More than 2,400 homes were left without power Tuesday night in the area around Spring Valley.
SDG&E said on its website the unplanned outage started just before 9:30 p.m. for customers in Spring Valley, La Presa and Rancho San Diego.
The power was shut off "for safety reasons while repairs are being made," the utility's outage map says, though it's unclear what caused the failure.
While SDG&E initially reported power would not be back on until midnight, it was restored just half an hour later.
