Bryanston and the surrounding areas in Johannesburg are experiencing power outages following an explosion at Brynorth substation, City Power said on Saturday.
A feederboard at Brynorth blew up, damaging equipment, City Power said.
It is currently unclear how long the damage will take to repair.
The affected areas include Bryanston, Morningside, River Club, Douglasdale and surrounding areas.
"Traffic will also be affected, as most parts of William Nicol [Drive] through Bryanston remain off," City Power said.
An update will be given once technicians have determined the extent of the damage, City Power tweeted at 11:11am. Operators were on site at the time.
Photos: City Power Johannesburg (Twitter)