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How To Wire A Motion Sensor To An Existing Light


Are you tired of coming home to a dark house and fumbling for the light switch? Or maybe you’re worried about leaving your outdoor lights on all night and wasting energy? Luckily, there is a simple solution to both these problems – installing a motion sensor for your existing light. And for residents of Providence, Rhode Island, B&K Electric is the go-to electrician for this project.

With over seventeen years of experience in electrical repair, panel maintenance, and installation, B&K Electric is a family-owned and operated business rooted in community and customer service. Based in Warwick, RI, our team of licensed electricians proudly serves the residents of Cranston, Warwick, and all of Rhode Island. And today, we will be sharing with you our expertise on how to wire a motion sensor to an existing light.

First, let’s understand what a motion sensor is and how it works. A motion sensor, also known as a motion detector or occupant sensor, is a device that detects movement in its surrounding area and responds by turning on a light. There are two types of motion sensors commonly used – passive infrared (PIR) and ultrasonic.

A PIR sensor detects changes in infrared radiation emitted by people or objects within its field of view. When a person or object moves, their body heat causes a variance in the infrared radiation, triggering the sensor to send a signal to the light to turn on. On the other hand, an ultrasonic sensor uses high-frequency sound waves to detect motion. When the sound waves are disrupted by movement, the sensor signals the light to turn on.

Now, let’s dive into the steps of wiring a motion sensor to an existing light.

Step 1: Gather the Necessary Tools and Materials

Before starting the project, make sure you have all the necessary tools and materials on hand. You will need a screwdriver, pliers, wire strippers, electrical tape, wire connectors, and a motion sensor kit. The kit typically includes the sensor, mounting bracket, mounting screws, and wire nuts.

Step 2: Turn Off the Power

For safety reasons, always turn off the power to the light you will be working on before beginning the installation. You can do this by locating the circuit breaker for that particular light and turning it off.

Step 3: Find the Right Location for the Sensor

Next, determine the ideal location for the sensor. Keep in mind that it should be within the sensor’s field of view and at a height of 6-10 feet. Make sure there are no obstructions or objects that can block the sensor’s view. For outdoor lights, choose a location protected from harsh weather conditions.

Step 4: Install the Mounting Bracket

Place the mounting bracket on the chosen location and mark the screw holes with a pencil. Drill the holes and insert the screws, leaving them slightly loose so you can adjust the angle of the sensor later.

Step 5: Connect the Wires

Now it’s time to connect the new wires from the motion sensor kit to the existing light wires. First, strip the ends of the motion sensor wires and the existing light’s wires. Then, connect the black wire of the motion sensor to the black wire of the light using a wire nut. Repeat this step with the white wires and the green or bare wires, connecting them to their respective colors. Finally, cover the wire connections with electrical tape for added safety.

Step 6: Mount the Sensor and Secure the Wires

Mount the sensor onto the bracket and secure it with the mounting screws. Tuck any exposed wires into the wall or ceiling and use a wire connector to secure them. Make sure the connections are tight and free from any exposed wires.

Step 7: Test the Sensor

Once everything is installed and connected correctly, turn the power back on and test the sensor. Move within its field of view, and the light should turn on. If it doesn’t, check the connections and adjust the sensor’s angle if needed.

Step 8: Adjust the Sensor Settings (Optional)

Most motion sensors come with adjustable settings, such as the sensitivity, the length of time the light stays on, and the light level at which it will activate. If your sensor has these settings, you can adjust them according to your preference.

Wiring a motion sensor to an existing light is a simple project that can enhance your home’s safety, security, and energy efficiency. With B&K Electric’s expertise and the right tools and materials, this installation can be completed in no time. So why wait? Contact B&K Electric now to get your motion sensor installed and enjoy the convenience and peace of mind it brings.


Motion Sensor,

Existing Light,

Electrical Repair