How to Wire a Fluorescent Light Fixture

When replacing an incandescent bulb or an old light fixture with a new fluorescent light fixture, wiring it correctly is essential.

Step 1 - Prepare the Circuit Cable

Determine the length of the circuit cable that will run from the location of the switch to the location of the light fixture. Cut the cable accordingly and remove at least 4 inches of the cable sheathing on both ends using a utility knife to reveal the colored wires. Run the cable from the switch to the fixture location.

Step 2 - Prepare the Fixture

Remove the cover plate on the fixture to reveal the ballast, the starter, the socket, and the wiring. Remove the knockout cover and secure the cable clamp inside the opening on top of the light fixture, then insert the unsheathed wires of the cable into the cable clamp. When all colored wires are inside the fixture, tighten the cable clamp. Mount the fixture onto the ceiling joists and tighten the screws.

Step 3 - Connect the Cable Wires to the Fixture Wires

Locate the fixture wires colored black, white, and green/bare. Sometimes, there will be no green or bare fixture wire. Strip one inch of the wire insulation on all insulated black and white wires from the fixture and cable. Connect the stripped white wires together, cover them with a wire nut and twist until no bare wire is visible. Do the same with the black wires. Near the knockout hole is a small ground screw. Hook the bare wire from the cable to this screw. If the fixture also has a ground wire, hook it to the screw as well. Recheck all connections for errors.

Step 4 - Install the Fluorescent Tubes

Make sure that the starter is in place and attach the cover plate back on the fixture. Install the fluorescent tubes on the fixture according to the manufacturer’s instructions. If there is a diffuser provided, attach it as well after the tubes are in place.

Step 5 - Wire the Circuit Cable to the Switch

Assuming that a switch is already available and has been wired to the electrical source, turn off the breaker in the main service panel. This will eliminate the chances of accidents from electric shock. Remove the light switch cover and remove the two screws on the switch. Pull the switch off the electrical box. There are two brass screws on the switch. A black wire from the main electric source is connected to one of the screws. Strip 1 inch of the insulation on the black and white wires from the cable.

Hook the black wire on the second brass screw and tighten it. Hook the bare wire to the green screw on the other side of the switch. Find the white wire coming from the main service panel and connect it to the white wire on the cable using a wire nut. Screw the switch back to the electric box and re-attach the switch cover.

Turn on the main service panel and the switch to test if the light fixture works.