Ground-fault circuit interrupters (GFCIs or GFIs) monitor the current entering and the current leaving them, ensuring the two currents are always equal. If there is a discrepancy, the current is escaping via another path — and a GFCI will trip the circuit. Over time, however, GFCIs can wear down and malfunction. Here’s how to check your home’s GFCIs to make sure they’re working properly.
Checking GFCIs via Their “Test” Button
All GFCIs are equipped with a “reset” button, which is usually black, and a “test” button, which is normally red. The test button provides an easy — but not comprehensive — way to check a GFCI.
To check a GFCI using its test button, you’ll need something to plug into it. Lamps work well, as they’re relatively easy to move and they’ll turn off instantly if a GFCI is tripped, but any small appliance will do. Plug any lamp or appliance you use in and turn it on to make sure it’s working properly.
If the lamp doesn’t turn on in the GFCI outlet but does at another outlet, try pressing the GFCI’s reset button — the interrupter may have been tripped. With the lamp plugged in and on, press the GFCI’s reset button. This simulates a short and should trip the GFCI.
The lamp should turn off, which indicates that the GFCI tripped and is probably working properly. You can unplug the lamp and restore power to the GFCI by pressing the reset button.
If the lamp doesn’t turn off, the GFCI is likely faulty or wired incorrectly. It’s time to contact folks with electrical expertise.
Checking GFCIs with a Circuit Tester
For a more comprehensive test, use a circuit tester that has a GFCI test button. You can buy one from your local hardware store or an online source. They’re fairly inexpensive.
To check a GFCI, plug in the circuit tester and press the test button on the circuit tester. The GFCI should trip, causing the circuit tester to lose power. This indicates that the GFCI is definitely working correctly. Restore power by pressing the reset button.
If the circuit tester doesn’t lose power, the GFCI is either worn out or there’s another issue. It’s time to contact folks with electrical expertise.
Get in the habit of checking your GFCI outlets regularly. Three times a year is a reasonable frequency for checking them. Like so many other home maintenance tasks, the task itself does not take very much time or effort. The trick is remembering to do it before something breaks and needs repair.
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