I need some help wiring a combination switch/GFCI outlet in the following situation. The second diagram is from the instructions and seems to match my situation, however they have an outlet downstream rather than a lightswitch (is this irrelevant?) and there are 2 black cables coming from downstream which seems to be a mistake that I need clarified.

The existing wiring is a big mess:

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Looking into the back of the box:

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An illustration of the current wiring:

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  • Hello, and welcome to Stack Exchange. Do you have the installation directions for your GFCI? Does it address this situation? Jul 15, 2016 at 21:35
  • Hi Daniel. It comes with 3 diagrams and the 3rd one seems similar to my situation, however they have another outlet downstream rather than a lightswitch, and more importantly, they seem to have made a mistake and forgot to colour-code the wires properly, as there are 2 black wires coming from downstream rather than a black and a white.
    – MarcGuay
    Jul 15, 2016 at 21:42
  • That diagram does not make sense to me. It seems to show wires labeled "black switch lead" (which would normally be a switched hot) connected to the terminal for the load-side grounded conductors (neutral). Jul 15, 2016 at 22:00
  • @JimmyFix-it -- that's where the wires for the switch come out Jul 15, 2016 at 22:09
  • The two black switch leads internally connect only to the switch, it's like a completely separate device from the GFCI.
    – Tyson
    Jul 15, 2016 at 22:25

1 Answer 1


Based on the diagram so far, here's how the GFCI switch/outlet combo should be wired:

  • Black from breaker to LINE HOT on GFCI/switch
  • White from breaker to LINE WHITE on GFCI/switch
  • White from switch-cable and white from light nutted together and pigtailed to LOAD WHITE on GFCI/switch
  • Black from switch-cable and one black from GFCI/switch nutted together and pigtailed to LOAD HOT on GFCI/switch
  • Other black from GFCI/switch nutted to black from light

(If your GFCI has the two-wire, clamp-plate terminals as in the diagram depicted, you can save a couple nuts and the pigtail wires by terminating both wires to the clamp plate instead -- they are designed to terminate two wires, one in each hole.)

  • I've modified the diagram that came with the device to match your description - does this seem correct? c2.staticflickr.com/9/8581/27734194033_a8e6c24d31_b.jpg
    – MarcGuay
    Jul 16, 2016 at 19:57
  • @MarcGuay -- yup, that's it Jul 16, 2016 at 20:09
  • Thank you. Does their colour labelling make sense to you?
    – MarcGuay
    Jul 16, 2016 at 20:21
  • And is it correct that the light/switched load will not be grounded?
    – MarcGuay
    Jul 16, 2016 at 20:36
  • @MarcGuay -- it seems like whoever drew their diagram goofed, and yes, in your case, it is correct that things aren't going to be grounded -- the GFCI protection is an acceptable substitute. Jul 16, 2016 at 21:15

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