Why Do My Lights Keep Flickering or Blinking?

July 13, 2018

An occasional light flicker in your home is normal. But if you’ve noticed flickering that didn’t happen before, has started happening regularly, and/or is severe, you need to investigate.

Flickering or blinking lights are usually caused by one of four things:

  • Problem with the bulb (not in tight enough, wrong bulb type for dimmer switch)
  • Loose light plug
  • Faulty light or fixture switch
  • Appliance pulling large amounts of current on startup, causing a voltage drop

Or there may be a bigger electrical issue:

  • Sensory overload on a circuit
  • Voltage fluctuations
  • Loose or outdated wiring
  • Problem with the electric utility service
  • Problem with the meter box or main service cable connection

Let’s take a look at each.

Problem with the Bulb

If the flickering is only in one light, first check to make sure the bulb is screwed in tightly. This may seem obvious, but bulbs can come loose over time and lose their connection with the socket. Try tightening the bulb. If that doesn’t work, you may try replacing it.

The flickering may be related to the type of bulb.

  • Do you have fluorescent bulbs? They have a tendency to flicker, especially as they power up or in cold temperatures. If your fluorescent lights flicker occasionally, it’s probably nothing to worry about.
  • Do you have LED bulbs? The most common cause of flickering has to do with dimmer switches. Dimmers are made to handle higher electrical loads and don’t always play well with lower-voltage LEDs.

More about dimmer switches…they don’t work well with most fluorescent and non-dimmable CFL bulbs. To avoid flickering, make sure you use only dimmable bulbs that are compatible with your switch.

Loose Light Plug

Is the flickering problem only with one lamp? The problem could be a loose connection between the plug and outlet. Check to see if the lamp’s plug is firmly in the wall socket. If not, try unplugging it, adjusting the metal prongs, and plugging back in again.

Faulty Light or Fixture Switch

A poor connection between the light or fixture switch and the bulb can cause flickering. Try gently wiggling the switch to see if this causes a flicker. If it does, you’ve found the problem. If your light is already flickering, try toggling the switch on and off and see if this fixes the problem. If it does, the switch is the culprit and should be replaced.

Overloaded Circuit

Have you noticed that the lights start flickering, blinking or dimming when a major electrical appliance (like your air conditioner or washing machine) comes on? Your problem may be an overloaded circuit—meaning that these appliances are pulling more electrical current than the circuit can handle.

  • If the flickering is infrequent, minor and only happens briefly right when the appliance comes on, this may not be a concern. Large electrical appliances draw more current as they start up. This causes a voltage drop, which results in the flickering or dimming lights. Even in a well-designed electrical system, with large loads on their own circuits, some minor flickering of this nature can happen. The better the system design, the less noticeable it will be.
  • If the flickering happens consistently, is severe and/or doesn’t stop right away, there is a problem. The issue might be with the appliance itself. Bearing failure, for example, will cause the motor to pull more current as it struggles to start. Or, there may be too much sensory overload on the same circuit. Call an electrician to find the source of the problem.

Voltage Fluctuation

Fluctuating voltage is another cause of flickering lights. Signs include:

  • Lights consistently flicker when you turn on a large appliance
  • Flickering continues after the appliance has stopped running
  • Unpredictable, unexpected dimming
  • Lights burn out frequently

Slight fluctuations are normal, but your home should always register between 115 and 125 volts. You can check your home’s voltage using a device called a voltmeter. If your readings average above 125 volts, you’ve found the underlying cause of your flickering lights. An electrician can find the best solution to resolve your voltage problem.

Electrical Usage from Neighbors

Your home likely shares a transformer with surrounding homes, so their loads impact your electrical supply. A neighbor’s heavy electrical usage could be behind your flickering lights. If the problem doesn’t resolve, an electrician is your best resource for locating the issue.

If lights are flickering at your neighbors’ houses, too, there might be a problem with the electric utility service itself. Report it for repair.

Loose Wiring Connections

Loose wiring can not only cause flickering lights, but is a leading cause of house fires. The problem may be systemic or found in only one location, but is always dangerous. Old and outdated wiring, breakers, switches and connectors are always cause for concern. Outdated wiring is another top cause of house fires.

Loose connections in an outlet, light or switch box can cause arcing, where electrical current “jumps” over gaps in the connection. This is a major cause of electrical fires. If a circuit connection is loose, it creates a high resistance point, which in turn creates dangerous point heating. A single loose connection can endanger your entire system.

If you’ve noticed an increase in flickering but you haven’t made any changes to your electrical system, loose wiring could be to blame. There are any number of potential problem areas: a switch failure, loose fixture wiring, worn connectors in the breaker box, or loose service conductors in the main electrical panel. Contact an electrician ASAP if you suspect loose wiring or haven’t found another cause for your flickering lights.

If the flickering is in only one fixture, you can check it for loose wiring. You must shut off the light at the circuit breaker before removing the fixture. (If you’re not absolutely sure how to do this, do not attempt!) If the fixture appears loose or insecure, call an electrician ASAP to fix. If not, and you haven’t found another cause for the flickering, call an electrician. Wiring problems are not something to ignore.

Lights Are Flickering Throughout the House

This likely means there’s a problem at the meter box connection or main service cable connection. Call an electrician ASAP. These are high capacity wires and could be a fire hazard.

Bottom line: You should never ignore a problem with flickering lights. It may be a simple fix, like a new bulb or fixture switch, but can be a symptom of a larger electrical problem.

If you’re in the Wichita area, Reddi electricians can help with your flickering lights. Give us a call today at (316) 771-9699.

Resources found on our website are provided as general guidelines, and Reddi Industries does not assume any liability resulting from the provided information.