The Nature of Power Outages

bucket truck on side of the roadOutages often start with a loud boom. The lights go out, and it is suddenly dark and quiet.

When the power goes out unexpectedly, it can be one of many causes: trees and limbs falling on electric lines, vehicles hitting poles, transformers or buried cables failing, squirrels getting into equipment, windstorms, etc.

What all outages have in common is the power does not go out until a system protection device activates.

The most common protection devices are overhead expulsion fuses. These limit the amount of current passing through the device—such as a transformer or underground cable—to a level that protects the equipment from being damaged.

Fuses are on all poles where high-voltage overhead lines connect to transformers, other lines, or underground cables. When fuses blow, they are extremely loud—often heard as a loud boom—and create a bright flash visible for miles.

After seeing the flash and hearing the boom, members often assume the transformer or equipment blew up, but it is just the expulsion fuse doing its job. Actual transformers blowing up is extremely rare.

The leading cause of outages in the PenLight service territory is from trees and limbs falling into overhead power lines. They accounted for just more than half of 2020 outages.

The expulsion fuses protect lines by de-energizing them after a tree limb or a tree has fallen into the lines. This prevents energized lines from laying on the ground and creating a dangerous situation for the public.

Even with protection from expulsion fuses, PenLight needs members to call if they see low or downed lines.

Always assume all lines are energized. Keep yourself, children, pets, and others away from lines and any trees in contact with them. Downed lines and low lines are not safe until PenLight staff can ensure they are de-energized and grounded.

Peninsula Light Operations Department greatly appreciates members reporting outages and providing additional information, such as loud booms, flashes of light, or other information. It may be helpful to our response efforts.