How to Wire an Outlet and Add an Electrical Outlet Yourself

Find Your Power Source

• Determine where you’ll get power for your new receptacle.
• Look on the wall behind your new location and determine if the circuit can handle another receptacle.
• Call a licensed electrician or your local code authority for help if needed.

Turn Off the Power

• If known, locate the breaker for the old receptacle that will feed your new receptacle and turn it off.
• Test your non-contact voltage tester on a known live circuit to verify it works.
• Insert the tester into the old receptacle’s narrow slot. If you hear a beep, stop and try another breaker.
  • Repeat turning off breakers and testing for power until you find the right one.
• Remove the face plate and carefully pull out the receptacle.
• Use the tester to ensure all wires in the box are dead before moving on.

Reference Location of Existing Receptacle

• Using a stud finder, locate the stud to which your old receptacle is attached. Mark it with painter’s tape.
• Measure 16 inches to the next stud, and mark it with painter’s tape. If you don’t find a stud at 16 inches, try 24 inches.
  • Ensure the receptacle is between the two studs in the marked wall cavity.
• Determine a reference point that you can find on the other side of the wall and measure the distance to the receptacle.
  • Measure from a shared wall, a pipe that extends through both sides or another common reference point.

Lay Out New Receptacle

• Measure from your common reference point on the other side of the wall. Mark the location of the old receptacle and studs.
• Pick a spot for your new receptacle, keeping it within the same wall cavity but not right behind the old device.
  • You don’t want the receptacles exactly back-to-back. It’s a tight space, and you need room for both boxes and cables.
• Mark the wall at your desired height, ensuring you’re not on or within two inches of a stud.
  • Note whether your mark will be the bottom, top or center of the new receptacle, especially if you’re matching existing ones.
• Hold the cut-in box level on your mark, open the side facing the wall, and trace around the outline.

Cut In New Box

• Use a drywall saw to cut just inside the outline of the box you drew on the wall.
• Cut horizontally first, in case you encounter an obstruction. Move the box outline sideways, away from the obstruction, if needed.
• Avoid making the hole too big. You want a tight fit, and you can always make the hole bigger, never smaller.
• Test fit the cut-in box, then remove.

Prep the Existing Receptacle

• Double-check that the power is off and pull out the old receptacle.
• Cut a length of non-metallic sheathed cable, aka NM-B or Romex, long enough to reach between the two receptacles with a foot extra on each end.
• Open the cable clamp at the back of the plastic box and push one end of the NM-B through the opening.
  • If you have a metal box, knock out an access hole and use an appropriate cable connector.
• Strip the exterior covering from the NM-B so that at least a quarter-inch of sheathing remains in the box.
• Cut the NM-B so you have about 6 to 8 inches to work within the box, and strip the insulation back about three-quarters of an inch.

Wire the Existing Receptacle

• Splice every bare copper or green wire present in the box to the bare pigtail, and attach the pigtail to the receptacle’s green screw.
• Look at the existing cable(s) in the box:
  • If you have one hot and one neutral attached directly to the receptacle, attach the new white neutral to the free silver terminal screw and the new black hot to the free brass screw. (This will save room, but you can also use pigtails.)
  • If you have hots bundled together under a wire nut and neutrals bundled under a separate wire nut, with pigtails attached to the receptacle, undo the wire nuts and add your new wires to the appropriate bundle.
• Make good connections by making hooks in the ends of the wires, wrapping them clockwise around the screws, and tightening them with a screwdriver. Do not use the back-stab holes in the receptacle, as they tend to loosen over time.
• Tug on every connection to ensure all wires are tight and can’t come out of their splices.
• Wrap electrical tape around the receptacle terminals and reassemble the receptacle and cover plate.

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Prep Cable and Secure Cut-In Box

• Reach into the hole on the other side of the wall and pull out the NM-B cable.
• Push the cable through one of the openings in the box, leaving enough to have some slack inside the wall.
• Cut the cable so you have at least three inches sticking out of the front of the box.
• Push the box into the hole and tighten the ears against the drywall, leveling the box as you go.
• Strip the sheathing, leaving at least a quarter-inch inside the box.
• Strip about 3/4-inch of insulation off the white and black wires.

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Wire The New Receptacle

• Attach the bare copper wire to the green screw on the receptacle.
• Attach the white wire to the silver screw and the black wire to the brass.
• Tighten all connections with a screwdriver and tug to ensure they are secure.
• Wrap electrical tape around the receptacle’s terminals.
• Push the receptacle into the box. Level and secure with screws. Attach faceplate.
• Turn on the power.

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FAQ

Do I need a permit to install a new outlet?

It depends on where you live. In Dallas, where I’m from, I can install up to six 120-volt receptacles in an existing structure without getting a permit. Other places will have different rules. Contact your local electrical inspector or permitting office for details.

Can I install an outlet anywhere in my home?

No. The NEC sets rules for installing receptacle outlets, and there are many rules regarding placement and safety. Contact your local electrical inspector or permitting office for details.