A problem with the underground electrical cable lines at Makaha Valley Towers has knocked out power to parts of five of the 10 buildings at the 586-unit complex, one of the largest residential condominiums on Oahu.

The outage, which began last evening, cut off elevators, lighting and hot water heaters in the affected buildings, said general manager, Joanna Miranda. Miranda said the outage is confined to the common areas and that all apartments in the affected buildings have electricity.

The condominium's five ocean-side buildings have full power in all areas, she added.

Miranda said engineers are working on the problem now and hope to have electricity restored soon. The trouble is with an underground cable line, she said.

"It's one of our 480 voltage lines that has a problem in it," said Miranda, who quickly added that the problem has nothing to do with Hawaiian Electric Company, which services power to the apartments in the complex.

Because the condominium's backup generator operates off the troubled 480 voltage line, Miranda said that system could not be activated. Portable generators are being brought in as a temporary emergency backup power source, she added.

Meanwhile, people living in the affected areas, including elderly residents, cannot use the elevators.

"We have extra maintenance and our staff coming in and helping them up and down the stairs," said Miranda. "But we should have everything up and running hopefully by this afternoon."