An underground equipment failure caused a blackout Friday that initially affected 1,400 homes and businesses, including Santa Rosa Memorial Hospital, according to PG&E.

The hospital, which includes the region's trauma center, was operating on its own backup generators Friday night, PG&E spokeswoman Jana Morris said.

The equipment failure occurred close to the hospital, thwarting the utility's attempt to reroute power to the hospital, she said.

Repairs to the failed equipment should be completed by 9 to 10 a.m. today, Morris said.

PG&E was attempting to bring in generators to support the hospital's backup system, she said.

A Memorial Hospital spokeswoman could not be reached for comment Friday night.

At 8:30 p.m., 164 customers were still without power, Morris said.

The outage affected an area from Highway 12 to Santa Rosa Creek and from Santa Rosa Avenue to Yulupa Avenue.

Memorial Hospital was hit by four power outages in 24 hours on Nov. 15 and 16.