How to Test a GFCI Outlet (and How Often)

ElectricalGuide EditorialReviewed June 20267 min readHow we research
The short answer

Testing a GFCI takes ten seconds and should be done monthly. Plug in a small load like a lamp, press the TEST button: the RESET button should pop out and the power should cut off. Press RESET and the power should come back. If pressing TEST does nothing, or power stays on, the device has failed and needs replacement. A plug-in GFCI tester gives a useful second opinion, and the quiet failure mode (an old GFCI that still passes power but no longer protects) is exactly why the monthly habit matters.

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The monthly TEST/RESET protocol

Manufacturers and safety groups recommend testing every GFCI about once a month, the same cadence as checking a smoke alarm. The procedure is simple. Plug a lamp or other small device into the GFCI and turn it on so you can see the result. Press the TEST button firmly. You should hear or feel a click, the RESET button should pop out, and the lamp should go dark, which confirms the device tripped and cut power on demand.

Now press RESET. It should click back in and the lamp should light again, confirming the device restores power normally. That full cycle (TEST cuts power, RESET restores it) is the whole test, and a healthy GFCI passes it every time. Do it on every GFCI in the home: kitchen, bathrooms, garage, outdoors, basement, and laundry.

Remember that one GFCI outlet often protects several plain outlets downstream. When you trip a GFCI with TEST, those downstream receptacles go dead too, so after testing, confirm anything important on the circuit (a refrigerator, a sump pump) is powered again before you walk away.

What should happen, and what should not

A pass looks like this: TEST cuts the power, the RESET button visibly pops out, and RESET brings the power back. If all three happen, the GFCI is doing its job. Anything else is a fail. If pressing TEST does nothing and the lamp stays lit, the GFCI is not tripping and is no longer protecting you. If RESET will not stay in or power does not return, the device or the circuit has a problem.

A GFCI that will not reset is sometimes reporting a real fault on the circuit rather than a dead device: a downstream ground fault, moisture in an outdoor box, or a miswired LINE/LOAD connection can all hold it tripped. Our GFCI troubleshooting walkthrough covers isolating that fault. But a GFCI that fails the TEST step (no trip at all) is unambiguous: it has lost its protective function and must be replaced.

One note on wiring: if the TEST button does not cause a trip but the outlet still has power, do not assume it is fine because devices work. Passing power and providing ground-fault protection are two separate things, and the next section is about exactly that trap.

The plug-in tester second opinion

An inexpensive plug-in GFCI tester is a worthwhile second check. These devices plug into the receptacle, show a pattern of lights that confirms correct wiring (hot, neutral, and ground in the right places), and include their own test button that injects a small simulated fault to trip the GFCI. If the tester's button trips the device, you have independent confirmation that the protection works, not just the button on the GFCI itself.

The tester also catches wiring errors the built-in TEST button cannot, such as a reversed hot and neutral or an open ground, which can leave a GFCI present but compromised. It is also worth knowing how GFCI and AFCI protection differ, since some circuits carry both. Its light code tells you whether the outlet is wired correctly in addition to whether it trips. For a few dollars it turns a yes/no button press into a more complete picture.

One caveat: a plug-in tester injects a fault to ground, so it relies on a real ground being present. On an older two-wire circuit with no ground, the tester's trip button may not work even though the GFCI is fine, which is a known and acceptable situation for a properly installed GFCI on an ungrounded circuit. In that case, the device's own TEST button is the valid check.

The failure mode: still powers, no longer protects

The reason to test on a schedule is a specific, silent failure: a GFCI can keep delivering power to everything plugged into it while its ground-fault sensing has worn out, so it no longer trips on a real fault. Nothing looks wrong, the outlets work, and the protection is simply gone. You only discover it by pressing TEST and finding nothing happens.

This is most common on older devices. GFCIs have a finite service life, and units roughly ten years or older are the prime suspects for this failure. Years of heat, surges, and humidity degrade the internal electronics that detect leakage. The simple rule: a GFCI that fails its monthly TEST gets replaced, and an old GFCI is worth proactively replacing even if it still happens to pass.

If a GFCI fails the test, will not reset on a circuit you cannot diagnose, or is wired without a ground and you are unsure whether it is set up correctly, a licensed electrician can replace the device and verify the LINE/LOAD wiring. A GFCI outlet replacement is inexpensive, so treat a failed GFCI as a safety item, not a someday item.

Testing breaker-type GFCIs and logging it

GFCI breakers are tested the same way, just at the panel, and the choice between a GFCI breaker and a GFCI outlet changes where you do the test. Open the panel cover door and find the breaker, which has its own small TEST button on its face. Press it; the breaker should trip to the middle (off) position, confirming it sensed the simulated fault. To restore it, push the handle fully to OFF and then back to ON, which is how a tripped breaker is reset. If the TEST button does not trip it, the breaker has failed.

As with outlets, tripping a GFCI breaker kills the whole circuit it protects, so make sure nothing critical is mid-task and restore power afterward. If you are not comfortable opening the panel door, that is a reasonable place to ask for help rather than poke around live.

Finally, treat GFCI testing like smoke-detector testing: do it monthly and write it down. A small log (a note on the panel door, a phone reminder, a sticker by the receptacle) turns an easy-to-forget chore into a habit and gives you a record of when each device last passed. The ten-second test is only protective if it actually happens, month after month.

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Common questions
How do I test a GFCI outlet?
Plug in a lamp and turn it on, then press the TEST button. The RESET button should pop out and the power should cut off. Press RESET and the power should return. That full cycle (TEST cuts power, RESET restores it) means the GFCI is working. If TEST does nothing or power stays on, the device has failed and needs replacement. Test every GFCI in the home about once a month.
How often should I test a GFCI?
About once a month, the same cadence as checking a smoke alarm. GFCIs can fail silently while still passing power, so a monthly TEST is the only reliable way to confirm the protection still works. Logging each test, like a smoke-detector log, helps turn it into a habit and records when each device last passed.
Why won't my GFCI reset?
A GFCI that will not reset is often reporting a real fault rather than a dead device: a downstream ground fault, moisture in an outdoor box, or miswired LINE/LOAD terminals can hold it tripped. Unplug everything on the circuit and try resetting; if it holds, plug devices back one at a time. If it still will not reset, a licensed electrician can find the fault or replace the device.
Do I need a plug-in GFCI tester?
It is a useful second opinion. A plug-in tester confirms correct wiring with a light code and injects a small simulated fault to trip the GFCI independently of its own button, catching errors like reversed wires or an open ground. Note that on an older ungrounded circuit the tester's trip button may not work even when the GFCI is fine, so use the device's own TEST button there.
How do I know if a GFCI has gone bad?
It fails the TEST step: pressing TEST no longer cuts the power. The dangerous failure mode is a GFCI that still passes power to everything plugged in but no longer trips on a real fault, so nothing looks wrong. This is most common on devices roughly ten years or older. Any GFCI that fails its monthly test should be replaced, and an old one is worth replacing proactively.
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