How to Add a Light Inside an Under-Stair Closet

Locate the main electrical panel for your home. Identify the circuit breaker that controls the area where you will be working. Flip the breaker to the 'OFF' position to ensure no power is flowing to the existing wiring.

Determine the desired location for the new light fixture in the closet ceiling. Use a stud finder to ensure there are no joists or obstructions in the way. Trace the outline of the electrical box onto the ceiling. Carefully cut out the opening using a drywall saw. Insert the electrical box into the opening and secure it according to the manufacturer's instructions, ensuring it is flush with the ceiling.

Determine the most efficient path to run the new electrical cable from where the switch will be installed to the new ceiling box. Drill holes through studs or joists as needed to pass the cable. Ensure the cable is secured at regular intervals with cable staples as required by local electrical codes. Leave sufficient slack at both the switch and fixture locations for making connections.

Choose a convenient location for the light switch on the closet wall, typically near the entrance. Use a stud finder to ensure you are not drilling into a stud or other obstruction. Mark the outline of the electrical box onto the wall. Cut out the opening using a drywall saw. Insert the electrical box and secure it, ensuring it is flush with the wall surface.

Carefully strip about 6-8 inches of the outer sheathing from the electrical cable. Strip about 3/4 inch of insulation from the ends of the black (hot), white (neutral), and green or bare (ground) wires. Connect the wires from the cable to the corresponding terminals on the light fixture according to the fixture's instructions (typically black to brass screw, white to silver screw, and ground to green screw). Secure all connections with wire nuts.

From the switch box, pull the electrical cable that runs to the light fixture. Strip about 3/4 inch of insulation from the black, white, and ground wires. Connect the black wire from the cable to one terminal on the switch. Connect the black wire coming from the power source (if applicable, or another cable if it's a multi-way switch) to the other terminal on the switch. Connect the white (neutral) wires together using a wire nut, and connect the ground wires to the ground screw on the switch and to the electrical box.

Carefully tuck all the connected wires into the electrical box. Align the light fixture with the electrical box and secure it using the mounting screws provided with the fixture. Ensure the fixture is firmly attached to the ceiling.

Place the switch plate over the newly installed light switch and secure it with the provided screws. Attach any decorative trim or cover that came with the light fixture to conceal the wiring and mounting hardware, ensuring it sits flush against the ceiling.

Return to the electrical panel and flip the circuit breaker back to the 'ON' position. Go to the closet and operate the new light switch to ensure the light fixture turns on and off correctly. Check for any unusual sounds or smells, which would indicate a problem.