Replacing a light fixture is relatively simple. In fact, the biggest problem you'll probably encounter is the mechanical complexities of attaching a new fixture to older mounting hardware.
In this article, we'll show you how to replace an incandescent light fixture. The simplest fixture installation uses a fixture strap secured to the electrical box. Connect white wire to white and black to black.
Check out the next page for the first step.
1. Cut the Power
Before you replace or repair any light fixture, deenergize the electrical circuit by pulling the appropriate fuse or by tripping the proper circuit breaker.
2. Remove the Light Cover
Take off the light cover, unscrew bulb(s), and disassemble all mounting hardware. Usually there are just screws holding the fixture against the wall or ceiling. If the light fixture has no visible mounting hardware, it could have a decorative feature that doubles as a fastener. Take off the mounting hardware and withdraw the fixture from the electrical box.
3. Disconnect the Fixture
Disconnect the lamp fixture wires from the circuit wires. If the wire joint is fused together with old insulating tape, cut the wires close to tape. Caution: If wires or insulation coming into electrical box are brittle or frayed, that part of circuit should be professionally rewired. Once you remove the old fixture, examine the electrical box and the new fixture to determine which of the following installation procedures you should use for additional steps.
For fixture installation in standard electrical box:
Make sure you have about 3/4 inch of bare copper conductor on the end of each line wire before you start to connect the wires of your new lighting fixture. If necessary, remove enough insulation from the line wires so you can twist each line wire end together with the end of each light fixture wire, white wire to white wire and black to black. Screw the wirenut tightly over each pair of twisted ends. Hold onto the fixture to support its weight until you attach the mounting screws; otherwise, you might break a connection or damage the fixture wires.
If fixture has more than one socket:
Connect the black wire from each socket to the black line wire and the white wire from each socket to the white line wire. When three or four socket wires are joined to the line, use the larger wirenut.
4. Insert the Screws
Mounting screws of proper length are typically included with your new lamp fixture. Screws 2 or 21/2 inches long are sufficient for most fixtures. Insert the screws into the attachment screw holes in the electrical box, and tighten each screw four or five turns to hold it in place. Mount the fixture by passing fixture's keyhole slots over the screw heads. Then rotate the fixture enough so the screws are forced into the narrow parts of the keyhole slots.
5. Tighten the Screws
Tighten the screws, being careful not to overtighten them; they should be just snug enough to hold the fixture firmly in place. If you tighten the mounting screws too much, you may distort and misalign the fixture. With the fixture mounted properly, screw in the bulbs and attach the globe or cover.
6. Reassemble the Fixture
Replace the fuse or trip circuit breaker back on.
Some fixtures are mounted with a short piece of threaded pipe, called a nipple. To mount this type of fixture, screw the nipple into the center hole of the strap, and set the fixture onto the nipple. Screw a cap nut onto the nipple to hold the fixture in place.
Other light fixtures are not strap-mounted. Instead, a nipple is connected to the box stud with a reducing nut or an adapter called a "hickey." A reducing nut is threaded at one end to fit the stud and at the other end to fit the nipple. To mount a fixture that uses a reducing nut, screw the nut onto the stud and the nipple onto the nut. Set the fixture onto the nipple, set the fixture into place, and screw a cap nut onto the nipple to hold the fixture in place. To mount a fixture with a hickey, screw the hickey onto the stud, and then mount the fixture the same way.
What if the fixture you need to replace is fluorescent, not incandescent? On the next page, we'll discuss the finer points of replacing fluorescent lighting fixtures.