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I want to install a GFCI outlet into my laundry room because this house is old and has no ground. The outlet in the laundry has 3 hot conductors and one neutral with no ground. Can I wire the 3 hot conductors together with a Wago or a nut, and then attach that to one terminal on the outlet so I can actually use the GFCI?

Follow up question - should I just get AF/GF breakers since this house is not grounded? I know that it is not a substitution for a ground, but rewiring the house is wildly expensive.

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It almost certainly has 3 neutrals. However, they are shoved into the back of the box, and a "pigtail" is brought out to the receptacle itself.

Can you do the exact same thing with the hot wires? Depends. Look closely at the side of the receptacle with the silver plated neutral screws. Do you see a small "tab" of metal connecting the two screw terminals? It's there. Got it? Now, look at the "hot" side with the 2 brass-plated screws. Do you see that same "tab"?

If you do see that tab, intact, then those 3 hots wires are simply connected to each other. You can indeed pigtail the 3 hot wires into 1 short wire and attach that to the GFCI's Line "Hot" terminal. Leave the Load terminals unused.

If you don't see the tab, that means the 2 screws are not connected and the sockets are under independent control, and may even be on different circuits. 2 of the hots will be "on the same screw" (or on a backstab connection right next the screw) and the other hot will be solo on its own screw.

The 2 hot wires that are together, must be kept together, e.g. by tying them together with a wire nut. As far as connecting to the GFCI's "Line" Hot terminal, you must do one of two things (not both):

  • Connect the solo "hot" wire (this would be my suggestion). Leave the other two "hot" wires joined together, and just push them into the back of the box. This is important so other parts of the circuit continue working.
  • cap off the solo "hot" wire (won't be used) and run a pigtail to the pair of hot wires.

If the hot wires are different colors (e.g. red and black) that probably means you have a "Multi-wire branch circuit" or MWBC, aka "shared neutral" circuit. That would certainly explain why the neutrals were pigtailed, as this is a requirement where MWBCs are concerned. Another requirement, that was probably overlooked in your panel, is having "factory approved handle-ties" between the two breakers so that a maintainer turns off half the entire MWBC when trying to service it. This "handle-tie" requirement is very important for worker safety - you must be careful to identify both breakers and turn them off, or else the circuit is still live and can bite you. If handle-ties are annoying to find, feel free to use a 2-pole 240V circuit breaker instead.

In fact, in older houses, we see so many screwball defects - far worse than untied MWBCs - that I recommend turning off the main breaker just to be sure.


You can provide GFCI protection at the breaker if you want to. But if the circuit is MWBC, you must use a 240V/2-pole GFCI breaker. Single-pole GFCI or AFCI simply won't work.

AFCI is arc fault protection - it has a digital signal processor which "listens" to the electrical "noise" on the power line, listening for - well, you know the crinkle-crunch sound when you hook up speakers with the amplifier turned on? That, basically. It's marginally useful for protecting some appliances such as electric blankets, and it's really all about protecting the wiring in the walls. If you have old wiring you don't trust, or aluminum wiring you're worried about, it's a great choice.

If your panel is GE or a Siemens predecessor (ITE, Gould, Murray) then they actually do have AFCI breakers that work on MWBCs.

Of course aluminum wiring can be easily modernized to be quite safe, as we know a great deal more about how to do it correctly.

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  • There are 2 circuits for sure. On my box there are two breakers. The old outlet was backstabbed so I assume they were all connected. There wasn’t a break in the middle to make two separate circuits on the outlet. I did get bit by the way, I used a Klein circuit finder and thought there was only one hot. Yea, won’t do that again.
    – Brian Turner
    Mar 14 at 3:58
  • Worst part is one of the three hot was white. Really poorly thought out.
    – Brian Turner
    Mar 14 at 3:59

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