Ground an Outlet
Older homes often have two-pronged outlets that need to be replaced with a Ground Fault Circuit Interrupter (GFI or GFCI) receptacle. Some newer houses may likewise have an outlet that was not grounded properly or the ground wire may have become loose or disconnected. Doing this yourself can help save you from hiring an expensive electrician, and it's a relatively simple procedure with the right preparation and know-how.
Contents
Steps
Getting Started
- Purchase a circuit tester at a local home repair store. A circuit tester plugs into the outlet and has several light sequences to indicate the different problems an outlet may have. If you're going to ground an outlet, it's an important tool to have. You can purchase these at any home repair store. One model has a button to test GFCI outlets. It's a little more money but a better buy to verify the GFCI.
- Test the outlets of your home. Plug the circuit tester into each outlet and look at the indicator lights. If the lights indicate the outlet is not grounded properly, mark the cover with a piece of masking tape. Move on to the next outlet.
- Do not try to fix more than one outlet at a time. Unless you are sure of your work, its better to check them one at a time. This may involve turning the electrical circuit breaker on and off many times while you work.
- Turn off the power at the main electrical box. Either turn off the circuit breaker that controls the outlets to the specific room or turn off the main switch for the whole house. If you only turn off the breaker, retest the outlet with the circuit tester to ensure it's the correct one.
- Remove the cover plate of the outlet. For the most part, cover plates will be attached with flathead screws, which means you should be able to easily remove them with a small, flathead screwdriver. If paint or wallpaper is in the way slightly, you might need to carefully cut around the outlet with a utility knife to keep the wallpaper from tearing and making the wall look raggedy.
- Check your local wiring codes and schedule inspections. Several inspections and permits are required for most residential construction projects, especially when it involves electrical work. To make sure you're up to code, you may need to schedule temporary service inspection, a rough-in inspection, and a final inspection. This needs to be done whether you're doing it yourself or hiring a subcontractor.
- The National Electrical Code requires all GFCIs within 5 feet of the floor to be child-safe and clearly marked. Outdoor GFCIs must also be weather resistant and clearly marked, even if it has a weather cover.
- Check your local wiring codes to see if a GFCI is an acceptable replacement for a non-grounded two-prong outlet. There are acceptable installation procedures for non-grounded GFCI usually involving putting a sticker on the outlet cover stating "Non-Appliance Ground." In some areas, you may need a GFCI due to nearby water fixtures.
Examining the Outlet
- Remove the outlet. Unscrew the mounting screws located at the top and bottom of the outlet. You may need to cut the painted edge and pry it loose. Pull out the outlet from the box as far as the wires allow and locate the green grounding screw near the bottom of the receptacle.
- Locate the grounding wire, if applicable. The grounding wire may not covered by insulation and is usually copper colored. Oftentimes, the insulation will be green.
- Examine the outlet and the wiring. If you have three wires in the box (black, white, and copper), you will need to attach or tighten the grounding wire. If you have only two wires and a 2-prong outlet, you can ground the outlet by attaching a GFI or GFCI receptacle.
- This assumes a ground wire has been run to the outlet, and that the outlet box is grounded. If your older wiring only has two wires (black and white, with no grounding wire), the box is not grounded and you will have to install a new outlet.
- In the United States, no separate ground wire may be run to an existing outlet to provide a Ground for a GFCI outlet, because it's a violation of the electrical code.
- If you have a ground wire, usually a bare copper or green wire, in the box, it may or may not be grounded, which means you should test that for ground. If you have one of those wires in the box, you can hook it up to a grounded outlet and use the tester to see if it’s properly grounded.
- Secure the ground wire. Often the grounding wire is wrapped around the cable as it enters the box and tightened beneath the clamp that secures the cable to the outlet box. In this case you can simply replace the 2-prong outlet with a 3-prong outlet, since the third prong will be grounded through the screws that mount the outlet to the box.
- Install a new outlet if necessary. If you don’t have a ground wire in the box, grounding that outlet would require installing a new outlet to code. If you are going to use a GFCI to protect and control additional outlets, you can run a wire set (3 wires) to other outlets that are in line (down the chain) from that GFCI, but only if you have a verified ground at the GFCI outlet. One GFCI will protect them, but all must have a three-prong outlet in each box. You may need to switch them all out, after ensuring you have a good ground at each outlet.
- The load screw or load terminals on the GFCI is only used if you’re trying to protect other outlets with that GFCI. There are two terminals on the outlet that are normally used: hot, neutral, ground, if necessary. Load terminal is only used in cases where GFCI is protecting other non-GFCI outlets. It wouldn’t normally be used if you’re swapping out a two-prong with GFCI.
Grounding the Outlet
- Attach the grounding wire to the grounding terminal. If the grounding wire has become loose or disconnected, loop the grounding wire over the green terminal screw and tighten with a #2 Philips screwdriver. Make a loop at the end of the copper wire with a pair of needle-nose pliers. This secures the wire onto the screw. Be sure to place the loop of the wire on the terminal screw so that when you tighten the screw, the loop is tightened and not pushed off the terminal.
- Check the connection of the other wires as well. The black wire should be securely fastened to the to the brass terminal, which is marked "load," and the white wire to the silver terminal, which is labeled "line."
- Secure the outlet. Wrap the outlet with electrical tape, covering the terminals, and push the outlet back into the box. Tighten with the mounting screws. Replace the cover plate and tighten securely, but not hard enough to crack the plastic.
- Turn the power back on. Retest with the circuit tester to be sure you now have a correctly grounded outlet. If it is a GFCI press the test button on the circuit tester to confirm its correct operation.
Warnings
- Over tightening the screw in the cover plate can cause the cover plate to crack.
- When tightening the mounting screws, be sure the outlet is straight.
- Do not over tighten the terminals when connecting the wires. If you do, and you hear something snap in the outlet, remove and discard the outlet.
Things You'll Need
- Circuit tester
- Flat head screwdriver
- 2 Philips screwdriver
- Electrical tape
- Needle-nose pliers
- GFCI receptacle (as needed). If the new GFCI didn't come with a new cover plate you may need one.
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