Electric utilities across the United States have long had to deal with a persistent problem that can knock out power to thousands of customers: squirrels. They routinely chew through wires and insulation and gnaw their way into substations. Storms generally cause the largest and most widespread power outages nationwide, but squirrels are the most frequent cause of outages, even if they are on a smaller scale.
In the Washington, DC area, squirrels are the third most common cause of power outages, behind equipment failure and tree limbs touching power lines. Squirrels are responsible for more outages in the area than storms. Birds and animals were responsible for 9 to 21 percent of unplanned outages in the area in 2013 and 2014.
Utilities are increasing their wildlife protection efforts by lining poles with slippery materials to prevent squirrels from climbing them and by covering as much electrically charged equipment as possible. Even though outages caused by animals have decreased, they still occur.
A family of squirrels chewed through an electrical line in Richmond, Virginia earlier this year and took out power at a high-rise filled with senior citizens for three days. A squirrel took out a substation in the San Francisco Bay area this summer, cutting off power to 45,000 homes. In October, a squirrel blew a transformer in Frederick, Maryland and cut power to almost 2,000 customers. Another squirrel was responsible for a power outage in northwest Washington in November.
Pepco, which provides electricity to the District of Columbia and part of Maryland, invested about $50,000 this year in plastic covers to keep squirrels from climbing on and chewing energized equipment. Nevertheless, about 34,600 of its customers lost power because of animals in the first 11 months of the year. That accounted for about 10 percent of the company’s outages.
Utility companies are continuing to conduct research to find better ways to deal with animals. Squirrels remain the biggest animal threat because of their numbers, intelligence, and persistence.