Power utility Eskom will implement Stage 2 load-shedding from 16:00 on November 2 to 05:00 on November 3.
This follows after a unit at the Kusile power station tripped on Tuesday afternoon. A unit each at the Matimba and Arnot power stations had also failed to return to service.
Eskom warns that the power constraints are likely to persist for the remainder of the week and that it may have to extend load-shedding.