How to Add an Electrical Outlet

Closeup showing adding an outlet to an existing wall

The Spruce / Kevin Norris

Project Overview
  • Working Time: 2 - 3 hrs
  • Total Time: 2 - 3 hrs
  • Yield: One new receptacle
  • Skill Level: Intermediate
  • Estimated Cost: $10 to $20

It is very common for older homes to be lacking enough electrical outlets. Modern codes require that that all points along a wall in a standard room should be no more than 6 feet from an electrical outlet, but in homes built before 1950, it's not uncommon to find rooms with only a single outlet. The best solution to this situation is to add a cable run to extend a circuit from one of the existing outlets to a new outlet location. This is one of the most common service calls performed by professional electricians, but it is entirely possible for a homeowner to do this as a DIY project. It does, however, take some experience and knowledge of how an electrical circuit works.

Before You Begin

There are many ways to do to this project, but the method described here allows you to extend a circuit from an existing outlet to a new outlet location without damaging the wall in a way that requires time-consuming repair. By removing the baseboard molding and removing a small strip of drywall near the bottom of the wall, you can drill holes through studs near the floor to run electrical cable. When completed, replacing the baseboard will cover all signs of your work.

Before starting, identify the circuit that controls the existing outlet that will serve as the power source for the new outlet. This circuit will need to be turned off at the main service panel in order to make your final electrical connections. Also pay attention to the amperage rating of the circuit, as this will dictate the wire-gauge of the cable use. A 15-amp circuit will call for 14-gauge wire; a 20-amp circuit calls for 12-gauge wire.

Safety Considerations

Part of this project will require you to connect wires to an electrical circuit, which always comes with inherent dangers. It is critical that you know how to turn off circuits at the main service panel and how to test for power. If you are unclear on either of these skills, this is not a project you should attempt.

While extending a circuit to add an outlet is a relatively minor project, in most communities it falls under the category of "improvement" rather than simple "repair," and as such it requires a building permit and inspection. Always check with your building inspection office to learn about permit requirements. Ignoring local requirements for permitting and inspection is never a good idea.

When to Call a Professional

In homes that have up-to-date wiring made with code-compliant non-metallic (NM) sheathed cable, this is a relatively simple project. But in older homes that haven't been updated, the wiring system can look much different, and it may be lacking the essential grounding wires that are necessary for safe installation. If you find this to be the case, it's best not to attempt this work yourself. Instead, call a professional electrician, who may need to perform additional work to bring the system up to current code.

It's also a good idea to call a professional whenever you encounter unexpected situations or when you become confused about the right way to proceed.

What You'll Need

Equipment / Tools

  • Non-contact circuit tester
  • Screwdriver
  • Pencil
  • Utility knife
  • Putty knife
  • Drywall saw
  • Level
  • Drill
  • 3/4-inch spade or auger bit
  • Fish tape
  • Cable ripper
  • Wire stripper
  • Needle nose pliers
  • Hammer


  • Old work electrical box
  • NM cable (14-gauge for 15-amp circuit, 12-gauge for 20-amp circuit)
  • Wire connectors
  • Drywall screws
  • Finish nails


Tools needed for adding an electrical outlet to an existing wall

The Spruce / Kevin Norris

  1. Turn Off the Power

    At the main service panel, shut off the power controlling the circuit that serves the electrical outlet from which you'll be feeding cable for the new outlet.

    Use a non-contact circuit tester to verify that power is off at the outlet.

    Checking that the power to the outlet is off

    The Spruce / Kevin Norris

  2. Extract the Existing Outlet Receptacle

    At the existing outlet that will feed the circuit extension, remove the cover plate, then loosen the mounting screws and extract the receptacle from the box. Try to leave the wire connections intact, but gently pull the receptacle to one side so you have access to the inside of the box.

    Examine the receptacle and its wire connections. Ideally, the feed wires should connect to silver and brass-colored screw terminals on opposite sides of the receptacle, leaving an open pair of screw terminals. These open screw terminals will accept the wires from the new cable that will feed your new outlet.

    If the wiring configuration seems more complicated than this, it's a sign that you may want to hire an electrician to complete the work.

    Also examine the electrical box. It should have several openings through which a new cable can secured. The method for securing cables will vary depending on the type of box, In some cases, it may require an additional metal cable clamp, but other boxes have built-in clamps.

    Examining the existing outlet and its wiring connections

    The Spruce / Kevin Norris

  3. Remove the Baseboard Trim

    Draw a fine pencil line along the wall at the top of the baseboard, from the existing outlet to the new outlet location. This line will serve as a reference for the following steps.

    Use a utility knife to slice through any paint sealing the joint between the baseboard and wall. Use a putty knife and small flat pry bar to carefully pry the baseboard away from the wall. Be careful, as old baseboards can be brittle and prone to cracking.

    Remove the nails from the baseboard and set it aside.

    Using a crowbar to pull back molding from the wall

    The Spruce / Kevin Norris

  4. Remove the Drywall

    Using a drywall saw, cut away a long strip of drywall just below the pencil mark. Be careful not to cut too deep, as you could cut a wire hidden behind the drywall. Carefully pull the strip of cut drywall away from the wall. Set it aside so that you can reinstall it later.

    Using a saw to cut away the drywall

    The Spruce / Kevin Norris

  5. Cut a Hole for the New Outlet Box

    Mark the desired location for the new outlet box on the wall. It should be at the same height as the existing outlets in the room—normally about 12 inches from the floor to the bottom of the box. You will be using an "old work" retrofit electrical box, so the new outlet is best positioned midway between wall studs. Position the box against the wall, using a level to ensure it is level, then draw a pencil outline around the box on the wall.

    Use a drywall saw to cut out the drywall along the marked outline.

    Marking where to cut a hole for the new outlet box

    The Spruce / Kevin Norris

  6. Drill the Studs

    Using a drill and a 3/4-inch spade bit or auger bit, drill holes through the centers of the studs, just above the floor plate.

    Cutting the hole for the new outlet

    The Spruce / Kevin Norris

  7. Run the Cable

    Measure and cut a length of NM cable to run from the existing outlet to the new outlet, through the holes drilled in the studs. Allow about 1 foot of excess cable at both wall boxes. (A 15-amp circuit calls for 14-gauge wire; 20-amp circuits use 12-gauge wire.)

    Beginning at the new outlet location, run cable down through the wall opening, then through each drilled hole in the stud, up to the wall cavity where the existing outlet is located.

    Running the cable through the wall stud

    The Spruce / Kevin Norris

  8. Feed Cable into the Existing Box

    Feeding the new cable into the existing box is one of the trickier parts of this project.

    One of the easiest ways is to extend a fish tape down through a knockout opening in the electrical box down through the wall cavity to a point where you can secure it to the new cable with electrical tape. Then, pull up the fish tape, drawing the cable through the knockout opening and into the electrical box. Pull 8 to 12 inches of cable into the box, then secure it in place using the internal cable clamp or locknut.

    Running the cable and wires through the electrical box

    The Spruce / Kevin Norris

  9. Install the New Box

    With cable secured at the existing outlet location, return to the cutout opening for the new outlet, and thread the cable into the new old-work electrical box. Make sure you have at least 8 inches of excess wire extending into the box. Secure the cable to the box with the internal cable clamp.

    Insert the box into the cutout opening, and secure the box in place with the retention tabs attached to the box, or with Madison straps.

    Installing the new box in the wall cutout

    The Spruce / Kevin Norris

  10. Connect the New Outlet

    • Use a cable ripper to cut into the outer jacket of the cable, beginning about 1/2 inch past where it enters the box.
    • Use a utility knife to carefully cut away the loose jacket.
    • If necessary, trim off the black hot wire, the white neutral wire, and the bare copper grounding wire to a total length of about 8 inches.
    • Strip 3/4 inch of vinyl insulation off the tip of the black and white wires.
    • Use needle-nose pliers to form a small C-shaped loop in each wire, then attach the black wire to one of the darker, brass-colored screw terminals on the side of the receptacle.
    • In the same manner, connect the white wire to a silver (neutral) screw terminal on the opposite side of the receptacle. Connect the bare copper grounding wire to the green grounding screw on the strap of the receptacle.
    • Tuck the wires into the box and attach the receptacle to the box with its mounting screws.
    • Install the cover plate and you're finished with this outlet.
    Connecting the new outlet

    The Spruce / Kevin Norris

  11. Connect the Existing Outlet

    If you see that there there is an empty brass hot screw terminal and an empty silver neutral terminal on the existing receptacle, then the new cable can be stripped and its wires attached to these screw terminals (white wire to silver terminal, black wire to brass terminal). The bare copper grounding wire, however, will need to be joined the existing grounding wires by detaching the grounding wire from the receptacle and adding a short bare copper pigtail wire. All the grounding wires entering the box, as well as the receptacle's pigtail, are joined together with a wire connector.

    But if all screw terminals on the receptacle are being used, then you will need to detach all wires and use short pigtail wires and wire connectors. This involves cutting scrap pieces of black, white, and bare copper wire, then using wire connectors to join the receptacle and the new cable extension to the corresponding existing circuit wires.

    When the wire connections are complete, gently fold the wires into the box, attach the outlet to the box with its mounting screw, then reattach the cover plate.


    Connecting the new cable run to the existing outlet can be one of the trickier parts of the job, as wiring configurations can vary considerably depending on where the outlet falls along the circuit layout. This is the point where a good working understanding of electrical circuits is helpful. If this part of the job becomes confusing to you, then it's a sign you should call in an electrician to finish the final hook-up.

    Connecting the existing outlet

    The Spruce / Kevin Norris

  12. Turn on Power and Test

    The final step is to turn the circuit back on and test the circuit. Be sure to test both the new and the existing outlet, using a circuit tester.

    Testing the new outlet

    The Spruce / Kevin Norris

  13. Install Drywall and Trim

    Using drywall screws, reinstall the drywall piece that you earlier cut out. Take care not to drive screws into the cable running through the studs.

    Reinstall the baseboard molding, using finish nails.

    Connecting the existing outlet and reinstating the cut drywall

    The Spruce / Kevin Norris