DIY Network

How to Install a Motion-Sensor Light Switch

A motion-detector switch will automatically turn on the lights whenever anyone walks into the room. This switch is a relatively simple device that's easy to install and operate.

More in Electrical

Step 1: Turn Off the Power

Identify the circuit to the light switch you'll be replacing, and turn the power off at the circuit breaker.

As an extra precaution, place a "Do Not Touch!" sign on the outside of the circuit box so that someone else doesn't unwittingly restore power to the circuit while you are working.

identify circuit of switch to be replaced

Courtesy of Lucie Rowe

Step 2: Test the Wires, and Remove the Switch

Remove the wall-plate from the existing switch, and test the wires using a circuit tester -- such as the audible-alarm tester used in our demonstration -- to be absolutely sure there is no power flowing to the wires you'll be removing. With our audible tester, a continuous beep would indicate that there is still power. The tester verified that the power was off.

With the power turned off, remove the screws that hold the old switch in place.

use circuit tester to be sure no power is flowing

Courtesy of Lucie Rowe

Step 3: Cut the Wires

The old switch has three wires connected at the back: a black wire, a white wire and a bare ground. The black and white wires will be connected to the new motion-sensor switch, but the ground will not be used.

Cut the wires at the back of the old switch.

know the wires in switch by color and use

Courtesy of Lucie Rowe

Step 4: Strip the Black and White Wires

With the old switch removed, strip the plastic insulation off the ends of the black and white wires using wire strippers.

wire stripper used to strip off plastic insulation

Courtesy of Lucie Rowe

Step 5: Connect the Wires to the New Switch

With the ends of the wires stripped, they can be hooked up to the new switch. Wrap the end of the black wire around one of the wire connections on the back of the switch. Repeat with the white wire. Secure the wires with wire-connectors.

Note: With the particular sensor-switch used in our demonstration, it made no difference which power-supply wire went to which connection on the back of the switch. Either wire could go to either connection. Follow the wiring instructions that come with the switch you purchase.

wire connectors give a safe secure connection

Courtesy of Lucie Rowe

Step 6: Tuck Wires Into the Box, and Secure the Switch

Tuck the excess wire into the back of the switch box (Image 1).

Position the connected motion-sensor switch into the switch box.

Secure the switch with the mounting screws provided (Image 2).

Step 7: Customize the Controls, and Reinstall the Wall-Plate

Note the customizing controls for adjusting the sensitivity and timing of the light activation. On our switch, the bottom adjustment controlled when the lights come on after someone enters the room. The bottom determines how long the lights stay on after everyone has left the room. Set these controls to your liking before installing the wall-plate (Image 1).

With the switch installed and adjusted, reinstall the switch wall-plate (Image 2).