San Francisco Hit By Power Outages

Sporadic power outages hit downtown San Francisco on Tuesday, apparently the result of breakers opening in the transmission system at a nearby Pacific Gas & Electric substation.

By Consulting Specifying Engineer Staff July 25, 2007

Sporadic power outages hit downtown San Francisco on Tuesday, apparently the result of breakers opening in the transmission system at a nearby Pacific Gas & Electric substation. Pedestrians on that particular stretch of Mission Street witnessed flames shooting from a manhole, according to a report today from ABC7 news in San Francisco.

The two-hour long power outage affected everything from traffic lights to cable cars, and as many as 50,000 customers lost power, mostly in the financial district.

The incident comes after a number of incidents in recent years have heightened concerns about PG&E equipment.

PG&E announced that the utility had restored power to approximately 40,000 customers after transmission breakers at the company’s Martin Substation opened, causing outages concentrated in San Francisco’s Financial District and the Cow Palace area of the peninsula. The initial event occurred at approximately 1:30 pm, and power was restored to all affected customers by approximately 3:30 pm.

PG&E received reports of an underground explosion on Mission Street between First and Second Streets at approximately 2:30 p.m., the utility reported. Inspection showed that a subsurface transformer failed. However, contrary to preliminary indications, updated reports indicate that this event was not the initiating cause of the larger outages. The company is investigating the cause of the transformer failure.