Disconnecting a ceiling light fixture is not a difficult task. Ceiling light fixtures mount to either a junction box in the ceiling or a bracket that mounts to the junction box. The junction box mounts to a ceiling joist, support beam or a bracket which spans the two adjacent ceiling joists. The fixture's power supply most often comes from either a wall-mounted switch or adjacent light fixture. There are many different types of ceiling light fixtures and their installation methods can vary.
Turn off the power to the light fixture. If the light fixture operates from a switch, turn on the fixture and proceed to the circuit breaker box. Turn off the applicable circuit breaker and/or breakers until the light fixture goes off. As some ceiling junction boxes have more than one circuit in them, do not assume that all the wires in the box are dead. The best way to ensure the junction box is void of electricity is to turn off the main breaker in the breaker box. This will eliminate any guesswork.
Set up the ladder under the light fixture. Use a ladder that allows you to reach the light fixture safely and take the time to set it up properly.
Remove the light fixture's globe and light bulb if applicable. Globes mount in varying ways. One method is holding them in place with three or four setscrews located around the globes rim where it meets the fixture. Use a screwdriver or your hand and loosen the screws. This will release the globe from the fixture. Another method uses a larger decorative bolt and washer that screws through the centre of the globe into the fixture. These are usually hand tightened but sometimes require a pair of pliers. Check the sockets with a non-contact voltage tester to verify there is no power present.
Remove the fixture's mounting screws. Use a Phillips or slotted screwdriver to loosen and remove the screws. The electrical wiring will support the weight of small fixtures. Check all the wires within the box with a non-contact voltage tester to verify there is no power present in the box. Let the fixture hang freely while disconnecting the wires. A heavier fixture requires extra support either by holding it with one hand while disconnecting wiring or by recruiting a helper to hold the fixture while the wiring is disconnected.
Disconnect the wiring. Most light fixtures have three wires. A common "black," a neutral "white" and a ground, which is either green or bare. Twist the wire nut off one wire, separate the wires and replace the nut onto the wire from the junction box. Disconnect and cap the remaining wires with wire nuts. Cover the box with a blank cover to conceal and protect the exposed wiring.
Protect your flooring by using a dropcloth or taping up the bottom legs of the ladder. Recruit a helper to simplify the project. An extra set of hands can be a valuable asset.
Take extreme caution working with electricity. If you have doubts about your ability to work with electricity safely, hire an experienced professional.