Eskom warned on Monday that load-shedding could be implemented at short notice due to a constrained national power grid.
The power utility said there were delays in returning units to service and it had lost multiple generation units and urged the public to reduce electricity consumption.
It said while no load-shedding was planned, consumers needed to reduce their consumption of electricity as further losses of generation capacity would result in load-shedding at short notice.
"The loss of multiple generators over the weekend, as well as delays in returning some generation units to service, has made for a constrained power system this afternoon. Eskom is working on returning a generation unit each at Matimba, Duvha and Arnot power stations to service before the evening peak," Eskom said.
On Monday a generation unit each at Arnot, Kendal, Matla and Tutuka power stations were returned to service, but Eskom is still heavily reliant on emergency reserves to meet demand in the evening.
"Emergency reserves are healthy to assist in reducing the supply deficit. We have 4,533MW on planned maintenance, while another 13,601MW of capacity is unavailable due to breakdowns," Eskom said.