I have a two-gang box where the first device is a GFCI and the other is a switch/outlet combo. (switch on top controls a fixture elsewhere, and a standard outlet at bottom which should be always on.)

There are two pairs of wires coming into the box. Can anyone point me toward a diagram of the correct wiring in this situation?

  • Not enough info about the wires coming in: Is one wire the source, and the other wire running to the switch? Does the switch have its own power source? Or is it just two wires (plus ground of course) from this location that go to the switch? Depending how the wires run you'll either have to break one, or possibly both, tabs on the outlet.
    – Tyson
    Apr 18, 2017 at 12:54
  • Presumably one pair of wires is the source and the other runs to the light that the switch controls, so it does not have independent power. I believe this setup worked previously, and the tabs on the switched outlet are not broken.
    – nvioli
    Apr 18, 2017 at 13:15
  • I see now: I missed that the second device is a switch / outlet combo device and that the switch is for a light elsewhere. Is that correct?
    – Tyson
    Apr 18, 2017 at 13:18
  • Yes, that's correct.
    – nvioli
    Apr 18, 2017 at 13:19
  • Do you want the other outlet to also be protected by the GFCI? How about the light? - I recommend protecting all the outlets, but not the light, so when the GFCI trips you won't be in the dark. Apr 18, 2017 at 20:49

1 Answer 1


First you must determine which of the two cables entering the box is the power source, and which goes to the light fixture. The one with the single wire that goes to the dual device without any wire nuts is probably the cable to the light fixture, but the way to tell for sure is to disconnect the hot (black) wires of both cables and test them with a volt meter.

If you want the GFCI to protect all the outlets, but leave the light on if it trips, wire it like this:

GFCI + dual device outlet and light switch

Break and remove the tab between the two hot terminal screws on the dual device.

Use a wire nut and a white jumper to connect the white wire from the power source to the white wire to the light fixture, and to the silver LINE screw on the GFCI.

Use a wire nut and a black jumper to connect the black wire from the power source to the brass LINE screw on the GFCI, and to one of the switch screws on the dual device.

Connect the other switch screw on the dual device to the black wire to the light fixture.

Use a white jumper to connect the silver LOAD screw on the GFCI to the silver outlet screw on the dual device.

Use a black jumper to connect the brass LOAD screw on the GFCI to the brass outlet screw on the dual device.

If your GFCI outlet doesn't have LINE and LOAD terminals, or if your dual device doesn't have four screw terminals, then you have unusual equipment and this diagram won't make sense. In that case, modify your question to describe your devices.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.