Power utility Eskom announced on Thursday afternoon that it would implement Stage 3 load-shedding from 08:00 to 22:00 on Friday.
Load-shedding moved from Stage 2 to Stage 4 on Wednesday afternoon.
Eskom on Thursday said that, although its teams had successfully returned a generation unit each at the Tutuka, Matla, Majuba and Camden power stations, two other units had suffered breakdowns.
Unplanned breakdowns amount to 11 185 MW of capacity, adding to the 5 040 MW currently out on planned maintenance," the utility said.
It noted that load-shedding would also continue into the weekend in order to replenish the emergency generation reserves.