File: The outage has apparently been caused by a trip at the Njala substation.
JOHANNESBURG - Eskom continues with rolling blackouts until 11pm.
The embattled power utility has been struggling to keep the lights on since Thursday afternoon.
On Friday, the utility escalated its load-shedding from Stage 2 to Stage 4 and from 11pm Friday night it shifted back to Stage 2.
Increased electricity demand and capacity challenges are being blamed.
Eskom blamed days of "incessant rain" in several parts of the country.
"We are beginning to experience coal-handling problems at a number of our power stations as a result of wet coal," said the statement.
"If the weather persists, we are likely to implement load-shedding through the weekend."
Rolling blackouts in February and March plunged businesses, homes and schools into darkness for hours on end.
Load-shedding resumed again in October when government unveiled plans to restructure the company and orient it towards more renewable sources of energy.
Eskom says load-shedding is required to protect the system to prevent a national blackout.
It's urging consumers to use electricity sparingly.
- Additional reporting AFP