The second power outage in one day left more than 4,400 San Francisco Pacific Gas & Electric customers without power Friday night.

PG&E spokesman J.D. Guidi said the outage, which began at 8:28 p.m., originally affected 5,050 customers near Noe Valley.

Two PG&E workers arrived in the affected area at about 8:50 p.m., Guidi said, and were working to fully restore service but had yet to identify the source of the outage.

On Friday morning, an outage reported at 12:39 a.m. knocked out power to nearly 6,700 Hayes Valley PG&E customers. That outage was caused by an underground equipment failure, Guidi said Friday morning.

Those customers had their power fully restored by 6:30 a.m., he said.

When asked whether the two incidents were related, Guidi said that, without information about the cause of the latest outage, he could not speculate on any possibly connections.