Last Updated on May 17, 2023 by Dave Farquhar
A GFCI outlet without ground wire isn’t ideal, but it’s better than a 2-prong outlet. A GFCI outlet will work without a ground wire and it’s legal. Here’s how to properly wire a GFCI outlet without the ground wire, and label it to meet code. If the outlet shorts out for any reason, it will still trip for safety, even without ground.
A GFCI without ground wire won’t protect electronic equipment from static electricity, so you have to label it as such, but it will protect human life in the event of a short circuit. And, if your goal is to pass an inspection, an electrical tester will cause it to trip. Installing a GFCI is an acceptable alternative to the dangerous and illegal practice of a bootleg ground.
Safety first
Safety first: Turn off the power at the breaker box. It’s not safe to work on an outlet with the power on. Plug a light or better yet, a television or radio into the outlet, turn the power on, then flip breakers until the light or sound stops. If you use a light, you may need a helper. This is why I like to use something that makes sound, like a radio, since I may or may not have someone around to help.
Wiring a GFCI outlet without ground wire
A GFCI outlet has two sets of terminals, one for the incoming line coming in, and one for the load, for chaining outlets. The load terminals will be covered with a piece of tape. On regular outlets all of them are interchangeable, but not on a GFCI. Read my line vs load blog post for more details if this wiring concept is unclear.
If you have two wires, wire the black wire to the brass terminal. Wire the white wire to the silver one. Remember, black to gold, white to white. Leave the ground terminal on the GFCI unconnected. Reversing polarity is a code violation, so wire it properly.
If you have four sets of wires and don’t know which ones are hot, you’ll have to disconnect the outlet and separate the wires. Turn the power back on, then carefully use a multimeter to find the live wires. Connect one black wire to one white wire. If it measures 0 volts, try another combination until you find one that measures about 115 volts. Turn the breaker off, note the wires, then hook that wire pair up to the incoming pair of terminals. Connect the other pair, the load, to the load terminals.
Replace the cover plate, then turn the power back on at the breaker box.
Do GFCI outlets work without ground?
A GFCI outlet still performs its intended function without ground. If electrical current takes something other than its normal path, the GFCI will shut down. It doesn’t need ground to function in that way.
The misconception with GFCI is that it can provide ground to protect equipment when no ground wire is hooked up. That is incorrect. You can think of it this way: A GFCI outlet without ground works to protect you, but can’t do anything to protect a computer you plug into it.
Labeling a GFCI without ground wire
GFCI outlets come with a sticker that reads NO EQUIPMENT GROUND. After replacing the cover plate, stick one of those stickers on the plate. That way anyone who uses the outlet in the future can know the outlet lacks a proper ground but is still a GFCI outlet with safety features. GFCI outlets function properly without ground, in the sense that they can still shut down to protect a human being from accidental electric shock. What GFCI outlets can’t do without a ground prong is protect any equipment plugged into them.
David Farquhar is a computer security professional, entrepreneur, and author. He started his career as a part-time computer technician in 1994, worked his way up to system administrator by 1997, and has specialized in vulnerability management since 2013. He invests in real estate on the side and his hobbies include O gauge trains, baseball cards, and retro computers and video games. A University of Missouri graduate, he holds CISSP and Security+ certifications. He lives in St. Louis with his family.