Cause of San Francisco power outage identified as equipment failure

Ed Lee, San Francisco Mayor, reaffirmed that the cause of a power outage Friday morning in the northern part of the U.S. West Coast city was "equipment failure."

Speaking at a 2:00 p.m. press briefing at San Francisco Emergency Operations Center, together with a number other city officials, Lee said he was told that power supply to about 88,000 utility customers was expected to fully restored between 4:00-5:00 p.m. local time.

He was not the first official source trying to narrow down the cause of the outage, as similar events reportedly took place in other U.S. cities on Friday.

San Francisco Police Department (SFPD) twitted that it "understands concerns reg(arding) coincidence of outages..."

However, SFPD notified that Pacific Gas and Electric Company (PG&E) identified that "the fire is due to equipment failure."

PG&E had Barry Anderson, its vice president of electric distribution, to explained at the press briefing what happened at its substation on Larkin Street, about four blocks from the City Hall, that triggered the outage.

It started at about 9:50 a.m., when a circuit breaker in the facility failed, leading to a fire burning the insulation around the breaker.

By 2:00 p.m., power supply to 23,000 customers were restored, said Anderson, who offered an apology to those affected by the incident.

The outage halted the city's iconic cable car operations and stuck 20 elevators with people inside. In addition, as some traffic signals were out, vehicle traffic in the affected downtown areas were significantly slowed. Some businesses were closed due to the incident.

Mayor Lee and officials with the city's first responder services, including Chief Joanne Hayes-White of San Francisco Fire Department, said there were no major injuries reported as a result of the incident. Endit