Eskom said stage 2 load-shedding would be implemented on Thursday afternoon.
The power utility said the stage 2 rotational power cuts would be in place from 3pm to 11pm. This after stage 1 load-shedding had been in place from Thursday morning.
Earlier, Eskom had said the shedding was due to plant breakdowns, which had resulted in an imbalance between supply and demand. Residents and businesses have been urged to use electricity sparingly.
"Please visit the websites of your electricity providers for a list of which areas will be affected," Eskom said.