The GFCI in one of my bathrooms has power, but when I push the test button it does not work (does not click). The outlet in another bathroom is tied into this GFCI.

Steps taken so far:

  1. Used a digital multimeter with prong in the power and ground...got a reading of 122.4. Understood that this is an indication that there is no ground issue(?)
  2. Used a digital multimeter with prong in the neutral and ground...did not get a reading. Understood that this is an indication that the wires are not out of sequence(?)
  3. Detached the upper wires and used a digital multimeter with prong in the power and ground...got a reading of 122.4.
  4. Removed the socket and placed in another GFCI location and confirmed that here is no issue with the socket, i.e. the test switch worked as designed.

Not sure what to check next. Also, are my understandings about what the results of the tests mean accurate?

Thanks, Owen

  • What does "did not get a reading" mean? An undefined reading or a stable value close to zero? In the 1st case and assuming a TN-C-S net, there would be a serious problem, since ground and neutral needs to be connected upstream - and only upstream, never downstream - of the GFCI.
    – xeeka
    Commented May 8, 2020 at 9:24
  • Can you post photos of the inside of the box please? This smells tremendously like you are trying to stuff power into the GFCI via its LOAD terminals...newer GFCIs simply won't let you do this. Commented May 9, 2020 at 1:51

2 Answers 2


Just get a GFCI tester for $8. It allows you to quickly test outlets to see if they’re properly wired and allow you to test the GFCI itself through the test button. Inexpensive insurance for the whole house.

  • 1
    Note that these external testers require a ground connection to the outlet. Without a ground, the external tester cannot trip the GFCI but the outlet’s test button should still work.
    – DoxyLover
    Commented May 8, 2020 at 6:56
  • I used a GFCI tester and the reading I get is "correct".
    – Owen
    Commented May 22, 2020 at 22:14

It could just be that the button has failed.
Or that the black and white wires are swapped.

I would recommend getting an outlet tester that has a GFCI test button on it. It makes checking for correctly wired outlets much faster. It is also the correct way to test that the GFCI works for downstream outlets.

There should be power between the ground and the narrow side.
(If it is the wide one it is installed wrong, and the button can't work.)

If that button on the tester also doesn't trip it, you either have a failed GFCI or one that is installed wrong.

There are two sets of terminals on a typical GFCI.

One labelled LINE and the other one LOAD.

You have to make sure that the power is connected to the two terminals that are labelled with LINE.

Any other outlets that are protected by the GFCI would be connected to the terminals labelled LOAD. (There often isn't anything connected here.)

If you connect it backwards it won't matter if it is tripped or not as the power would be directly connected to the outlet. (There are some newer ones where you would have the opposite problem instead.)

Assuming you don't know which cable is which here is some directions. If you don't feel comfortable doing this, don't do it.

If it had been working until now, just replace it.
(In which case many of these steps can be skipped as you just connect the wires on the old LINE to the new LINE. )

These are the steps I would do if I couldn't otherwise figure out what was wrong.

  1. shut off the power
  2. check that it is off at the GFCI
  3. take it out and disconnect all of the wires
  4. make sure the wires aren't touching anything.
  5. keep everyone and everything away from the wires.
  6. turn on the power
  7. carefully use the multimeter to determine which cable has power
    (don't touch anything with your fingers except the multimeter)
  8. shut off the power
  9. check that it is off
  10. connect the power cable to the LINE terminals
    (black to the brass colored terminal, and white to the silver colored terminal)
  11. connect anything else that needs protection to the LOAD terminals
    (often there is nothing connected to them)
  12. install the outlet
  13. double check everything
  14. turn on the power.
  15. test that it works correctly

If it still doesn't work correctly there may be a problem with the GFCI itself. In which case you probably need to replace it.
(I have had to replace a brand new GFCI because a little plastic piece inside it broke.)

If the existing one is discolored or dirty, I would just replace it.
(I might still follow the steps above if there is any question about it being wired correctly.)

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