How to Run Electrical Wire Through Walls

Know how to stay safe during electrical projects and when to call a professional

Electrical wire being run through wood beam in wall for nearby electrical box

The Spruce / Kevin Norris

Project Overview
  • Working Time: 2 - 4 hrs
  • Total Time: 8 - 12 hrs
  • Yield: One cable run
  • Skill Level: Intermediate
  • Estimated Cost: $10 to $50

Any time your project involves extending or adding an electrical circuit, electricians will run new wires from the power source to the end destination. Running new electrical wires through finished walls (aka, "pulling wires") can involve pulling only a few feet of cable to an additional outlet (as demonstrated in the following steps), or pulling dozens of feet of cable to add an entirely new circuit fed by the main service panel.

Sometimes pulling wire can be the most complicated and time-consuming part of an electrical project. You first need to trace the electrical wires in your wall with a magnetic or electrical stud finder (wires will be running through drilled holes in the wall's studs.) The standard height to run electrical wire in walls is typically 16 to 18 inches above the floor and in line with the wall's outlets, so start there.

The most intricate work occurs if you are running electrical wire in a house, between floors, from a remodeled second-story space to a basement service panel. This may require removing and patching drywall in the old part of the house, which can be done by cutting a channel in the finished wall surface to assure you remove as little drywall as possible.

Before You Begin

Running electrical wires through finished walls requires a basic understanding of circuits in order to choose the right cable for the installation. A sheathed cable, often known as NM (non-metallic) cable, or Romex (named after a popular brand) is designed specifically for certain circuit configurations and amperage loads.

For a 15-amp circuit, 14-gauge wire is the standard, and for a 20-amp circuit, 12-gauge wire is the norm. For a simple receptacle outlet circuit, the cable will normally have two conducting wires—a white neutral and a black "hot" wire—plus a bare copper grounding wire. This cable usually carries a label that says "12-2 with ground" (12-gauge wire, two conductors, plus a grounding wire). But if the circuit is linking three-way switches, or is being used for certain light fixture configurations, the installation may call for three conducting wires, plus a ground. These three-wire cables generally have two hot wires (red and black) and a white neutral wire, plus the bare copper grounding wire.

When a cable is being run through walls without finished surfaces (such as in an unfinished garage or attic), or when it must be mounted on the surface of the wall, the electrical code may forbid the use of NM cable. Instead, you'll need to run the wires through metal or plastic conduit, or a metal-sheathed cable known as BX cable.

Safety Considerations

In most municipalities, work that involves running and connecting wires requires a building permit, as well as an on-site inspection. In some instances, a DIY electrician is allowed to do such work, as long as it is being performed in their own home. Sometimes a short homeowner's electrical exam is required to obtain a permit, however.

It's important not to bypass the permit and inspection process. The process exists to ensure that the work is done safely and that, in this case, the wire gauge is sufficient to handle the amperage load, and the cables are routed properly through the studs.

When to Call a Professional

Running NM cable for new or extended circuits is not a difficult job, but the final hookup of outlets, switches, and circuit breaker connections requires a specific skill set. It's advised that you call an electrician to make the final connections if you aren't fully confident in your skills. Furthermore, local code sometimes requires a licensed electrician to conduct work on the service panel. You may also want to call an electrician for any long or complicated cable runs, as well.

Materials and tools to run an electrical wire

The Spruce / Hilary Allison

What You'll Need

Equipment / Tools

  • Non-contact circuit tester
  • Straightedge
  • Pencil
  • Drywall saw
  • Stud finder (if needed)
  • Safety glasses
  • Dust mask
  • Drill with 1/2-inch bit
  • Circular saw with masonry blade (for plaster walls)
  • Shop vacuum
  • Tape measure
  • Wire cutters
  • Hammer
  • Drywall finishing tools


  • NM cable
  • Metal nail guards
  • Cable clamps (where needed)
  • Metal nail guards
  • Cable staples (where needed)
  • Drywall screws
  • Drywall joint tape
  • Drywall joint compound


How to Run Electrical Wiring

This demonstration shows one of the simplest and most common applications for running new wire: extending the circuit from an existing outlet to a new outlet location in a finished wall.

  1. Turn Off the Power

    For safety purposes, turn off the circuit breakers that control any associated live wiring in the wall where you'll be working. Use a non-contact circuit tester on nearby outlets or switches to verify that the power is off.

    Put on your dust mask and safety glasses.

    Turning off the power supply

    The Spruce / Kevin Norris

  2. Open Up the Wall

    With finished walls, you'll need to cut through the surface layer to gain access to the studs in order to run cable through them.

    Begin by marking a pair of cutting lines across the wall, from the electrical source to the destination box. Your goal is to remove as little drywall as possible, but the removed section needs to be wide enough so to bore holes in the studs with a drill. A section about 6 to 12 inches wide is usually sufficient. After marking, use a drywall saw or similar tool to cut out a channel of drywall between studs.

    When you are running cables vertically through the wall, you'll be removing the entire vertical section of drywall between two studs. Begin by using a stud finder to locate the studs, then cut away a vertical section of drywall from the stud cavity where you want to install cable. The large removed section of drywall can be saved to use for patching the wall when the cable work is completed.


    It can be difficult to open up walls that are made with plaster and lathe rather than drywall. One method is to use a circular saw fitted with a masonry blade set only about 3/4 inch deep. Cut horizontally along the wall surface to cut through the plaster and lathe and remove a section of the wall surface. Repairing the wall after the cable installation can be done with drywall.

    Drywall saw cutting wall open to run electrical wire

    The Spruce / Kevin Norris

  3. Bore Holes for Cable

    Near the center of each stud, drill a 1/2-inch hole where the NM cable will run. According to code regulations, the holes need to be set back at least 1 1/4 inches from the front edge of the studs, or, you will need to use metal plates nailed to the fronts of the studs to protect the cables from accidental penetration from screws or nails. Many electricians follow both guidelines—both setback and protective plates.

    When drilling holes, try to follow a straight line. Any deviation from a straight line makes it harder to pull cable. To ensure straight holes, hold the drill inside the stud cavity as you drill horizontally through the studs.

    After drilling all holes, clean out the wood chips and sawdust with a shop vacuum.

    Auger bit mounted on drill to give space for electrical wire to run through wall

    The Spruce / Kevin Norris

    Drill driving holes in wall studs for the electrical wire to run through

    The Spruce / Kevin Norris

  4. Cut and Pull the Cable

    Measure and cut a length of cable to run from the source to the destination, allowing a full foot of excess at each end. Beginning at one end of the cable run, thread ("pull") the cable through the first stud, across the wall cavity, through the next stud, and so on.

    Before pulling long stretches of wire, unravel and straighten out the coil of cable. This will help make the pull go more smoothly.


    Where you are running cable from an upstairs room to a downstairs room through floor plates, a drill bit extender can be useful for drilling the holes, and a fish tape is often helpful for pulling the cable. Pros often use a fish tape for long vertical pulls to avoid removing drywall altogether, except for small access holes necessary for drilling through the wall plates.

    At each end of the cable run, insert the end of the cable into the electrical box, using whatever cable clamps are necessary. Plastic boxes usually have preattached grip clamps; metal boxes may require an additional cable clamp that fits into an available knockout opening in the box.

    Yellow electrical wire pulled through wall studs

    The Spruce / Kevin Norris

  5. Attach Nail Guards

    Metal nail guard plates can be placed over the edges of studs to protect the wiring against accidental penetration from nails or screws. They also serve to reinforce the strength of the stud where it has been drilled.

    Although the code does not require nail guards if the holes have been bored with the proper 1 1/4-inch setback, it's a good idea to install them as a safety measure.

    Now, attach cable staples as needed: According to the electrical code, cables must be firmly anchored within 8 inches of each electrical box and every 4 1/2 feet if they run vertically along a stud.

    On horizontal runs, if the last hole falls more than 8 inches from the electrical box, secure the cable to the stud near the point where it emerges from the box, using a plastic wire staple. A vertical cable run should also be anchored to a stud with staples spaced no more than 4 1/2 feet apart along its length.

    Metal nail guard plates hammered to side of wall studs to protect wiring holes

    The Spruce / Kevin Norris

  6. Patch the Wall

    The final step is to patch the wall where it was channeled out to install the cable.

    Cut a drywall patch using a straightedge and utility knife, then insert it in the open channel and attach it to the studs with drywall screws. Where necessary, you can attach wood blocking alongside existing studs to provide a surface for attaching the edges of the wallboard patch.

    Finish the joints and screw heads with joint tape and drywall joint compound.


    If you plan to insulate an exterior wall before patching the drywall, be sure to leave enough slack in the wiring between the studs so there is no tension when the insulation is put in. Batt Insulation is commonly sliced or peeled in half so the wiring is encased in it.

    Drywall section placed back in wall with drywall screws drilled for wall repair

    The Spruce / Kevin Norris

  • How do you know if it's safe to drill into a wall?

    Before drilling, you must first visually inspect the wall for any possible obstructions. Outlets and light switches can give you clues as to where studs, wires, and pipes are located. You can also use a digital detection device to help you avoid any drilling mishaps.

  • Do the walls have to be opened to rewire a house?

    You do not have to tear down entire walls to rewire a house, however, making a few holes in the drywall may be unavoidable. It's best to hire a professional, if a full rewiring is necessary, as he or she will do their best to disrupt as little as possible.

  • How do you know if you screwed into a wire?

    Screwing into a live wire could cause serious injury, so it's best to avoid it at all costs by thoroughly inspecting the wall and using a digital detection device before you get started. However, if you happen to screw into a wire, chances are you will lose power to the outlet, and should be able to check this by using an AC voltage meter.