Load shedding could be implemented should there be any breakdown at its plants, said the state-run parastatal, the main electricity supplier in the country.
However, the utility assured that there wouldn't be load shedding on Sunday after some power generating units resumed operation.
South Africa has been hit by four straight days of blackouts which dealt a heavy blow to economic activities and seriously affected people's lives.
To supplement capacity, embattled Eskom resorted to emergency diesel and water reserves on Saturday.
Efforts to repair a conveyor belt that malfunctioned and resulted in load shedding at Medupi power station in Limpopo Province were going well, the utility said.
Meanwhile, a petition to save Eskom before it takes the entire country down with it, has been signed by almost 70,000 people.
The opposition Democratic Alliance (DA), which launched the petition last week, said there are still 30,092 signatures needed to reach 100,000.
"When the lights go out, people stop working, business shuts down and our country slides even further backwards," the party said.
South Africa has suffered from power insufficiency since 2008. Power blackouts have become more common in recent years.
Eskom, haunted by poor management and alleged corruption, has been accused of using rolling blackouts to blackmail the government into repaying its heavy debt, but the utility has denied the accusation.
Experts estimate that each stage of rolling blackouts costs the country one billion rand (about 68 million U.S. dollars) per day.