The outage at West Valley College was reported around 7:30 a.m. and caused students and faculty to be turned away from the campus, located at 14000 Fruitvale Ave., according to district spokesman Peter Anning.
After not being able to figure out what caused the outage by noontime, district officials decided to cancel classes for the day, Anning said.
Power had not been restored on campus as of 12:15 p.m., but Anning said crews will be working the rest of the day to restore power and are planning to be open when students return Friday.
There are typically around 1,600 students who would be normally be attending classes at the school on a Thursday, but none are allowed on campus today while crews determine the cause of the outage, he said. All non-essential employees on campus have also been sent home for the day.
PG&E spokeswoman Brandi Ehlers said the problem is on the school's end of the service, and that the power is working fine in the area.
Anning said construction was being done on campus that may have been responsible for the outage.
Students are advised to check the school's website, www.westvalley.edu, for the latest information on the closure of the campus.