The outage began at about 10:58 a.m. but within eight minutes was restored to all 7,980 customers, said SCE Spokesman Paul Klein.
"It involved one of our substations; multiple circuits were affected," Klein told Patch.
At least one school campus, Vista Murrieta High School, was affected, according to Karen Parris, spokeswoman for the Murrieta Valley Unified School District.
SCE was investigating the incident.
"We don’t know what the cause is as of right now," Klein said, at about 12:30 p.m.