How to Wire an Outlet
Time Required: Over 1 day
Running electrical wires behind your walls is a great way to add an additional outlet or switch right where you need it. This project guide will explain how to wire an outlet and walk you through the steps of running basic nonmetallic (NM) electrical wire behind the walls.
Tools & Materials
- Use a stud finder to ensure the location for your new device isn’t adjacent to a stud.
- Hold the electrical box up to the wall in the location where it will be installed.
- Trace around the box with a pencil to mark the area to be cut. Use a level to ensure the outline is straight.
- If you’re running cable through the ceiling, use a screwdriver or power drill with an 1/8-inch bit to carefully drill a hole through the ceiling above the new wall box location. If you’re running cable through your basement or crawl space, drill into the baseboard or floor right next to the baseboard instead.
- Insert a stiff wire or straightened coat hanger into the hole.
- In your attic or basement, look for a 2 x 4-inch beam adjacent to the protruding stiff wire. In an attic, this beam is the top of the wall, known as the top plate. In a basement, it’s the bottom of the wall, known as the bottom plate.
- If the 2 x 4 is under a piece of plywood, or covered in some other way, measure 2 ½ inches from the reference wire toward the 2 x 4 and drill there. That should put the hole in the middle of the plate.
- Check with a flashlight to make sure there are no electrical wires or plumbing pipes behind the walls where you will be working.
- Drill a 1/2-inch starter hole at one corner of your electrical box outline.
- Starting at the hole, cut along the outline with the drywall saw. It’s OK if the edges of the opening are rough. You can conceal the opening with a wall plate.
- If you’re going through the attic, use the spade bit to drill a hole through the top plate, directly above the new electrical box location. If you’re running cable through a basement or crawlspace, drill a hole in the bottom plate directly below the box.
- Feed your fish tape into the wall opening, pushing it up into the hole you made in the top plate. If you’re running cable through a basement or crawl space, push it down to the hole in the bottom plate. You may need to insert the end of a coat hanger into the hole to pull the end of the fish tape through the hole.
- Should you encounter a fire block, proceed with Step 6. If you do not encounter a fire block, go directly to Step 7.
A fire block is a horizontal beam of wood running between the wall studs. You can drill a hole through the fire block or create a notch to accommodate the wire.
To drill a hole:
- Insert a long, flexible drill bit through the opening for the electrical box and position it on the center of the fire block.
- Drill through the fire block.
To cut a notch:
- Cut into the drywall at the location of the wall block.
- Use a sharp chisel and a hammer to cut a 3/4-inch wide x 1-inch deep notch in the fire block as a conduit for the cable. Pull the cable past the fire block following the instructions in Step 7.
- After you have fished the cable through the notch, cover the notch with a metal nail plate to protect the cable from nail damage.
- Patch over the drywall hole.
- From the attic, basement or crawl space, use electrical tape to secure one end of the cable to the hook on the fish tape.
- At the wall opening, carefully and steadily retract the fish tape, pulling the cable to the wall opening. Don’t create friction that can tear the cable’s sheathing, and carefully avoid kinks that could damage the cable.
- Before beginning your project, decide whether to pull power for your new outlet or switch from an existing outlet or directly from your breaker panel. Either way, double check that adding a new device won’t overload the circuit.
- Diagram your wiring path. Often the simplest approach is to run cables to either the attic directly above the new outlet or switch, or to a basement or crawl space below.
- If you aren’t able to install electrical wiring behind walls due to ductwork or plumbing, an alternative solution is to conceal wires using raceway, which runs along the surface of walls and can be painted to blend with your decor.
- Turn off the electricity at the breaker panel to the outlet or circuit breaker you will draw power from. Use a voltage tester to confirm the power is off at the outlet or breaker.
- Make sure a new device will not overload the circuit from which you draw power.