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How To Wire A Motion Sensor To An Existing Light


As a licensed electrician, I have seen firsthand the benefits of motion sensor lights and have helped countless clients in the East Providence, Rhode Island area successfully install them. At B&K Electric, our family-owned and operated business has been serving the residents of Rhode Island for over seventeen years. We specialize in electrical repair, panel maintenance, and installation, making us the ideal go-to electrician for your home or business in the Warwick and greater Providence area.

In this article, I will provide step-by-step instructions on how to wire a motion sensor to an existing light. Whether you are a homeowner looking to increase the security of your property or simply want to save on electricity bills, this guide will help you successfully install a motion sensor without the need for professional help.

Before diving into the wiring process, it is important to first understand the types of motion sensors available in the market. There are two main types: hardwired and wireless. Hardwired motion sensors require a physical connection to the house’s electrical wiring, while wireless ones use radio frequency signals to communicate with an existing light system. For the purpose of this article, we will focus on the wiring process for the hardwired motion sensor.

As with any electrical project, safety should be your top priority. Make sure to always turn off the power to the area you will be working on at the circuit breaker before starting the installation process. It is also recommended to use a non-contact voltage tester to ensure that the power is completely shut off before proceeding.

Now, let’s get into the wiring process. Here are the steps to follow when wiring a motion sensor to an existing light:

Step 1: Choose the location for the motion sensor

The first step is to determine where you want to place the motion sensor. Ideally, it should be installed in a high traffic area or near a main entrance to the house. This will ensure that it detects motion efficiently and effectively.

Step 2: Turn off the power

As mentioned earlier, ensure that the power to the area is turned off before beginning the installation process.

Step 3: Remove the existing light fixture

Carefully remove the existing light fixture from the wall or ceiling to expose the electrical wiring and junction box behind it. You may need to use a screwdriver to remove any screws holding the fixture in place.

Step 4: Install the mounting bracket for the motion sensor

If your motion sensor came with a mounting bracket, attach it to the junction box using the provided screws. If it did not come with a bracket, you can skip this step and proceed to the next one.

Step 5: Connect the wires

Inside the junction box, there should be a black, white, and copper wire. These correspond with the black (hot), white (neutral), and green (ground) wires of the motion sensor. Use wire nuts to connect the black wires together, the white wires together, and the copper wires together.

Step 6: Connect the motion sensor to the mounting bracket

If your motion sensor has a mounting bracket, attach it to the bracket using the provided screws. If it does not have a bracket, simply use the screws provided to attach the motion sensor directly to the junction box.

Step 7: Test the installation

Once all the wires are connected and the motion sensor is securely in place, it’s time to test the installation. Turn the power back on and flip the switch for the light connected to the motion sensor. The light should turn on. If it does not, turn off the power again and recheck all the connections.

Step 8: Adjust the settings

Most motion sensors have adjustable settings for sensitivity, time delays, and distance. Refer to the manufacturer’s instructions to adjust these settings according to your personal preferences and the layout of your home.

Step 9: Mount the light fixture back in place

Once everything is connected and tested, mount the light fixture back in place and turn the power back on. Your motion sensor is now successfully installed and ready to use.

Wiring a motion sensor to an existing light may seem daunting at first, but with the proper guidance and safety precautions, it can be a simple and fulfilling DIY project. By following the steps outlined in this article, you can save time and money by installing a motion sensor without the need for professional help.

In summary, motion sensors are a practical and effective way to enhance the security and energy efficiency of your home. With a little bit of knowledge and the right tools, you can easily wire a motion sensor to an existing light and enjoy its benefits. At B&K Electric, our team of experienced and licensed electricians is always ready to assist our clients with any electrical needs. Contact us today for all your electrical repair, maintenance, and installation needs.


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hardwired motion sensor,

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