Install a Photoelectric Switch

A photoelectric switch.
  • 1 hours
  • Beginner
  • 50
What You'll Need
Photoelectric switch
Wire strippers
Needlenose pliers
Screwdriver (Phillips and Flat Head)
Voltage tester
Electrical tape
Wire nuts
Silicone sealant

Installing a photoelectric switch, also known as an electric-eye or photocell, is an easy task that can save you money on your electric bill in the long run. Follow these easy steps and you won't have to remember to turn the lights on when it gets dark again. Keep in mind throughout the instructions that "photocell" is just another name for the photoelectric switch.

Here are instructions for two different installation techniques. The first is installing a new light fixture that comes pre-wired with a photocell. The second is adding a photocell to an existing light fixture.

Installing a Photocell to a New Light Fixture

Step 1 — Turn Off the Power

Turn off the breaker to the circuit you will be working on. Place a strip of electrical tape over the breaker that controls the circuit. You can also tape a sign to the door of the electrical panel box stating "Keep Out - Working on Electric!"

Step 2 — Remove the Fixture

Remove the bulbs from the existing fixture. Use the screwdriver to remove the bolts holding the fixture to the box. As you remove the second bolt, make sure to hold onto the fixture so it doesn't fall away. With the fixture hanging by the wires, use your voltage tester to ensure that the power is still off.

While holding the fixture, unscrew the wire nuts and separate the wires. There should be one black and one white wire. Remove the old fixture.

Step 3 — Install the New Fixture

Light fixtures with pre-wired photoelectric switches are installed just like a regular fixture. If your new fixture requires a mounting bracket, it will come packaged with one and instructions on how to install it. It may also come with a soft, waterproof gasket. Install it as per the instructions as well.

Step 4 — Wiring

Use the needlenose pliers to cut away the weathered part of the exposed wire ends in the box. Use the wire strippers to strip away about 3/8" of insulation from the wires in the box. On most wire strippers there is a guide on the side that shows how much insulation should be stripped.

To make it easier, line up the black wire of the new fixture and the black box wire and twist them together using the needlenose pliers. Place a wire nut over them and screw it on until tight. Do the same thing with the white wires. Cut a 3" piece of electrical tape and tightly wrap it around the wire nut where it meets the wires.

Step 5 — Finish it Up

Gently push the wires back into the box. Connect the fixture to the box with the bolts supplied. It may be easier to start tightening the bolts by hand so you can line the holes up and then tighten everything down using the screwdriver. Also, make sure no wires are outside of the box.

Install new light bulbs as rated by the fixture's manufacturer. Now turn the power back on, the lights should automatically come on and stay on for a few minutes, even if it's daytime. You are all set to clean up.

Step 6 — Test it Out

You can test your photoelectric eye by placing strips of electrical tape over the "eye." Make sure it’s completely covered. If it's working properly, the light should turn on within a few minutes.

Installing a Photocell to an Existing Light Fixture

Many exterior light fixtures come with "knockouts" to make installing photocells or motion sensors easier. These instructions are for a fixture with a "knockout." Follow Steps 1 and 2 above, as they are the same here.

Step 1 — The "Knockout"

With the fixture removed, you will see a "knockout" somewhere on the plate or the face of it. It will be round and it may have a slit through it so you can unscrew it with a screwdriver. The photoelectric switch should come packaged with a rubber ring gasket. Fit the wires through the gasket and move the gasket over the threads so it's right up against the base of the photocell.

Guide the wires through the "knockout" hole on the fixture. With the wires through the hole, use the locknut that came with the photocell to secure it to the fixture. On the inside of the fixture, use the silicone sealant to seal around the knockout where the photocell is located. This will help keep water out.

Step 2 — Wiring

There should be a black, white, and red wire coming from the photocell. The white wire gets connected to the white wire of the fixture and the white wire of the wall box. (See the wiring step above for instructions on connecting wires.) The black wire gets connected to the black wire of the wall box. The red wire gets connected to the black wire of the fixture.

Step 1 — Finish it Up

Follow steps 6 and 7 above, and you're done.

Adding a photoelectric switch to your exterior lighting will save you money and increase your sense of safety around your home. However, if you are unsure of whether or not you could benefit from installing a photoelectric switch, read this article describing some of their uses and benefits here.

Click here to purchase photoelectric controls.

Dave Donovan is a freelance copywriter living in Atco, N.J. An electrician for 15 years, an injury forced him to pursue his true passion - writing.