Skip to Content
chevron-left chevron-right chevron-up chevron-right chevron-left arrow-back star phone quote checkbox-checked search wrench info shield play connection mobile coin-dollar spoon-knife ticket pushpin location gift fire feed bubbles home heart calendar price-tag credit-card clock envelop facebook instagram twitter youtube pinterest yelp google reddit linkedin envelope bbb pinterest homeadvisor angies

How To Wire A Motion Sensor To An Existing Light


Maintaining a well-lit home is essential for safety and security, but it can also be costly and wasteful if not done efficiently. This is where motion sensor lights come in. By automatically turning on and off based on movement, they provide both convenience and energy savings. However, if you already have existing lights that you want to upgrade with motion sensors, you may be wondering how to properly wire them. As a licensed electrician in the Downtown Providence, Rhode Island area, we at B&K Electric are here to guide you through the process.

Owned and operated by a local family for over 17 years, B&K Electric takes pride in servicing the residents of Cranston, Warwick, and all of Rhode Island. Our expertise lies in electrical repair, panel maintenance, and installation. As your go-to electrician in the Warwick and greater Providence area, we are committed to providing top-notch customer service and ensuring that your home is equipped with the latest and most efficient electrical systems. So, let’s dive into the steps of wiring a motion sensor to an existing light.

Step 1: Gather Necessary Tools and Materials

Before starting any electrical project, it is crucial to have the necessary tools and materials on hand. For this job, you will need wire strippers, wire nuts, electrical tape, a screwdriver, a voltage tester, and of course, the motion sensor itself. It is also important to ensure that you have the appropriate voltage sensor for the specific wiring in your home. As for materials, you will need 14/2 or 12/2 non-metallic sheathed cable, depending on your existing wiring.

Step 2: Determine the Location and Position

The placement of the motion sensor is key to its effectiveness. You want it to cover a wide area, but also not be triggered by passing cars or animals. Ideally, it should be installed about 6-10 feet above the ground and positioned in a way that covers all potential entry points. If you happen to have multiple existing lights in the same area, you may need multiple motion sensors.

Step 3: Turn off the Power

Safety should always be your number one priority when working with electricity. Therefore, it is crucial to turn off the power to the existing light before beginning the wiring process. Use a voltage tester to ensure that there is no longer any electricity running to the light.

Step 4: Remove the Existing Light

Once you have confirmed that there is no power running to the light, use a screwdriver to remove the light fixture from the wall or ceiling. You may also need to remove the existing wiring from the junction box.

Step 5: Connect the Wires

Using the wire strippers, carefully remove the insulation on the wires that were connected to the original light fixture. You will need to identify the black (hot) wire, the white (neutral) wire, and the bare copper (ground) wire. You will then need to connect the new wires from the motion sensor to these existing wires. The black wire from the motion sensor will connect to the black wire from the electrical box, the white wire from the sensor will connect to the white wire from the box, and the bare copper wire will connect to the green wire from the sensor. You can use wire nuts to securely twist and hold these connections together. Cover the connections with electrical tape for added safety.

Step 6: Mount the New Motion Sensor

Once the wiring is complete, you can now mount the new motion sensor on the wall or ceiling using the provided screws. Make sure it is secured tightly and in the desired position.

Step 7: Test and Adjust the Settings

Before fully installing everything back together, it is important to test the motion sensor and make any necessary adjustments. Follow the manufacturer’s instructions to set the timer and sensitivity level according to your preferences. Test the sensor by walking in front of it to ensure that it properly activates the light.

Step 8: Reinstall the Light Fixture

If everything is working properly, you can now reinstall the light fixture. This may involve reconnecting the wires, mounting the fixture, and attaching the light bulb. Make sure all connections are secure before turning the power back on.

Congratulations, you have successfully wired a motion sensor to an existing light! This simple upgrade can provide not only convenience but also energy and cost savings in the long run. If you encounter any issues or feel unsure about any steps in this process, do not hesitate to contact a licensed electrician for assistance. Safety should always be the top priority when dealing with electrical systems.

Wiring a motion sensor to an existing light is a straightforward process that can greatly enhance the efficiency and convenience of your home lighting. By gathering the necessary tools and materials, determining the ideal location and position, and following the proper steps, you can easily upgrade your existing lights to more efficient and cost-effective ones. As always, make sure to prioritize safety and do not hesitate to seek professional help if needed.


Motion Sensor,


Existing Light.