What a GFI outlet does and why you might need to replace one

A GFI outlet (ground fault interrupter) is a safety device that cuts power when ready if it detects water or a short circuit. You'll find them in bathrooms, kitchens, garages, and anywhere near water. Unlike a regular outlet, a GFI has two buttons on its face: "Test" and "Reset."

You need to replace a GFI outlet when it stops resetting, trips constantly for no reason, or won't hold the reset button in place. A GFI that won't reset is a sign the internal mechanism has failed and the outlet can no longer protect you from electrical shock. Replacement is straightforward and takes about 15 minutes if you're comfortable working with basic tools.

Key Takeaways

  • Turn off power at the breaker panel before you touch anything inside the outlet box, and test the outlet with a voltage tester to confirm power is off.
  • Remove the old outlet by unscrewing the two terminal screws and pulling the outlet out, then disconnect the three wires (black, white, and bare copper or green).
  • Connect the new GFI outlet by attaching the black wire to the brass screw, the white wire to the silver screw, and the ground wire to the green screw, then push it back into the box and screw the cover plate on.
  • Test the new outlet with the Test button to make sure it trips, then press Reset to restore power—if it doesn't reset, turn the breaker back off and check your wire connections.

Tools and materials you'll need

Gather these items before you start: a voltage tester (non-contact or multimeter), a flathead screwdriver, a Phillips screwdriver, and a new GFI outlet rated for your circuit (usually 15 or 20 amps—check the breaker panel or the old outlet). You may also want needle-nose pliers to help bend wire ends into loops.

The voltage tester is the most important tool. It tells you whether power is actually off before you touch any wires. A non-contact tester (about $10–15) is the easiest to use: you hold it near the outlet and it beeps if power is present. A multimeter works too but requires more steps to set up correctly.

Turn off power and confirm it's safe

Go to your breaker panel and flip the breaker that controls the outlet you're replacing. If you don't know which breaker it is, turn off breakers one at a time and test the outlet with a lamp or phone charger until it stops working. Once you've found the right breaker, flip it to the "Off" position.

Return to the outlet and use your voltage tester to confirm power is off. Touch the tester to both the top and bottom slots of the outlet. If the tester beeps or lights up, power is still on—go back to the panel and try a different breaker. Once the tester shows no power, you're safe to proceed.

Remove the old GFI outlet

Unscrew and remove the cover plate. You'll see two brass screws and two silver screws holding the outlet to the box. Use your flathead screwdriver to unscrew all four screws, then gently pull the outlet straight out of the box. Don't yank it—the wires are still attached.

Once the outlet is partway out, you'll see three wires connected to the back or sides: a black wire (hot), a white wire (neutral), and a bare copper or green wire (ground). Use your screwdriver to loosen the terminal screws holding each wire and pull the wires free. If the wires are bent into loops, straighten them gently with pliers. Set the old outlet aside.

Connect the new GFI outlet

Before you install the new outlet, check that the wire ends are clean and not frayed. If they are, strip about 1/2 inch of insulation from each wire using a wire stripper or your screwdriver blade. Bend each wire into a small hook shape so it wraps around the terminal screws.

Attach the black wire to the brass screw on the right side of the outlet. Wrap the wire clockwise around the screw and tighten it snugly—not so tight that you crush the wire, but tight enough that it doesn't move when you tug it. Attach the white wire to the silver screw on the right side the same way. Attach the ground wire (bare copper or green) to the green screw, usually at the bottom of the outlet.

Double-check that no bare wire is visible outside the terminal screws and that each wire is connected to the correct screw. Gently push the outlet back into the box, making sure the wires fold neatly behind it and don't get pinched. Screw the outlet to the box with the four screws, then attach the cover plate.

Test the new outlet and restore power

Go back to the breaker panel and flip the breaker back to "On." Return to the outlet and press the "Test" button. You should hear a click and the outlet should stop working (a lamp plugged in should turn off). This means the GFI is working correctly.

Press the "Reset" button to restore power. The outlet should click again and power should return. If the outlet doesn't trip when you press Test, or if it won't reset, turn the breaker off again and check that all three wires are connected to the correct screws. Loose or reversed wires are the most common reason a new outlet doesn't work. If everything looks correct and it still doesn't work, the new outlet may be defective—swap it for another one.

When to call a licensed electrician

If the outlet trips repeatedly even after you've replaced it, there may be a short circuit or water damage in the wall. Stop using the outlet and call an electrician. If you're uncomfortable working with electricity at any point, or if the outlet box is damaged or the wires are corroded, call an electrician rather than proceeding. Electrical work done incorrectly can cause fires or shock hazards.

If you live in a jurisdiction that requires a permit for outlet replacement, you may need a licensed electrician to do the work or to inspect it afterward. Check with your local building department before you start.

Frequently Asked Questions

Can I replace a GFI outlet with a regular outlet?

No. GFI outlets are required by code in bathrooms, kitchens, garages, and outdoor areas because they protect against electrical shock near water. Replacing one with a regular outlet removes that protection and violates building code. Install a new GFI outlet instead.

What if the outlet box is too crowded and I can't fit the new outlet?

GFI outlets are slightly larger than regular outlets. If the box is too tight, you may need to remove excess wire insulation or carefully fold the wires. If there's truly no room, you may need a shallower outlet box or a professional electrician to relocate the box.

Do I need to turn off the whole house?

No. Turn off only the breaker that controls that outlet. Turning off the whole house is unnecessary and will cut power to everything. Use a voltage tester to confirm the specific outlet is off before you touch it.

Why does my new GFI outlet keep tripping?

A new outlet that trips constantly usually means there's a short circuit or water in the wall, not a problem with the outlet itself. Stop using it and call an electrician to find the source. Do not keep resetting it, as this can damage wiring or create a fire hazard.

Can I use a GFI outlet in a wet location like a shower?

GFI outlets are not waterproof and should not be installed where they will be splashed directly or submerged. In wet locations, use a standard outlet with a GFI-protected cover plate, or install the outlet outside the wet zone and use a GFI circuit breaker at the panel instead.