How to Install an Electrical Box in a Finished Wall

Not all fixtures need to be attached to a wall stud or joist. Lightweight fixtures can hold up on plaster or drywall if you have a remodel electrical box . Installing these handy boxes only takes about 15 minutes and they give you the freedom to decorate your space exactly how you want. Try your hand at this small electrical project using our step-by-step instructions below.

Before you get started, plan the job carefully, as running cable through walls covered with drywall or plaster can be difficult. Remodel boxes (also called cut-in or old-work boxes) clamp to the drywall or plaster rather than attach to a framing member, making the work easier. However, they are only as strong as the wall surface to which they are clamped. If the drywall or plaster is damaged, cut a larger hole and install a box that attaches directly to a stud or joist.

What You'll Need

Equipment / Tools

Stud finder

Torpedo level

Utility knife

Screwdriver

Hammer

Drill

Drywall saw (or rotary cutter or jigsaw)

Cable clamps, if needed

Materials

Remodel boxes acceptable under local code

Instructions

For your safety, turn off power before starting this project. If the box does not come with a cardboard template, hold its face against the wall, use a torpedo level to make sure it is straight, and trace it. With a utility knife cut the line deeply enough to cut through the drywall paper.

drywall saw

Cut the hole with a drywall saw. Cut to the inside of the knife cut to prevent fraying the paper. Test to make sure the old-work box fits in the hole.

thread cables remodel box

Thread Cables

Run cable through the hole. Strip 8 to 12 inches of sheathing and run the cable into the box. Tug to make sure the cable clamps tightly.

wall insert remodel box with cables

Insert Box

Push the box into the hole. If it fits tightly, do not force it or you may damage the drywall. If needed, use a utility knife to enlarge the hole in your wall.

securing remodel box

Secure Box to Wall

This type of box has wings that extend outward when you start to drive the screw, then grasp the back of the drywall as the screw is tightened. Tighten the screw until you feel resistance and the box is firmly attached.