How to Install a Ceiling Electrical Outlet Box on a Joist

Determine where in the room you want to install the new electrical box. Go up to the attic and poke a hole through the drywall with a drywall saw, next to the ceiling joist for the electrical box mounting.

Return to the room. Hold the electrical box against the ceiling with one edge lined up with the hole you poked in step 1. Trace around the electrical box with a pencil.

Determine which knockout hole to remove in the electrical box to allow the electrical cable to enter the box. Hold a screwdriver over the knockout hole. Hit the screwdriver's handle with a hammer. Insert a cable connector into the knockout hole.

Cut the drywall, following the pencil tracing, with a drywall saw. Insert the electrical box into the opening you created. Press the electrical box's nailing edge against the ceiling joist. Hold the electrical box's edges even with the drywall ceiling's surface.

Hammer nails through the holes in the electrical box's nailing edge to secure the electrical box to the ceiling joist.

Send a fish tape through the knockout hole you removed in step 3, across the attic and down to the power supply source. You may need to drill a 1/2-inch hole, with a boring bit, through a top plate, the 2-by-4 board running horizontally over wall studs, to run the fish tape down to the main electrical service panel.

Attach a 12- or 14-gauge electrical wire to the fish tape's hooked end. Ensure the wire gauge of the new wire matches that already installed in the rest of the house. Return to the electrical box and reel the fish tape, with cable attached, back in. Pull the electrical wire until it extends 6 inches into the electrical box and has enough room to hook up to the main electrical service panel at the other end.