About 450 businesses and homes in the Kaka'ako area were without power for about an hour yesterday afternoon, including at least one traffic signal on Kapi'olani Boulevard and South Street.

The cause for the blackout is still being investigated, said Hawaiian Electric Co. spokesman Peter Rosegg.

HECO workers yesterday afternoon were inspecting the main conductor that sends power to the area.

The conductor is partially overhead and underground, so it may take some time to inspect and possibly a couple days to find out what the exact problem was, Rosegg said.

The power outage — which covered areas in Kaka'ako near Alapa'i Street, Kapi'olani Boulevard and Ward Avenue — was reported at about 1:44 p.m. Power was restored by about 2:35 p.m.

Honolulu police said they received reports of an explosion near Ward Avenue and Waimanu Street around the time the power outage began.

"We have no information or anything that would indicate there was any kind of a connection to that," Rosegg said.