Eskom will start to implement stage 2 load shedding from 08:00 on Friday, due to an increase in generation unit breakdowns over the past few days.
The rotational power cuts will last until 22:00 on Friday.
"Breakdowns this week have removed more than 13 500MW of capacity from the system, while planned maintenance stands at 5 000MW of infrastructure. Eskom is working hard to return as many of these generation units to service," it said in a power update.
- FIND | Your load shedding schedule
The power utility has warned that the constrained supply situation may last throughout the weekend, although it has not yet announced whether South Africans will face power cuts.
- Compiled by Jan Cronje