How To Troubleshoot An Electrical Light Fixture

How To Troubleshoot An Electrical Light Fixture
By Dave Donahue

Basic Light powered by a single pole light switch
Basic Light powered by a single pole light switch

This blog is designed to help anyone troubleshoot a light that is not working. Unfortunately at times, lightbulbs may burn out or in more difficult situations the lighting circuit may not be getting power at all. There are a number of reasons this can happen. Short circuits can cause the breaker at the panel to ‘trip’, or shut off. When this happens the possibility of a break in the wire or a loose wire at the fixture may be the root cause. Breaks in the wire or in the actual wire covering (sheathing) may cause the light to flicker on or off or trip the breaker. This means that the wire supplying power to the fixture itself may be coming in contact with metal inside the walls which conceal the wire. Normally light fixtures are wired using 14/2 NMB (or non-metallic, high temperature) wire.

To troubleshoot a faulty light fixture, first you will need to open up the switch which is turning the light on and off. You will also need to unscrew the fixture and gain access to the junction box which is feeding the light with power. Inside this junction box you should see three wires. One is a ground wire (green), a white wire (neutral) and a black or red wire.(hot) These wires should be connected to the fixture from the junction box. They may be “tailed out’ meaning the wires are connected to other wires inside the box and a wirenut will connect the wires in the junction box which may be supply the light you are working on. The tail is what is supplying power to the fixture you are troubleshooting.

Once you have determined these are connected, go to the switch and using an Ohm meter connect the two wires which are running from the switch to the light. This will be your hot and neutral. If the meter rings then you have continuity. If it doesn’t then you more than likely have a break in the wire and the wire should be replaced. If you are in fact ringing continuity then the problem may lie in the connections between the switch and the fixture. Make sure your wiring is correct. In this case, the green wire(ground) should be attached to the green screw on the switch and the black or red wire should be attached to the brass screw on the switch. Once replacing the fixture and light make sure you have seated the switch correctly in the switch (handybox) and that the terminals are not touching bare metal against the box. This in itself is a common reason many short circuits occur. Once you have wired this correctly go back to the fixture and make sure this is also wired properly.

Single Pole Light Switch

Picture of A Single Pole Lighting  Switch
Picture of A Single Pole Lighting Switch

For a basic understanding of how a single pole light switch is wired, see here. The above link shows you an easy step by step format for wiring up a single pole lighting circuit. Troubleshooting a light fixture which is not working may seem like a daunting task but it is not as complicated as it may seem.  Swartz Electric, a Colorado based electrical company specializes in lighting, receptacle, panel work and more. Last but not least always shut off all power before beginning any repair or installation! If you are not comfortable working on DIY electrical projects yourself, contact Swartz Electric for all your electrical home improvement needs.

Swartz Electric is Colorado Springs highest rated Electrical Contractor and is licensed and insured to perform electrical work throughout the entire State of Colorado. Please see our website for our licenses, insurance, and links to reviews and testimonials. In addition, Swartz Electric provides a 2 year material warranty and a lifetime workmanship warranty.

Swartz Electric – Your Colorado Springs Electrician performs electrical work throughout Colorado Springs, Monument, Black Forest, Fountain, Falcon, Woodland Park, and everywhere inbetween. We are the electricians in Colorado Springs to solve your electrical problems and meet your electrical requirements.

Call, e-mail, visit our website, or stop by our office today, and allow Swartz Electric to serve YOU.

This is an original article written by Dave Donahue for Swartz Electric. This article may not be copied whole or in part without the express permission of Swartz Electric, LLC.

© Copyright 2013. All rights reserved.

 How To Troubleshoot An Electrical Light Fixture

1 Comment

  • Joshua Rodenburg, June 23, 2022

    Thank you for the excellent description on how to troubleshoot an electrical light fixture…my older electrician friend and I recently had to troubleshoot a light fixture in a bathroom, and it was exactly as you described it. I hope others can benefit from your post and all the other excellent posts you post on this page. Thank you for taking the time to educate others on electrical safety and installation.

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