Cape Town - Eskom has announced that Stage 1 load shedding will be implemented from 17:00 until 22:00 on Friday.
"Any unexpected changes on the constrained power system could lead to a stage change at short notice. We apologise for the inconvenience," it said on Twitter.
"The electricity system remains significantly constrained today and leading into the weekend, as well as next week as demand surpasses available supply," Eskom said in a statement.
Load shedding comes a week after Eskom plunged Soweto into more than 10 hours of power cuts.
Eskom acting CEO Brian Molefe apologised to the residents of Soweto for the inconvenience caused by the prolonged power outage last Friday.
The apology came after a protest march against power cuts in Soweto ended peacefully on Thursday afternoon, despite an earlier threat that a group would try to hijack proceedings.
The risk of a total blackout is lower than it was a decade ago, according to the man behind Eskom’s load shedding operations.
Eskom’s general manager of the national electricity system operator, Robbie van Heerden, said the transmission network has been strengthened, and there is heightened awareness and contingency plans in place to avoid a blackout scenario.
Plan your load shedding times: GridWatch