SAN JUAN CAPISTRANO : Unexplained Power Outage Affects 1,460

Power company officials were in the dark about an electrical outage that knocked out service to the entire downtown area for about half an hour Wednesday morning.

The outage cut power to computers and darkened office buildings and traffic signals until service was restored by San Diego Gas & Electric workers shortly before 10:30 a.m.

Power officials and local police said there were no reports of damage or injury. About 100 people called the agency to report the outage, which affected about 1,460 customers.

“There was no apparent damage to the system,” said Tom Larimore, a spokesman for the power company. “Our people haven’t yet been able to find a cause.”

Larimore said some blackouts are caused by large numbers of birds gathering on aboveground power lines.

“It happens fairly often,” he said. “If a lot of them congregate on a wire, then something happens to startle them, the wires start swaying when they take off. If the wires touch, then the circuits cross.”

Crossed power lines can cause an electrical surge to the nearest substation, where circuit breakers close to prevent damage to the power system, Larimore said.

The circuit breakers for the substation serving the downtown area were found to be closed, he added.

The outage affected an area reaching from Oso Road in north San Juan Capistrano to Doheny Road.