Electrical Fasteners and Clamps

In addition to cable and boxes, supplies for electrical wiring include tape, staples, or straps to secure cable to framing members, and clamps that secure the cables to boxes.

Light fixtures usually come with all the necessary hardware for fastening to the ceiling box. If you have old boxes, you may need to buy extra hardware.

Codes require that all exposed cable be tightly stapled to the wall, ceiling, or a framing member. Use staples when running cable in unfinished framing. For NM cable, buy plastic-insulated staples that are the right size for the cable.

To anchor metal conduit, hammer in drive straps every few feet. For PVC conduit or armored cable, use one- or two-hole straps; make sure they fit snugly around the cable or conduit.

When securing straps, avoid black drywall (or all-purpose) screws because they break easily. Wood screws cost more but are more reliable.

New-work plastic boxes have holes with plastic flaps that grab NM cable. With this type of box, you must staple the cable to a framing member near the box. Use these only in unfinished framing. When installing a remodel box or when installing a box that is exposed, the cable or conduit must be firmly clamped directly to the box.

A cable clamp comes in two parts: the clamp and the locknut. An NM cable clamp holds the cable using a strap with two screws; an armored cable clamp holds the cable using a single setscrew.