It can be both annoying and mildly concerning to have an overhead light fixture that flickers. It can also be easy to ignore if the flickering isn't constant but only happens occasionally. In some cases, a flicker can indicate a major or even dangerous problem. The following guide can help you troubleshoot and determine the cause.

Check for external causes first

Sometimes the flicker is completely normal. For example, if the flickering or dimming only occurs when the refrigerator compressor or furnace kicks on, then it is simply a momentary lapse in power when the new device began to draw electricity. It can also be normal for lights to flicker if there is a storm, especially one that involves wind or lightening.

Inspect the bulb

The light bulb can also be a cause of flickering lights. Begin by switching out the bulb to verify that there was no defect in the original bulb causing the flicker. If the new bulb continues to flicker, check that the wattage of the bulb is correct for the fixture rating – sometimes using too high of a bulb watt can lead to flickering. Another common bulb issue is using a CFL bulb with a dimmer fixture, since most CFLs aren't rated for use in a dimming fixture. Switch it out for a dimmable bulb to see if this solves the flickering.

Look for moisture

One somewhat dangerous cause of flickering is moisture in the light fixture. Begin by shutting off the circuit breaker to the light. Next, remove the bulb and check for moisture in the bulb housing. Humid conditions, such as a steamy bathroom, can lead to moisture. Wetness in an overhead fixture could also be indicative of a roof leak, which has lead to wet wiring and a possible short and electrical fire risk. The flickering is caused by the electrical current arcing through the water droplets instead of through the bulb properly, which causes power surges to affect the bulb and lead to flickers. You will need to find the cause of the moisture and repair it before turning the fixture back on. You may also want to have an electrician check the fixture to make sure it isn't damaged.

Consider wiring issues

Wiring issues are the most difficult to diagnose on your own without electrical training. Generally, if the flickering is only affecting the one fixture and there are no issues with other lights, appliances, or outlets on the circuit, the problem likely lies in the wiring for the fixture or in the fixture itself. If other items are also affected, you may have a bad circuit breaker fuse. You may be able to fix the issue by removing the old fuse and replacing it with a new one. Your best option is to call in an electrician to find and repair the problem before it becomes worse or results in a fire.