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AccomplishedEnergy24 t1_jaepn1h wrote

Reply to comment by WealthyMarmot in Adding outside GFCI by Unlikely_Play

You actually can't safely share a neutral between two different GFCI's with different hots, and run them to separate breakers - the neutral here will carry the difference between the two hots (and even if that was safe, it would trip the GFCI). The proper way to do it is a dual pole GFCI breaker.

This is the only safe way to get 2 15/20 amp GFCI protected circuits out of this situation. This is a standard MWBC application.

If you share a breaker, there is no point to using multiple GFCI's, may as well use one and run the other downstream, and ignore the extra hot.


WealthyMarmot t1_jaeqi3w wrote

They're not separate breakers. If my understanding is correct, it's just a single-pole, but someone ran a 12/3 from a switch to outside so that there's an optional switched hot in case someone wants to install a switched outlet (like OP does). The hots are on the same phase, unlike a MWBC.

Two GFCIs should work totally fine here. The neutral at each outlet is clean.


AccomplishedEnergy24 t1_jaerdxk wrote

Yes, if he runs them to the same breaker, it would be fine. But also pointless to GFCI both of them in that case. You can still switch the outlet with a single GFCI and GFCI protect both outlets if you want.


WealthyMarmot t1_jaermui wrote

If he wants to switch one and not the other, he needs to GFCI both. The best way would be a GFCI breaker but I don't usually recommend homeowners open their panels.


AccomplishedEnergy24 t1_jaewucc wrote


single pole GFCI breaker is not materially different than switching the load side of a single GFCI since he has a shared neutral and single shared breaker.

If it was a double pole GFCI and two circuits it would be different.

But in this single pole config, the circuit can't tell whether you have a GFCI breaker and switch the load downstream, or use a regular breaker + GFCI outlet and switch the load downstream of that.

It's the same exact circuit. You've just separated "thing providing overcurrent protection" from "thing detecting ground fault" instead of putting them in a single thing.

IE a GFCI breaker is the same as if you used a regular breaker and ran it all to a GFCI outlet next to the panel, and then ran everything downstream of that including the switch.

Switching in any of these cases (GFCI breaker, single GFCI + load switched beyond that, shared neutral and two GFCI's, etc) will likely cause nuisance trips, though the two former will probably be way worse than the latter.


Yowomboo t1_jaezj0d wrote

OP doesn't appear to want to run any new wire. Switching after the GFCI would require new wire. Swapping in a breaker solves this problem. However not being an electrician I don't know if swapping in a GFCI breaker could cause any other issues.

Given that OP is asking such a question I definitely wouldn't recommend they swap a breaker. They should 100% contact an electrician.

Edit: Just realized what you were getting at. Assuming OP could find an outlet that comes before the switch/outlet combo he could 100% swap that with a GFCI outlet. Again given the way this question is being asked with no additional information OP should call an electrician.