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How To Install Photocell Switches

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If you want to save money on electric bills, install a photocell switch, also called dusk to dawn switches. Photocell switches control the lights by measuring the amount of light around the object. You should easily be able to install a photocell light switch by following these steps.

Prepare To Install the Photocell Switch

To install the photocell switch, gather these items:

  • plastic gloves 
  • step ladder (optional)
  • Phillips head and flat-blade screwdriver
  • needle-nose pliers
  • voltmeter
  • wire strippers
  • wire nuts
  • electrical tape
  • silicone sealer 

Turn off power to the fixture you will be working on, and place tape over the breaker. Breakers commonly have labels to tell what they control, or you may need to keep trying breakers until you get the right one. You may prefer to place a sign on the panel door to say you are working on the light.

Disconnect the Fixture

Let the lights cool if they have been operating. Set up a step ladder to reach the fixture, if necessary. Detach the bulbs and cover, if applicable. Use the screwdriver to loosen the bolts on the fixture, being certain to keep one hand on it while you loosen the second bolt.

Before you continue, run a voltmeter over the wires to ensure no current is running to them. You should see a black wire and a white wire. Untwist the wire nuts, remove the fixture, and lay it on a flat surface.

Install the Photocell Switch

Look for a round knockout hole on the front of the fixture, and insert the blade of the screwdriver into the slit. Remove the knockout by tapping the screwdriver with pliers.  

The photocell switch should have a metal lip or gasket and a threaded metal end. Slide the metal end through the hole in the fixture, and feed the fixture wires through the gasket so they sit firmly against the photocell base. Strip about three-eighths inch of insulation from the wires on the fixture.

Thread the small lock nut from the back of the fixture, and use pliers to tighten the nut. Spread a layer of sealer around the knockout to keep out water. 

The photocell will have three wires: red, black, and white (neutral). Wrap the white wire around the white wire of the fixture, and secure the connection with a wire nut.

Twist the black wires from the wall and the fixture together. Then twist the red wire and black wire of the fixture together, and secure the connection. Cover the connections with a three-inch strip of electrical tape where the wires and nut connect.

Reinstall the fixture and hardware, and test the light by placing a strip of tape over the eye. If you wired the light correctly, it should come on in several minutes. Adjust the metal band as needed for activation.

If you need assistance with this or any other project, contact a qualified electrical service in your area.