I live in an old house and I am looking to replace a two prong outlet in the kitchen with a GFCI outlet . I already did this for two outlets in my garage. When I removed the outlet, I found 2 wires on each of the four poles for a total of 8 wires. I know that GFCI outlets will not work with shared neutrals. Is installing a GFCI outlet possible? I have pigtailed wires before but I'm not sure how to proceed. Thanks.

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  • 1
    Simply saying "GFCI outlets will not work with shared neutrals" is incorrect. They cannot be used with split-wired receptacles, but pig-tailing from shared neutral circuits is typically fine, depending on how the circuit is wired. Commented Jun 2, 2016 at 0:18
  • 1
    Are you sure the tabs on the existing outlet are intact? Commented Jun 2, 2016 at 0:48
  • What is the name for that prong-style of outlet? It looks like it has two "T"s. Commented Jun 4, 2016 at 2:17

1 Answer 1


Connect the feeder wires to the LINE terminals on the GFCI. The feeder wires will be one set of black and white, which bring power to box. If there are two sets of feeder wires, you'll have to install two GFCI devices. As GFCI receptacles cannot be used to replace a split receptacle (where the two receptacles are supplied by separate branch circuits).

Take all the load white wires, plus a short length (8" or so) of white wire. Using a twist-on wire connector, bundle them together. Then do the same for the load side black wires.

Connect the load side pigtails to the LOAD terminals on the GFCI device.

Finally, connect all grounding conductors together, including one to the device, and one to the metal box.

Each binding screw terminal should have no more than ONE wire connected to it. Check the manufacturer's installation instructions for the device, to determine how to properly terminate the wires.

However, with that many wires in the box, it's almost certainly over filled. So while you're doing the work, you might want to consider replacing the box with a double gang box. That would give you enough volume for the wires, and allow you to add an additional receptacle.

  • 1
    Just a quick correction, GFCI receptacle devices pretty much all use "back wired" terminals. These are terminals where the wire is stuck into a hole in the back of the device and a screw plate is tightened. Typically there are two holes at each screw and it is perfectly legal and safe to put two wires, one in each hole. ..... I know Tester means one wire per binding screw terminal, but back-wired terminal are different. Commented Jun 2, 2016 at 0:15
  • @SpeedyPetey tweeked my answer a bit. Hope it meets your approval.
    – Tester101
    Commented Jun 2, 2016 at 0:37
  • @SpeedyPetey also note, since there could be 3 LOAD wires, even two "back wired" terminal hole would require a pigtail.
    – Tester101
    Commented Jun 2, 2016 at 0:39
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    Yup, very good point in this situation, and I completely agree that that box is likely over-filled. Commented Jun 2, 2016 at 0:58
  • Thanks! It worked like a charm. I don't have the tools to cut into the tiles surrounding the outlet so I put on a shallow wall box to fit the gfci and the extra wires.
    – Tobin
    Commented Jun 2, 2016 at 22:01

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