How to replace a GFCI receptacle

This article originally developed for EHD, Inc. by Mark Lamendola

Any contractor or homeowner who is removing and reinstalling a GFCI, but does not have formal electrical training. This guide assumes the original installer installed the GFCI correctly.

A Ground Fault Circuit Interrupter will shut a circuit off when neutral leakage current exceeds a preset value—normally 6 mA. For it to do this, it must have the proper neutral connections. These devices, if wired properly, are very good; however, never assume any such device will protect you if you choose to work the circuit hot.

A step by step guide to removal

1. Test the GFCI first. Test the GFCI by pushing the TEST button. It should click and shut off the GFCI. Push the RESET button to reset the GFCI. If it’s defective, let the homeowner know (contractor), otherwise you will replace it for free later on.
2. Shut off the breaker that feeds the GFCI. Use tape or a breaker lockout device to indicate this breaker must stay off.
3. Test the GFCI to see if it is hot. Test a known hot circuit to make sure your tester works, then check the GFCI again.
4. Remove the cover, taking care not to tear the gasket.
5. Remove the GFCI itself, and pull it toward you. Rotate the face until you can read the markings on the back of the breaker. You may need to disconnect the ground wire to do so.
6. Note which of the white wires connects to the LOAD side and which connects to the LINE side. You must not interchange these, or the breaker will not work properly. Mark the line side in some manner. Wrap a strip of tape around it, write on it, put a dab nail polish on it, whatever., Do not simply twist it to one side, stick a connector on it, or say, "The longer wire is it." Wires move when you work—make sure you mark the wire. Always mark the LOAD side—this way, you can remember that the marked wire is the LOAD wire.
7. Remove whatever you need to remove to do your work. Put all the parts in a box or a bag, and set this in a safe place where you won’t kick it or knock it over.

A step by step guide to reinstallation

General notes: Make all wire connections tight. When wrapping wires around termination screws, make sure the curve of the wire follows the tightening direction of the screw. You want the tightening action to work WITH the bend of the wire, not against it—if this is unclear to you, then watch the wires’ action as you tighten and this will become clear to you.. Make sure none of the wire’s insulation is under the screw.

1. When you are ready to install again, make sure you have enough clearance for the original box and cover. If you do not, then make clearance. If you do not use the original materials, you violate the UL listing and are open to a lawsuit (contractor) or insurance denial of payment (homeowner). If the gasket is shot, buy a new cover/gasket set. Such a set is cheaper than even one minute of an attorney’s time.
2. Seal any holes in the box, regardless of whether they were sealed originally. Pay attention to where the wires come in. Any silicone-based caulking will work. Do a neat job—no need to slop caulking all over the inside of the box. If you don’t get a perfect seal, don’t worry.
3. Connect the ground wire.
4. Connect the LINE side neutral wire. If you do not know which side is LINE, you need to test for that. To do so, tape the end one of the white wires. Connect a meter between the other white wire and the black one. Turn the panel circuit breaker on. If your meter works, you have the correct wire. If not, then repeat the test, using the other white wire. Tape or lock out the panel breaker once you finish testing.
5. Connect the LOAD side neutral wire and the black wire.
6. Carefully fold the wires back into the box, and push the GFCI into place. Secure the GFCI with its original screws.
7. Turn the panel breaker back on.
8. Test the GFCI by pushing the TEST button. It should click and shut off the GFCI. Push the RESET button to reset the GFCI.
9. Install the cover, taking care to put the gasket in so it doesn’t get folded or kinked.
10. Test the GFCI again.

Mark Lamendola is an electrical engineer, master electrician, and technical editor for an electrical trade magazine. He is a Senior Member of the Institute of Electrical and Electronic Engineers and is a frequent speaker at industry functions. He is also an MBA and Certified Manager; he is familiar with legal implications of taking unsafe shortcuts and cost-justifying doing a job safely.

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