Stage 2 load shedding will start from 10:00 on Wednesday morning until 22:00 on Sunday night, Eskom announced.
This is due to delays in returning generation units to service at Kusile, Tutuka, Duvha, Kendal and Koeberg power stations.
Unit 1 of the Koeberg power station has been offline since January for maintenance work. It was supposed to return to service last month, but this still hasn't happened. Eskom on Friday suspended Koeberg's general manager Velaphi Ntuli over performance issues related to the delayed return to service.
Eskom said that the situation has been worsened by the high demand for power throughout the day over the past few days due to colder temperatures.
"The emergency generation reserves have been used extensively in the past days to avoid load shedding during the day. This has resulted in these being depleted, reducing available capacity. It is, therefore, necessary to implement load shedding continuously in order to replenish the emergency reserves," Eskom said.
Emergency generation typically involve using open-cycle gas turbines, which run on diesel. It is a very expensive way to generate power.
"Capacity constraints will continue for the foreseeable future and all South Africans are urged to reduce their use of electricity, particularly between 17:00 and 22:00, when the winter demand is the highest," Eskom said.
South Africa has been hit by another bout of load shedding over the past month.