Hawaiian Electric Co. was looking into the cause of an power failure that left 1,200 customers without power in the downtown area yesterday afternoon.

It began about 12:30 p.m. and electricity was restored about 3 p.m., HECO spokesman Darren Pai said. Power was knocked out to businesses and residents in the 'A'ala and Liliha areas through downtown to near the State Office Tower on Beretania Street, he said.

Five state office buildings were affected, said Russ Saito, state comptroller. He said about 1,100 employees were given the option to leave because "at the time Hawaiian Electric was projecting a restoral time that was late afternoon."