Filthy Phil
Member
Will a two GFCI's on two seperate circuits work properly if they are sharing the same neut (multi wire circuit). I was told that they won't reset after being tested.
Multi Circuit with GFCI
- Thread starter Filthy Phil
- Start date
- Status
- Location
- Windsor, CO NEC: 2023
- Occupation
- Hospital Master Electrician
Only if the GFCI protection is provided by a 120/240V two-pole GFCI breaker at the supply of the MWBC.
Edit: I take that back. You could, as long as on the load side of the GFCI's, you have seperate neutrals (no MWBC). So, the home run goes to a GFCI, two-wire load side out, and two-wire line side out to the second GFCI would work. If you mixed the different load sides up, they'd trip.
Edit: I take that back. You could, as long as on the load side of the GFCI's, you have seperate neutrals (no MWBC). So, the home run goes to a GFCI, two-wire load side out, and two-wire line side out to the second GFCI would work. If you mixed the different load sides up, they'd trip.
Last edited:
Filthy Phil
Member
I was thinking MWBC to a JB, then one leg and pigtailed neut to the line side of a GFCI, and the other leg and a pigtailed neut to the line side of another GFCI. Each of the GFCI's would have downstream rec. that would be connected to the load side.
- Location
- Windsor, CO NEC: 2023
- Occupation
- Hospital Master Electrician
Agreed.
Initially, I was imagining a 3-wire homerun to the first GFI, and then 3-wire out to the second GFI, and then 3-wire out to load sided receptacles taking every other phase as you went around the room - that would not work.
Initially, I was imagining a 3-wire homerun to the first GFI, and then 3-wire out to the second GFI, and then 3-wire out to load sided receptacles taking every other phase as you went around the room - that would not work.
I assume here you're talking about GFI receps. It will work fine as long as the GFI protection begins after ('downstream') the neutral is shared.
Take your 12/3 to the first box. Pigtail the neutral between one circuit's white and the other to the line side neutral of the GFI. Connect the 12/3s red to the black of one circuit, the 12/3s black to the line side of the GFI of the other circuit.
You neutral is now split between the whites of the two circuits and will work properly and safely.
Take your 12/3 to the first box. Pigtail the neutral between one circuit's white and the other to the line side neutral of the GFI. Connect the 12/3s red to the black of one circuit, the 12/3s black to the line side of the GFI of the other circuit.
You neutral is now split between the whites of the two circuits and will work properly and safely.
weressl
Esteemed Member
They should work fine.Filthy Phil said:
The only problem I have experienced with long circuits and multiple outlets on the same GFCB that in high humidity the capacitive coupling of the wiring became so high that we would experience nuissance trips.
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