At about 8:20 a.m., a cable at 20th Street and Telegraph Avenue failed, leaving approximately 400 customers without power, PG&E spokeswoman Tamar Sarkissian said.
As workers attempted to fix the problem, a switch at 21st Street between Telegraph and San Pablo avenues failed at around 9:30 a.m. The switch failure caused an electrical flash, and a few nearby shrubs and a tree briefly caught on fire. Crews quickly controlled the small fire.
The switch failure caused 4,048 customers to lose power.
As of 11:30 a.m., all but five customers had their power restored, Sarkissian said.
The cause of the original cable failure is still under investigation, she said.