Power utility Eskom has announced that it will implement Stage 4 load-shedding from 12:00 on Wednesday to 05:00 on Friday.

Thereafter Stage 2 load-shedding will continue until 05:00 on Saturday.

"Over the past 24 hours a unit each at Medupi, Kusile and Matla power stations tripped, while a unit each at Lethabo and Arnot power stations were forced to shut down. This constrained the power system further, requiring extensive use of emergency reserves, hampering the recovery of these reserves.

"Some generating units have returned to service and we anticipate another two units to return to service during the day. In addition, Koeberg Unit 1 is expected to return to service today and begin ramping up to full output within 48 hours," the utility said in a statement on Wednesday morning.

Total breakdowns currently amount to 14 957 MW, while planned maintenance is 5 301 MW of capacity.

"We remind customers that load-shedding is implemented as a last resort to maintain the stability of the power system regardless of the stage of load-shedding. The implementation of Stage 4 load-shedding is, therefore, no cause for alarm as the power system remains to be (sic) effectively controlled," it said.