Eskom has warned that its power system is "severely constrained" this afternoon as the return to service of five generation units is delayed, while two units have tripped.
"We urge the people of South Africa to reduce electricity consumption in order to help us power the country through the evening peak," Eskom said.
According to the power utility, the return to service of two-generation units at the Tutuka power station has been delayed as well as a unit each at Duvha, Matimba and Kusile power stations.
"An additional unit at Tutuka tripped this afternoon while Kusile's unit 1 has been shut down."
The Eskom team is working hard to return these units to service, the utility said.
"These breakdowns have added to the approximately 5 500MW of capacity out on planned maintenance while unplanned maintenance has risen to almost 11 000MW," Eskom explained.
Eskom said the constrained system might persist for the rest of the week.
"Eskom requests your assistance in using electricity sparingly so we may be able to supply the country through the evening peak demand period," Eskom added.