squirrel-line.jpg (Oregon Live) A squirrel reaching from a live wire to a grounded transformer at the Washington County Fair Complex caused a connection that wasn’t supposed to be, electrocuting the bushy tailed critter and knocking out power to 110 of Portland General Electric’s Hillsboro customers for about two hours Tuesday. The squirrel did not survive, said PGE spokesperson Steve Corson. The outage occurred at about 12:43 p.m. Crews replaced a wire and a blown fuse on the transformer, restoring power to all customers by 2:45 p.m. Other than weather, squirrels are the most common cause of power interruption across the nation, including large outages in Portland in December 2005, and in Salem in October 2004, Corson said.

Mystech: I point your attention to the following: “A Google search of ‘squirrels causing power outages’ found 198,000 articles, newscasts and other postings” and “sparked blog theories of a squirrel terrorist conspiracy”. This is a concerted, unrelenting effort and I’m not alone in this belief. Now, can I leverage this fear and paranoia into a political campaign? Nah, no one would ever fall for something like that. :-)

Power companies spend a significant amount of time and resources to prevent squirrels from gaining access to electrical transformers, substations and power lines. Although the available deterrents can be expensive, the cost pales in comparison with the cost of the damage done, he said.

“We do quite a lot of work to minimize this,” Corson said.

A squirrel might chew into a live line, for instance. Like most rodents, a squirrel’s teeth grow about 6 to 10 inches a year, and it must chew to keep them in check.

Or the squirrel might come into contact with a piece of equipment while touching an energized line with another part of its body, as in Tuesday’s case. The result is usually a blown fuse, but sometimes the damage from the resulting surge is great, shorting out people’s appliances and/or causing widespread outages.

Birds, too, sometimes create these unwanted connections, but “birds aren’t as reachy,” Corson said.

The furry rodents are difficult to discourage. They often use the power lines as an easy, direct means of transportation. All animals have learned behavior and, like people, will follow the path of least resistance, said Susan Barnes, a biologist with the Oregon Department of Fish and Wildlife. A squirrel’s natural flexibility and athleticism often leads to its untimely demise, Corson said.

PGE uses plastic fences with a mild electric current around transformers to give curious squirrels a mild shock, said spokesperson Mark Fryburg. Other companies sell rings of hard plastic to place around the base of power poles and at the end of power lines. When the squirrel tries to grab the objects, they spin, throwing the squirrel off. Acrobatic types who get past the first defense find slippery plastic casings that encircle the lines themselves, preventing good traction.

It isn’t difficult to find more instances of squirrel-caused power outages. A Google search of “squirrels causing power outages” found 198,000 articles, newscasts and other postings. On Aug. 14, reports of three separate incidents that caused outages to more than 50,000 power customers sparked blog theories of a squirrel terrorist conspiracy.

Becuase of squirrel prevention efforts, animal-caused outages dropped from 25 percent of the total in 2002 to 17 percent in 2005, Fryburg said.

As human encroachment on nature continues, problems with wildlife are likely to escalate, Barnes said. About a thousand miles of high-voltage transmission lines are added each year in the U.S., Corson said.