Eskom says Stage 2 rotational load shedding will continue today and tomorrow, with a high probability over the weekend.
Eskom on Thursday said there is a shortage of capacity and a higher demand for electricity.
"The probability of load shedding remains high for the weekend. Eskom will continue to provide regular updates," the company said in a statement.
Eskom said there is an increased possibility of load shedding over the next 18 months, as it is conducting critical maintenance to restore its ageing plants.
Any additional shifts in the system, Eskom said, may require a change in the load shedding stage.
"We therefore request customers to use electricity sparingly and to reduce demand during this period of load shedding.
"As we continue to replenish the emergency reserves at our pumped storage schemes and open cycle gas turbines (OCGTs), we will continue to explore the pilot programme of providing load shedding respite during the morning and evening traffic rush hours in the week.
"However, this is not possible today owing to the available generating capacity and the need to replenish emergency reserves," Eskom said.
Unplanned outages or breakdowns were at 11 567MW as at 06:00 this morning. Critical maintenance is being done on units that are currently on planned outages as well as some of those on unplanned outages to ensure timeous return to service.
Customers can revisit their load shedding schedules on the Eskom (https://loadshedding.eskom.co.za) or local municipal websites, depending on their electricity supplier, to review amendments.