I'm replacing an old GFCI/Switch combo. In the old one there are two wires coming into the line side, a hot wire and a neutral. On the load side there is one wire leading up to the lighting fixture. In this configuration the outlet only works when the switch is on.

On the new GFCI/Switch combo there is a load and line side, and two black wires coming out of the back that are meant to control the switch. How do I rewire this in order to give constant power to the GFCI while controlling the light fixture with the switch using the single remaining wire?

I tried splitting the hot wire to go to both the line side and to one of the black switch wires, while connecting the other switch wire to the wire going up to the light fixture. This resulted in a large spark.

  • 3
    Large spark? You remembered to turn the power off first, didn't you?
    – BMitch
    Commented Nov 14, 2011 at 21:25

1 Answer 1


I found some helpful diagrams at do-it-yourself-help.com.

GFCI Protecting the Load

Wiring Ground Fault Circuit Interrupter Switch enter image description here

With this arrangement a receptacle, switch and disposal are protected with the ground fault breaker built into the device.

Not GFCI Protecting the Load

Wiring Ground Fault Interrupter and Light Switch enter image description here

With this arrangement the receptacle is protected but the switch remains outside the circuit. This arrangement can be used to control a light or other device where the extra protection of a gfci is not necessary.

  • An advantage of NOT putting the lights under GFCI protection would be that it doesn't go dark when something trips a GFCI outlet. This could be a safety consideration. Note however that in some situations GFCI protection for lights might be required - such as a light or light/fan combo inside a shower. That would depend on the manufacturer's requirements, AFAIK. Commented Mar 15, 2017 at 0:47

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