Running Cable in Framing


Nonmetallic (NM) cable is acceptable under most building codes; check local requirements. To run armored cable you may need to drill larger holes. Turning corners is more difficult.

If a wayward nail pierces NM cable, the result could be disastrous. Place holes in the framing out of reach of drywall nails and attach protective plates at every hole.


About 3 hours to run cable and attach to seven or eight wall or ceiling boxes

Drill, 3/4-inch spade bit, screwdriver, strippers, lineman's pliers, hammer, tape measure, level

Drilling, stripping cable sheathing and wire insulation, attaching staples

Double-check that all the boxes are correctly positioned; clear the room of all obstructions.

Correct cable, staples appropriate to cable type, nailing plates

Installing NM Cable
NM cable should route where it cannot be hit by nails driven into the wall. 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.

Step 1

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 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

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

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

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

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.

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shahidny50gmai wrote:


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