“The power system is severely constrained today and will remain so for the rest of the week,” chief executive Tshediso Matona said in a statement.
“This is due to technical problems experienced at some of our power stations and the loss of additional generating units.”
Matona said the company had alerted key industrial customers and had required them to reduce their load by a minimum of 10 percent.
“This risk will continue into November,” he said.
“We appeal for sustained savings throughout the day in order to reduce demand on the electricity grid,” he said.
Matona said Eskom would make every effort to avoid power cuts, but as a precautionary measure load-shedding schedules were available on the Eskom website.