Electricity supplier Eskom warned on Monday that supply will be tight over the next few days due to maintenance on generating units.
"Our supply capability on the system for the next few days is in a tighter condition due to the current units on outage," Eskom said in a statement.
"The power system will remain tight until new generating capacity comes on stream and essential generation maintenance is done."
The power utility called on people to reduce electricity usage while the planned maintenance on the generating units continued.
Eskom said the air-conditioning load was expected to increase from Tuesday because warm weather had been forecast.
"Eskom continues to make progress with its programme of planned maintenance but the system remains tight," it said.
"We urge all South Africans to partner with us to save 10% of their electricity usage especially during peak periods, from 5pm to 9pm."
Eskom said if consumers saved 10% it would make it "significantly easier" to manage the power system during this time. – Sapa