Residential ceiling fixtures come in many different shapes, and people have devised many ways to attach them to the ceiling. Most of the time, a central threaded hollow rod holds a chandelier in place. Ceiling fixtures hang by two screws that attach the fixture base to the outlet box or to a mounting strap in the outlet box.
No matter how you suspend a fixture from the ceiling, the wiring is simple. Other wires may pass through the box, but you have to deal with only three wires: a colored wire (usually black), a white wire, and a green ground wire. These three wires are joined together with twist-on wire connectors.
Get someone to help you replace a ceiling fixture. After you loosen the screws that hold the existing fixture to the ceiling box, you have your hands full holding the fixture and trying to work on the wires. You may be able to pull off this juggling act with a light fixture, but if you're messing with a chandelier, you need another pair of hands to help.
To replace a ceiling light fixture, follow these steps:
Turn off the power.
You may find several pairs of wires in the ceiling box. Some of these wires may be wired to different circuits than the fixture you're working on. Be safe: Use a circuit tester or turn off the power to the whole house to ensure that all the wires in the box are dead.
Remove the light bulb cover and bulbs from the fixture.
Unscrew the screws or nuts holding the fixture base to the ceiling box.
Lower the fixture base and remove the electrical tape or wire nuts from the black (hot) wire, white (neutral) wire, and, if present, green (ground) wire.
Attach the wires from the new fixture with wire nuts to the corresponding wires in the electrical box.
Raise and position the new base plate so that you can screw the new bolts through it to attach it to the mounting strap.
Screw in new light bulbs, install the cover, and turn on the power.