Understanding Power Surges and Blinks

By Abby Berry

In 2019 alone, squirrels were responsible for more than 1,200 power outages. Photo by Carina Hofmeister.

Have you ever noticed your lights blink during a thunderstorm? Or perhaps you have arrived home to discover the clock blinking on your microwave.

When this happens, you likely experienced a brief disruption to your electric service, which could result from a power surge or blink. While the symptoms of surges and blinks can appear similar, what happens behind the scenes varies between the two.

Power surges are brief overvoltage spikes or disturbances of power waveforms that can damage, degrade or destroy electronic equipment within homes or businesses.

Most electronics are designed to handle small variations in voltage. However, power surges can reach amplitudes of tens of thousands of volts. This can be extremely damaging.

Surges can be caused by internal sources such as HVAC systems with variable frequency drives, or external sources such as lightning and damage to power lines and transformers.

Your electric utility encourages you to install protective devices—such as surge protector power strips—to safeguard your sensitive electronics. If you experience frequent surges in your home or business and you believe the cause is internal, contact a qualified electrician to inspect your electrical system.

Lightning strikes can cause power surges and blinks. Photo by Pat Gaines.

Power blinks are also brief service interruptions typically caused by a fault (short circuit) on a power line or a protective device working in reaction to the fault.

Faults occur for a variety of reasons, including when squirrels, birds or other small animals contact an energized power line; tree branches touch a power line; during lightning and other similar events.

When it comes to power disruptions caused by critters, squirrels reign supreme. In 2019, squirrels were responsible for more than 1,200 outages.

Power blinks also occur when protective devices that act as circuit breakers detect the fault. These brief interruptions are actually good. That means the equipment is working as it should to prevent a prolonged outage.

Regardless of the cause, electric utility crews respond to inspect the damage and make necessary repairs. You can help, too. If you experience repeated disruptions to your electric service, let your utility know.