Drilling for Cable

Once boxes are in place, you’re ready to run cable to each of them. It’s rather like connecting dots with a pencil line. To prevent screws or nails from puncturing cables, drill in the middle of studs or joists whenever possible. If the edges of any holes you drill are less than 1 1⁄4 in. from the edge of a framing member, you must install steel nail-protection plates. Always wear eye protection when drilling.

Drill for cables running horizontally (through studs) first. It doesn’t matter whether you start drilling at the outlet box closest to the panel or at the last outlet on the circuit. Just be methodical: Drill holes in one direction as you go from box to box. However, if you’re drilling for an appliance that has a dedicated circuit—and thus only one outlet—it’s usually less work to drill a hole through a top or bottom plate and then run cable through the attic or basement instead of drilling through numerous studs to reach the outlet.

If possible, drill holes thigh high 1. Partially rest the drill on your thigh so your arms won’t get as tired. This method also helps you drill holes that are roughly the same height—making cable-pulling much easier. Moreover, when you drill about 1 ft. above a box, you have enough room to bend the cable and staple it near the box without crimping the cable and damaging its insulation.

For most drilling, use a 6-in., 3⁄4-in.-diameter bit. Use an 18-in. bit to drill lumber nailed together around windows, and doorways 2. Using an 18-in. bit is also safer because it enables you to drill through top plates without standing on a ladder. Standing on the floor is a big advantage, as the reaction torque from a heavy-duty drill can throw you off a ladder if a bit binds up 3.

Excerpted from Wiring Complete, 3rd Edition (The Taunton Press, 2017) by Michael Litchfield and Michael McAlister

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