'Mud' on power lines causes outages for 5,000

(05-26) 15:17 PDT -- Wet weather combined with an accumulation of dust caused a series of power outages Sunday morning that left as many as 5,000 PG&E customers in San Francisco and on the Peninsula without electricity Sunday morning.

The outages started around 5 a.m. when a heavy drizzle mixed with a build up of dust to form a "mud-like mixture" on power lines, said PG&E spokesman J.D. Guidi. That mixture, which can conduct electricity on the outside of the power lines, caused several electrical shorts and minor power pole fires, he said.

At the height of the outages, about 3,000 customers were with power, primarily in the Richmond and Excelsior districts, Guidi said. In addition, power was out for as many as 2,000 customers in South San Francisco.

PG&E brought in extra crews to the affected areas. By mid-afternoon, about 1,000 customers in San Francisco and 700 in South San Francisco were still without power, he said.