Why do my lights blink?

Posted on Mar 22 2018 in Fulton County REMC

Greg Bitterling

Every once in a while, I get the loaded question: “Why do my lights blink?” This is never an easy question to answer.

In my nearly 20 years at Fulton County REMC, I have probably seen at least 100 different reasons for blinking lights. Many times they only blink once in a while and only when the conditions are just right. It can be very hard to find a problem that is never happening while you are looking for it!

Sometimes lights are supposed to blink. The power grid is subject to certain short-term losses of power. These could be a lightning strike, an automobile hitting a pole, or an animal or tree branch coming into contact with an energized power line or anything that may temporarily short out our 900+ miles of line. When lights blink, it is an indication that the cooperative’s equipment is operating properly.

If a fault or short circuit happens on a power line, a device called an oil circuit recloser (OCR) opens to stop it. Then, it quickly closes back in. The OCR is essentially a breaker functioning much like a circuit breaker in the electrical panel in your home. It permits power to continue flowing through the line with only a brief interruption of service — rather than causing an extended power outage. If the short circuit continues or does not clear itself, the OCR will operate or “trip” three times before eventually stopping the flow of electricity and causing a power outage.

Because we have over 900 miles of line exposed to weather, animals, trees and anything else that may short the line, these blinks are necessary. If we did not use OCRs every time anything shorted the line, it would become an outage. I think we all would prefer a momentary blink over an outage that could last for hours!

The lines that feed power to our substations also have OCRs. Because of this, sometimes our whole substation will blink, and we have no control over it. This kind of blink will affect hundreds of members.
Sometimes, a loose connector at our transformer or where the wire connects to your meter can be the problem. Remember: We did not install your meter base. Our members are given a meter base, and they hire an electrician or install it themselves. Then, we come and set the meter in the base. A loose connection anywhere on the wire from the transformer to the blinking light can be the cause. Even the lightbulb itself can be the problem.

A broken filament in an incandescent bulb can cause it to blink. Sometimes it is as simple as a loose bulb or a bad socket that the bulb screws into. I have even seen new LED bulbs blink. Some of the cheaply built LED bulbs have a capacitor in them that is rated at about 105 F. If this bulb is installed in an enclosed light fixture, it may get hotter than 105 F, and the bulb goes out. When the bulb goes out, the temperature cools. The capacitor comes back on, and the bulb lights back up.

In some cases, we will see some bulbs dim, and other bulbs become brighter in the home. This is from a loose neutral connection. The neutral wire is the wire that balances the load in your home. All homes in the U.S. are wired with two legs of 120 volts coming into the home. Our larger appliances may need 240 volts. In that case, both legs are used to power the appliance.

Smaller appliances like lights use 120 volts. In this case, the neutral wire is the return path and balances the load. If the neutral wire is loose, the load will not be balanced, and some lights will get higher voltage (making them brighter), and some will get lower voltage (making them dimmer.)

A bad cord on an appliance or even the outlet it is plugged into could be bad. This will cause the plug to be loose and not make a good connection.
Overloaded breakers will heat up and cool down causing all kinds of problems. Sometimes the buss bar the breaker is attached to can get damaged. Or maybe your service is overloaded causing a meter connection to overheat.

The list can go on and on. But we can only narrow down the cause of these kinds of blinks by asking a lot of questions, including:

  • How often?
  • What time of day?
  • Did your neighbors’ lights blink?
  • Were any appliances running when the lights blinked?

The more details you can give us, the better chance we have of finding the problem.

If you do have problems with blinking lights and haven’t been able to track down the problem or just want to protect your equipment, consider purchasing an uninterruptible power supply (UPS) for your computers and other sensitive electronic equipment. These power supplies often have surge protection built in. Unlike a surge protector, a UPS will protect against surges and drops in the power supply.

Greg Bitterling
Member Services Manager
and Energy Advisor at
Fulton County REMC