City Power spokesperson Louis Pieterse said the substation located in Prospect tripped, causing various other smaller substations which it supplies to lose power.

"It's a 'downstream effect', Prospect is a substation that imports the electricity from Eskom — this results in various grids in Johannesburg losing power," he said.

What the public thinks

"There are about 30 areas without power, including the areas in the CBD, Gresswold, Kensington, Bellevue, Mondeor, Glenvista, Rosettenville and Booysens."

Johannesburg metro police spokesperson Wayne Minnaar said traffic lights in the Johannesburg CBD were not working, causing major disruptions to people travelling to work.

Bree, Sauer and Rissik streets were among those affected, as well as Houghton, Parktown, Orange Grove and most of the inner city.

"Metro police officers would be sent to intersections to direct traffic," Minnaar said.

Pieterse said the substation's tripping could have been caused by theft or vandalism — which would interfere or damage circuits, or there could be a transmission line problem.

Technicians were on the scene trying to rectify the problem.

"We should expect power back before midday," Pieterse said.

Sapa

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