Distribution has been disrupted “across the country”, Fullard Gwasira, a spokesman for the power utility said.
The company is trying to restore units at the Kariba hydropower and Hwange thermal-power facilities.
“It isn’t clear how long it’ll take to rectify the faults, but we’re working as fast as we possibly can,” said Gwasira.
Parts of the capital haven’t had electricity for two days.
Zimbabwe produces an average of 1,300 megawatts of power compared with peak demand of 2,200 megawatts, resulting in daily rationing and blackouts that have paralyzed mines and industry, according to the Confederation of Zimbabwe Industries.
Ben Bvumaranda, who owns a luxury furniture-making business in Harare’s eastern Msasa industrial area, said he had sent workers home.
“I’ll call them back when power is restored, but I have had no electricity since last night and calls to Zesa’s fault desk are constantly engaged, so we have no idea how long this will be,” he said.
“All we know is it is costing money.”