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Standalone application

I have a 4 wire 240V Generator going to a 2pole 120/240V rated breaker,

  • One pole feeds Line side Hot of #1 GFCI
  • Other pole feeds Line side Hot of #2 GFCI

The wiring between breaker and receptacle for each hot is 14awg.

I was planning to configure gen in parallel 120V, combine the neutrals of each winding and bond it to ground, not through a breaker, have combined neutral go to #1 GFCI receptacle Line side Neutral with 10awg, then daisy chain to the #2 GFCI receptacle Line side Neutral with 14awg from #1 GFCI Line side Neutral.

I was going to try daisy chaining the grounds together for each GFCI too, but can't get terminals that will fit the receptacle correctly to allow for this, so will end up running each back to ground block. Is there anything wrong with daisy chaining them in relation to the GFCI functionality?

When I load both receptacles at the same time, are the GFCI going to trip due to neutral balance? Is there anything inherently wrong with this? Trying to save wire due to lack of junction points.

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  • Seems complicated. Most 240v generators already have one or two 120v breaker/fuse protected outlets. All you should need is a heavy gauge(14 or 12) extension cord.
    – crip659
    Commented May 31, 2022 at 23:17
  • Why are you proposing to configure the generator windings "in parallel 120V"? What loads do you want to power (voltages and amperages)?
    – nobody
    Commented May 31, 2022 at 23:25

1 Answer 1

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You can't ever daisy-chain grounds

With safety ground wire, you are not allowed to use the device as a splice point. You must pigtail the ground to the device. That is so that if you remove the device, the ground is still continuous and continues to protect the downline circuit.

I know it's an assembly inconvenience and the Europeans think we're nuts, but it's required here.

GFCIs don't care what you do on the Line side.

The GFCI mechanism doesn't know you shared neutral on the line side.

But Code cares

What you're trying to do there is called a MWBC or Multi-Wire Branch Circuit.

Anytime you are at a point where both hots are present, the ground rules apply to neutral: You cannot use the device as a way to splice the neutral wire. You must pigtail.

Same basic reason: removal of the device must not interrupt neutral for the other half of the circuit, which is still using it!

I was going to try daisy chaining the grounds together for each GFCI too, but can't get terminals that will fit the receptacle correctly to allow for this, so will end up running each back to ground block. Is there anything wrong with daisy chaining them in relation to the GFCI functionality?

GFCI devices don't use ground for anything at all. Well, GFCI+receptacle combo devices use ground for the receptacle, but the GFCI doesn't connect to it.

You can't get terminals like that because, code violation.

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  • @nobody -- you can't daisy-chain neutrals period on a MWBC, for the reason Harper describes -- has nothing to do with GFCIs Commented Jun 1, 2022 at 3:50

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