Eskom says there is an increased probability that load-shedding will be implemented on Thursday.
"There is an increased probability of load-shedding tomorrow as some generation units will be taken off the system to conduct emergency repairs," the power utility said in a statement on Wednesday evening.
"As the system is constrained, vulnerable and unpredictable, any additional shift in generating performance could lead to load-shedding at short notice. We will utilise emergency reserves to supplement the supply overnight."
Unplanned outages or breakdowns were at 11,773MW at 5.30pm on Wednesday, while planned maintenance was at 4,602MW.
"Eskom reminds South Africans that there is a possibility of increased load-shedding over the next 18 months as we are conducting critical maintenance to restore the ageing plants to good health. Every megawatt counts," it added.
