Southern California Edison said about 21,000 customers in Huntington Beach lost power around 7:45 p.m. when a local substation failed. The exact cause of the outage was under investigation.
It was expected to take until at least 10 p.m. for all power to be restored.
About 15,000 homes in Fontana, which is in San Bernardino County, also lost power for a little over an hour. SCE said that outage was caused by a metallic balloon that landed in a substation.