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How to Install a Motion Detector for Outdoor Lighting

Motion detector lights automatically light up an area during the night to make you feel more secure. The detectors sense infrared heat waves from moving objects and signals the light or lights to turn on. The lights remain on unless the detector continues to sense movement in the detection zone or until the preset timer allows them to switch off. The lights deactivate during daylight hours by a photocell. Continue reading to find out how to install a motion detector for your lights.

Installing a motion detector

Follow these steps to install your motion detector.

  1. Turn off the power
  2. Wire the fixture
  3. Mount the fixture on the house
  4. Adjust the sensor so it does not pick up small animal movements
  5. Install a remote sensor if this is your choice

Preparing for the new light

Turn off the power to the circuit of the room you are working in at the fuse box. Next, remove the old light if you are not adding the motion detector to it. Make sure the junction box is attached to the house and use your voltage tester to make sure the power is still off.

Wiring the fixture

Run the sensor light wires through the cover plate gasket. Next, connect those wires to the existing house wires per manufacturer’s instructions using wire connectors. For added security on the connectors, use electrical tape.

Mounting the fixture

Secure the fixture to the junction box with the screws provided. Apply clear silicone caulking around the top. Do not apply it to the bottom so water can escape from the bottom.

Adjusting the sensor

Move the sensor to the desired field of view and set the distance range, timer, and automatic shut off for the light. Turn the circuit on at the fuse box. Walk across the sensor’s field of view to activate it. Make readjustments if necessary.

Installing a remote motion detector

If a large motion detector does not look appealing on your home, consider purchasing a remote style detector to connect to a new or existing light Before you get started, turn off the power to the circuit of the room you are working in at the fuse box then follow these steps for installation

Cutting holes for junction boxes

The sensor and light fixture must have an electrical box set into the wall. Boxes can be rewired at existing light fixtures. If the interior wall is unfinished, purchase boxes that are mounted on an adjustable bar. The bar will allow you to position the box anywhere between the studs. Use remodeling boxes that clamp to the siding if the wall is enclosed.

Holding the box against the wall, trace around it with a pencil. If you are working with stucco or brick, use a one-quarter inch masonry bit to drill holes around the circle. Break out the middle with a chisel. If it is stucco, cut the metal mesh with snips and the sheathing with a jigsaw.

If you have wooden, cement board or hardboard lap siding, drill a hole in the center of the board to provide a flat surface to mount the junction box. If you have vinyl or another type of narrow siding, use a mounting block to fit over the lapped edges. To cut a hole in siding, drill a three-eighths inch hole into the wall then cut the circle with a jigsaw.


Before running fixture wires to the junction boxes, plan how you will wire the system. The simplest way is to draw power from the switch box, run wires to the sensor and then to the light fixtures. Another option is to run the wires to a fixture then the sensor. Choose a method that will make running the wires easier. Whichever you choose, you can add as many motion sensor lights as you like if it does not go over the watt rating of the sensor.

Running cable

Once you know where you plan to run the fixture wires, you can start making the path. Make sure the new wires match the gauge of the existing wire. Also, avoid paths that will require you to drill holes in tight areas or through heavy framing. If the interior walls are unfinished, run the wires in the upper walls or the rafters to lessen the risk of damage. Use a five-eighths inch spade bit for minimal drilling and a larger bit for more serious drilling. Once the path is created, run the fixture wires between the boxes. Fasten the wire to the framing with plastic staples placed eight inches apart.

Connecting the sensor and lights

Once the wiring is in place, take your time connecting the sensor and lights. If you are connecting to existing wires, cut the old bare ends and strip the insulation to expose new wire for new connections. Mount the light fixture per the manufacturer’s instructions. Connect the white wires (neutral), red or black wires (hot), and the green or bare copper wires (ground) with wire connectors. Turn the power on and set the sensor to test mode to ensure the system works correctly after the connections are made.

Built-in sensors

Some motion detector lights that have built-in sensors and will not require new wiring. They only need a few minutes for installation just like any other light fixture. Lights with built-in sensors operate a lot like floodlight motion detectors but are much more appealing.

Wireless motion detectors

Motion detector lights with wireless sensors work much like a remote for a garage door. The receiver screws into an existing light socket and the sensor is mounted elsewhere. The sensor sends a signal to its receiver to switch on the light.

Choosing a motion detector

Whether you are using it for security or convenience, there are three main things to consider when purchasing an outdoor motion detector light.

  • Distance is important to look at if you are using it for security purposes. You will want a detector that has the furthest range. Flood lights are the best for this purpose. If security is not your primary concern, a basic decorative or remote motion light will suffice.
  • Field of view is also necessary for security measures. Choose a detector that can sense motion as close to 360 degrees as possible to eliminate dead zones. A detector with an 180-degree view is good if it will be mounted on a wall.
  • Check the motion detector’s maximum wattage. Outdoor motion detectors are measured by the total number of watts the bulbs hold. If you are installing the lights for security, purchase a detector with as close to a 1,000-watt rating as possible.

Placing motion detectors

Consider installing motion detectors over walkways, doors, and driveways if you are looking for additional lighting. Patios, stairways, and swimming pools are also good places to install a motion detector. If you need improved security, light up all entry ways to your home including fence gates. Light security is no guarantee to keep intruders from approaching, although it is an inexpensive way to increase awareness.

It is most effective to mount the detector lights 6 – 10 feet above the ground to catch movement across the sensitivity zone. If you are connecting the sensor on pre-existing lights, consider purchasing a remote sensor to install a distance away from the light.

Gathering supplies

The supplies needed to install a motion detector include

  • Motion sensor light fixture
  • Light bulb
  • Wire stripper/cutter
  • Wire connectors
  • Electrician’s tape
  • Drill with bit
  • Jigsaw
  • Junction boxes
  • Clear silicone caulking

Testing your motion detector

After you have installed your motion detector, it is important to perform tests to make sure it works. Follow these steps

  • Locate the slide switch on the bottom of the sensor and slide it to the “TEST” position. Move the sensor adjustment halfway.
  • Turn on the power and the circuit wall switch. The lights will come on for 30 seconds then turn off unless there is movement in the detection zone.
  • Aim the detector where you want it to sense motion. Walk across this zone at the furthest point you would like the lights to turn on.
  • Grasping the lamp holders only, move the light bulbs so they do not interfere with the sensor. Aim the light bulbs away from the sensor and slightly down so that water does not fill the lamp holders.
  • Adjust the sensitivity
  • Move the switch from the “TEST” position to the selection specified by the manufacturer

Adjusting motion detector sensitivity

False alarms are created when the motion sensor is not pet immune and activates at the smallest movements. Use these tips to adjust the sensitivity

  • Turn the sensitivity dial down one-eighth of a turn at a time until the lights remain off
  • Use black electrician tape to block off the lens area that is detecting unwanted motion

When you install a motion detector for your outdoor lights, consider using an LED bulb. These bulbs operate well in the cold and are energy efficient. Remember to ask an Expert for help if you have additional questions about the installation process.

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