Replacing a ceiling light fixture is often necessary because an old fixture has worn out, but it is also commonly done as part of a decor overhaul. A new light fixture can make a huge difference in the look and feel of a room. The work itself is usually quite easy, though anytime you are working with electricity there is some danger. DIYers should have a basic understanding of how electrical circuits work, and some experience with similar repairs, before attempting light fixture replacement.
Like plumbing, electrical repairs are often fairly simple if the system is relatively new and follows accepted practices. But they can become very difficult very quickly if the wiring system turns out to be old or in poor condition. Any time you take on wiring projects, be willing to call an electrician to bail you out if things get complicated.
Before You Begin
Turn the wall power switch controlling the light fixture to the OFF position. If there is any chance another person could turn on the switch while you are working (e.g., children or a spouse), then turn off the power at the main service panel.
Equipment / Tools
- Non-contact circuit tester
- New ceiling light fixture
- Wire connectors (wire nuts)
- Electrical tape (if needed)
Remove the Old Light Fixture
Remove the fixture shade or globe. How you do this will depend on the type of fixture you have. It can involve loosening little screws holding the shade in place, unhooking some mounting clips (as shown here), or just unscrewing a glass shade from the base of the fixture.
Once the ceiling fixture shade is removed, separate the fixture base from the ceiling box by unscrewing the mounting screws or the knurled knob that holds the fixture to the ceiling box.
Test for Power and Disconnect the Wires
Once the fixture base is separated from the ceiling box, check for power by using a non-touch circuit tester to make sure there is no current flowing to the wires.
Disconnect the light fixture from the circuit wires by unscrewing the wire connectors. The fixture may also have a copper grounding wire attached to the mounting strap on the box or to the circuit grounding wire. Disconnect this, as well. Set aside the detached light fixture.
Finally, remove the old mounting strap that is secured to the ceiling box. The new fixture will come with its own mounting strap.
Prepare the New Ceiling Fixture
Unbox the new ceiling fixture. Carefully remove the glass shade and set it aside in a safe place. Remove the plastic bag containing the hardware and set it aside, as well. Remove the fixture base from the box and examine its wires. Usually, it will have three wire leads: a black hot wire, a white neutral wire, and a green or bare copper ground wire.
If the light fixture has two or more lamp sockets, the black and white wires for each socket may not yet be connected together. If this is the case, join the white wires together with a wire connecter (usually included with the light fixture). Join the black wire leads together as well.
Read the light fixture instructions to determine how your light fixture will be mounted to the ceiling box. This can vary, depending on the size and weight of the light fixture. Sometimes, it will be a simple matter of screwing the light fixture base directly to the ceiling box. With other styles, a mounting strap is first attached to the ceiling box, then the fixture base is screwed to a mounting strap. With heavier fixtures, a threaded mounting tube is screwed into a hole on the mounting strap, then the fixture base is threaded over the tube and secured with a screw-on knob.
Install the Mounting Strap
If your light fixture requires the use of a mounting strap (it usually does), first examine the strap included with the new light fixture. It will have several small threaded screw holes in it, some of which are used to attach the strap to the ceiling box, others which will be used to support the light fixture base. The strap also has a larger threaded hole in the center; this is used if the light fixture is supported via a threaded mounting tube that screws into the strap.
Position the strap against the base of the light fixture to determine which screw holes will be used to support the fixture.
Then, attach the mounting strap to the ceiling box, using whatever screw holes line up with the ceiling box. The light fixture instructions may also give you guidance on the proper way to attach the mounting strap.
If your fixture requires it, screw the threaded mounting rod into the center opening on the strap. This is usually used for heavier lights, such as chandeliers and other hanging light fixtures.
Inspect the Circuit Wires
In most cases, the circuit wires you previously disconnected will be suitable to attach immediately to the new light fixture. You will see one wire with white insulation (this is the neutral), another with black insulation (this is the hot wire), and another that is bare copper or covered with green insulation (this is the ground wire). The circuit ground wire may be connected to a green ground screw in the back of the box.
Connect the Ground Wires
The ground connection on a ceiling light fixture can vary, depending on the type of fixture and ceiling box you have. Just remember that the light fixture's ground lead must have a metal pathway to the circuit grounding wire. It is dangerous to install a ceiling fixture without this ground pathway.
If your ceiling box is plastic, then the situation is easy: Just attach the circuit ground wire directly to the fixture's ground lead, using a wire connector.
It is a little more complicated if the ceiling box is metal. Here, both the box and the light fixture need to be connected to the circuit ground wire. A common way to do this is to loop the circuit ground wire around a green ground screw on the mounting strap or on the metal box, then attach the free end of the ground wire to the fixture's ground lead. Alternately, if the circuit ground wire is already attached to the metal box, the light fixture's ground lead can be attached to the mounting strap.
Connect the Neutral and Hot Wires
Join the circuit neutral wire to the fixture's neutral lead (both wires usually have white insulation), using a wire connector.
Do the same with the circuit and fixture hot wires (both usually have black insulation).
Mount the Fixture Base
With the wires connected, the next step is to attach the fixture base to the ceiling box. Depending on the style, the base may be attached with two long screws that thread into screw holes on the mounting strap, or with a knurled knob that screws onto the threaded mounting rod after the fixture base has been slipped over it.
When the installation uses long screws, it may take a bit of maneuvering to get the screws through the insulation in the base of the fixture and threaded into the ceiling box. The fixture may have keyhole-shaped screw slots that allow you to first insert the screws into the ceiling box, then push the fixture over the screws and twist the fixture slightly to lock it onto the screws. Once in place, tighten the screws down firmly so the fixture base is tight against the ceiling.
Install Light Bulbs and Shade
Complete the job by installing light bulbs (do not exceed the total wattage rating of the fixture). Turn the power back on, then turn on the light switch to test the operation of the fixture. If the fixture operates correctly, install the globe or shade, as directed by the manufacturer.
Do not use CFL bulbs (compact fluorescent lamps) in a fixture that has an enclosed shade or globe. They can overheat and fail and may pose a fire hazard.