Load-shedding is back from 10pm on Tuesday.
Eskom has announced that it would implement stage 2 rolling blackouts overnight until 5am on Wednesday.
The power utility said the cuts were necessary to replenish its emergency reserves.
“This load-shedding is necessary to preserve and replenish the emergency generation reserves and to maximise the capacity available during the day.
“The power generation system is still severely constrained due to high-generation unit breakdowns during the past two days, as well as the delayed return to service of some units out on planned maintenance,” it said.
Eskom said it had 4,858MW out on planned maintenance, while another 14,375MW of capacity was unavailable because of breakdowns and delays.
The power supplier said it expected the units that were out of service to be restored by Wednesday.
“The system will continue to be constrained, with the risk of load-shedding remaining elevated,” it added, calling on the public to use electricity sparingly.