Story highlights Only 3,000 still without power

Cable cars were halted and people were stranded in elevators

(CNN) The lights are back on in San Francisco.

About 90,000 people were without power there for much of Friday after a circuit breaker failed at a substation, igniting insulation and causing a fire, investigators said.

The outage affected mostly the northern and central neighborhoods, including Pacific Heights, the Presidio, the Financial District and Fisherman's Wharf.

Service was restored to all but 3,000 by 8 p.m. ET, said Pacific Gas & Electric spokeswoman Nicole Liebelt.

PG&E said power should be fully restored later Friday evening.