The power system is still severely constrained, with a high probability of load shedding, Eskom said in a statement on Thursday morning.
Breakdowns in generation units and delays in others returning to service have triggered a shortage of electricity.
"While no load shedding is anticipated at this point, Eskom could be forced to implement Stage 1 or, if necessary, Stage 2 load shedding at short notice should any further breakdowns occur. This is most likely to occur between 17:00 and 22:00 in the evening."
Eskom appealed to the public "to help the country get through these constraints by reducing the usage of electricity".
Breakdowns are currently totalling 14 711MW of capacity, while another 2 220MW is unavailable due to planned maintenance.
On Wednesday night, Stage 1 load shedding returned after a break of just more than a week.
The average age of Eskom power stations is around 40 years, and the utility is struggling to keep these units in operation. Its newly-built Kusile and Medupi power stations have also seen breakdowns - due in part to engineering problems - which contributed to intermittent load shedding.