With a constrained power system, Eskom may be forced to implement load shedding, it said on Friday.
"Five generation units were taken off the grid, significantly raising the possible need for load shedding. We urge the public to continue reducing electricity usage to help us avoid load shedding," said Eskom.
Should the need arise; Eskom said it could implement load shedding between 4pm and 10pm.
Two units at the Arnot power station, as well as a unit each at Kendal, Tutuka and Majuba were taken off the grid.
These removed more than 2600 MW of capacity from the system.
The delayed return to service of a generation unit at Duvha power station, has also added significant pressure to the generation system.
Eskom said any additional breakdowns will compromise its ability to supply power to the country.
This constrained supply situation is expected to persist throughout the weekend.
"We request the public to reduce electricity usage between 4pm and 10 pm in order to assist us in preventing the need for load shedding.
"Over the past two evenings the help of the public assisted us in avoiding the need for load shedding. With your help, Eskom can pull through without load shedding," said Eskom.