Eskom will implement Stage 1 load shedding on Saturday from 09:00 to 23:00.
It said in a statement on Friday evening that the system remained under severe pressure with several generation units being out of service.
Eskom announced on Friday that it had suffered a major setback, after losing three units at the Medupi power station in Limpopo due to coal and ash handling issues.
This, after the breakdown of a conveyor belt that feeds coal to the power station.