At least 30,000 people were without power for several hours on Thursday evening in Long Beach after a massive underground vault explosion, according to Southern California Edison.
By 11 p.m., SCE officials announced that all but 400 customers had their power restored.
The outage was first reported around 4:14 p.m. in the area of 10th Street and Pine Avenue, according to SCE spokesman Robert Villegas.
At least three substations had to be shut down in order to investigate the issue, Villegas said.
No estimate was given on when full power would be restored.
An overnight shelter was set up at the Cesar Chavez Park Community Center.