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electricity

Replacing a light fixture

The Dashing Wife has been asking me to replace the flood lights that shines in the back yard. The lights were CFL flood lights and they took a long time to warm up to finally shine bright. The LED lights we bought shine bright and don’t take any time to warm up.  I figured I could write up a quick blog post about replacing a light fixture.  The whole job took me about 35 minutes, with taking photos.

CFL flood light that I am going to replace

CFL flood light that I am going to replace

The first step is to check the power. Most light switches take power from the switch to the light fixture, though sometimes the power starts from the light and goes down to the switch and back (usually in older houses when the wiring goes through the ceiling). To be absolutely safe, turn off the breaker at the panel, but most times, as long as the switch is off there shouldn’t be power at the fixture.  That said, remember I told you to turn off the breaker, so don’t come crying to me if you get shocked.

The only tools you should need are a flat head screwdriver, a Philips head screwdriver, and a box cutter/knife. You may need a pair of wire cutters, and a pair of wire strippers. A power drill and voltmeter can’t hurt either.

Next, use a knife or box cutter to cut the caulk around the fixture (if there is any).

Cutting the caulk between the wall and light

Cutting the caulk between the wall and light

Undo the screws on the fixture, and pull it away from the wall (or ceiling). You should see three wires coming from the wall (you might see six wires if your light switch controls more than one fixture) connected to three wires on the fixture. One set of wires, the bare copper wire and the green coated wire might be connected to a green screw on wall, though they may be just connected to each other with a wire nut. The other wires should be connected to each other. The wires from the light fixture should be one black and one white, but the wires coming from the wall may be the same color (if you have extra wires coming out of the wall, be sure to keep them together). Note which wire was attached to the black wire to the fixture.

Wires in the light

Wires in the light

Anyway, disconnect the wires from each other and remove the fixture. If you didn’t turn the breaker off, you may want to avoid touching the copper ends of the covered wires. If you have a volt meter (you can pick up cheap one at an auto parts store), test the wires to see if you have voltage.

You can also test to see which wire is coming from the light switch (the hot wire) using the volt meter. Turn the power back on and touch one wire and the bare copper wire to see if it has voltage. If it does have power, that is the hot wire. Remember which is which and turn the power back off.

I have power to the top wire. (power should be between 120 and 140 volts in the USA.

I have power to the top wire. (power should be between 120 and 140 volts in the USA.

You will probably have to install some sort of bracket to support the new light. That should go in with a couple of screws, and then adjust the other part of the bracket to align with the new light fixture.

Installing the support bracket

Installing the support bracket

Then start attaching wires. First attach the bare copper wire and the green wire to the green ground screw. Then attach the black wire to the hot wire, and the white wire to the other wire. You may want to see if the new light has power before you attach to the wall, so turn the switch on and see if the light comes on. Then attach the light to the bracket.

After installing the foam gasket, connect the wires.

After installing the foam gasket, connect the wires.

If the fixture is outside, I recommend using some clear silicone caulk to seal the fixture from moisture. I usually put a liberal amount around the edge and then use my finger to make the seal better and complete.

A thick line of caulk, it goes on white and turns clear.

A thick line of caulk, it goes on white and turns clear.

The new LED light works like a charm

The new LED light works like a charm

That should be it, I managed to replace one fixture in about 30 minutes with “help” from my kids.