How to Run Cable in Framing
If you're expanding or adding to your home, learn how to run cable in framing. You can do it in just six steps!
Whether you're building a home addition or putting up a new wall, you're going to need some kind of power lines. Running cable directly through framing is a convenient (and, according to some codes, required) way to add power. This tutorial walks you through the fairly simple process.
Before you begin wiring, you'll need to pick a cable. Nonmetallic (NM) cable is acceptable under most building codes, but check local requirements before you begin to install it. To run armored cable you may need to drill larger holes, and keep in mind that turning corners is more difficult.
You'll need about 3 hours to run cable and attach to seven or eight wall or ceiling boxes. Make sure you're comfortable drilling, stripping cable sheathing and wire insulation, and attaching staples. Before you begin, double-check that all the boxes are correctly positioned and clear the room of all obstructions.
Editor's Tip: If a wayward nail pierces NM cable, the result could be disastrous. Where possible, add protective nailing plates. When working with engineered joists, check the manufacturer's information before cutting, drilling, or nailing. You could void the joists' warranty.
What You Need
- 3/4-inch spade bit
- Lineman's pliers
- Tape measure
- Correct cable
- Staples appropriate to cable type
- Nailing plates
Step 1: Drill Into Studs
Use a tape measure and level to mark holes in a straight line about 12 inches above the boxes. With a sharp spade bit, drill a 3/4-inch hole through the center of each stud.
Step 2: Uncoil and Thread Cable
Uncoil cable carefully from the box to prevent kinks. Pull the cable through the holes. The cable should be fairly straight but not taut.
Step 3: Anchor Cable
Within 8 inches of a plastic box or 12 inches of a metal box, anchor the cable in the middle of the stud with a staple. Drive staples every 2 feet where cable runs along a framing member.
Step 4: Cut Cable
Mark where you will strip sheathing and cut the cable. About 1/2 inch of sheathing should enter the box, and the wires inside the box should be 8-12 inches long. You can always trim them later.
Step 5: Open the Knockout
With a hammer and screwdriver, open the knockout. On some plastic boxes you remove the knockout entirely. For the one shown, crack open one end of the tab so it can grab the cable. A metal box may have a built-in clamp, or you may have to add a clamp before sliding in the cable.
Step 6: Add Protective Plates
Wherever a nail might accidentally pierce the cable, attach a protective nailing plate. Tap the plate into place. Attach a plate on both sides of the stud if needed.
Bonus: How to Drill Multiple Holes at Once
A standard 3/8-inch drill may overheat after drilling four or five holes. If you have many holes to bore, rent a 1/2-inch right-angle drill. When using it hold on tightly and brace yourself; it has high torque and can twist around, possibly causing injury.