • My preference would be to add a 30A 2-pole breaker and feed the wiring from the generator through it instead of connecting directly to the bus bars. That way I would have an interior shutoff (in addition to the 30A breaker on the generator itself). Are there any issues with doing that?

Best Answer

Go ahead and put the 30A breaker in, along with a hold down kit

The good news is that your plan with the 30A breaker is feasible, given that you don't have a utility service, which means you aren't subject to the new 230.85 emergency disconnect requirements, which'd require an outdoor disconnect switch or main breaker. However, you'll need a PK2MB hold-down kit for your 30A breaker in order to comply with NEC 408.36(D) (and keep someone from accidentally yanking out a live breaker during maintenance); fortunately, these are not hard to come by.

P.S. your panel is only a six-position panel, which means you'll have only one space left for breakers in it after you put the 30A breaker in, unless you resort to "double-stuff" breakers that is.

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