I am having a problem switching a switch/outlet combo to a GFCI/switch combo. The GFCI switch provides power to a bathroom fan and light that are not protected.

I have wired the GFCI/switch as shown in the photo and when I test the GFCI using the test/reset buttons, the GFCI works properly. When I test the outlet with Gardner Bender tester, I receive a "correct" indicator. However, when I press the Gardner Bender test button, I receive "hot/enter image description herenew rev" indication and the GFCI outlet does not trip. Suggestions?

  • What is the model of the GFCI unit I haven't seen one quite like that , are the 2 back connections back stabs or hard wired for the switch. With the switch wired to the line side if that is the switch the device on the switched leg is not protected. Move the switch connection to the load side and it will probably work.
    – Ed Beal
    Commented Aug 17, 2017 at 17:10
  • The model is GFSW1-KW. The wires for the switch are hard wired into the device. The box only has one wire (blue) going to the light.
    – Mike M.
    Commented Aug 17, 2017 at 19:09
  • How certain are you that your incoming green wire really is grounded? The GFCI's test would work even if it wasn't...
    – brhans
    Commented Aug 17, 2017 at 19:49
  • Ok so it is the GFCI outlet that is not tripping when you press the test on the GB tester.
    – Ed Beal
    Commented Aug 17, 2017 at 21:24
  • 3-light GFCI testers will not work if the ground is not good. They steal ground to induce a ground fault. No device can cause a ground fault if it's only attached to hot and neutral. The steel conduit is a valid grounding path, so look for broken conduit or a noncontinuous path for grounding wires, however that is done. Do not count on the screws grounding the yoke of the receptacle to the steel box. Commented Aug 17, 2017 at 22:56

1 Answer 1


My suspicion: an open ground

This is based on two factors:

  1. Your three-lamp tester is unable to trip the GFCI, but the GFCI tests OK. This is because the internal TEST button doesn't rely on the ground (it goes load-hot to line-neutral or vice versa), but the three-lamp tester's TEST button is connected hot-to-ground, and thus requires a solid ground connection to work.

  2. Pushing the TEST button on your tester yields a "hot/neutral reverse" indication despite it testing correctly initially -- the "correct" indication is due to capacitive coupling between neutral and ground providing a current path "home" for the current through the right-hand lamp.

I'd check to make sure the green wire is securely connected to the box in your case; if it is, then the problem's upstream somewhere as it appears this receptacle was wired using conduit (note the locknut and fitting at the bottom of the box). If you can't find it still -- call in an electrician, as they should have better tools (such as an earth fault analyzer/loop impedance tester) that can be applied to the problem.

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