Eskom said on Monday it would commence Stage 4 rotational load-shedding from 9 am to 11 pm and continue into Tuesday due to a shortage of capacity.  

Stage 4 load-shedding requires the State-owned utility, which supplies 95 percent of South Africa's electricity, to rotationally take 4 000 MW of demand off the grid at a given period to avoid a total collapse.

Over the weekend, Eskom moved from Stage 2 -- which involves reducing the load by 2 000 MW -- to Stage 4 due loss of power supply from Mozambique's Cahora Bassa hydroelectric system which supplies 1 000 MW to the South African grid but was affected by Cyclone Idai. 

"We remind customers that load-shedding at Stage 4 is no cause for alarm as the system is being effectively controlled," Eskom said in a statement. 

"Load-shedding is a highly controlled process, implemented to protect the system and to prevent a total collapse of the system or a national blackout. During Stage 4 load-shedding, approximately 80 percent of the country's demand is still being met."

Eskom said its maintenance teams were working round the clock to return generation units to the system. 

"We appeal to customers to switch off geysers during the day as well as all non-essential lighting and electricity appliances to assist in reducing demand," it said, reminding consumers to treat all electrical points as live during load-shedding.