South African power utility, Eskom again warned of a constrained system on Wednesday evening and urged consumers to use electricity sparingly.
The company put out a similar warning on Tuesday night.
"Eskom requests the public to continue reducing electricity usage as the system is constrained following breakdowns," it said in a statement.
"Eskom wishes to appeal to the public to continue reducing electricity consumption during the peak hours tonight as the generation system is currently constrained. While some generation units were returned to service last night, breakdowns occurred at a further two generation units today."
The company's teams were "working hard" to return to service the two units that tripped on Wednesday at Medupi and Matimba power stations, it said.
The teams had to take off a unit to deal with emission requirements at Kendal, Majuba and Lethabo on Tuesday.
"While the system remains constrained, we hope to avoid loadshedding, with the help of the people of South Africa.
"We urge the public to use electricity sparingly by switching off non-essential appliances in order to maintain the integrity of the system. With your assistance yesterday, we successfully managed to meet the peak demand, and for that we thank the public."
South Africa has been experiencing intermittent loadshedding - or rotational blackouts - for the past few years, which have severely affected the country's ailing economy. A combination of poor planning, insufficient maintenance and rampant corruption and mismanagement have been blamed for the indebted power utility's decline.
African News Agency (ANA)