Observatory and surrounding areas are still in the dark, following an underground fire on Thursday evening.
City Power said the Johannesburg Emergency Services (EMS) has successfully extinguished the underground fire.
The Observatory and Bellevue substations had to be isolated by City Power on Thursday night after receiving reports of the flames.
Isaac Mangena, Spokesperson of City Power, said technical teams will begin assessing the extent of the damage, as soon as the smoke in the tunnels dies down.
Areas affected are Bellevue, BezValley, Bruma, Cyrildene, Kensington, Houghton Estate, Observatory and surrounding areas.
“It’s still unclear at this stage what sparked the fire, but we are deeply worried about repeated cases of fire in our underground tunnels, most of which are caused by acts of theft and vandalism.”