Due to a shortage of capacity, Eskom is implementing a second day of rotational load shedding.
In a statement issued in the early hours of Thursday, the power utility said a number of its generating units are still out of service due to breakdowns.
Commencing at 9am, the Stage 2 load shedding is expected to continue until 11pm. Load shedding was also implemented yesterday.
On Monday, the power utility announced that the power system will be constrained this week. It said this was as a result of the loss of additional generation, delays in the return to service of units that are on planned maintenance and limited diesel supply.
Meanwhile, Eskom reminded customers that in some areas, the restoration of electricity following load shedding may take a longer period.
"If customers experience outages for longer periods than announced, please contact your supplier (Eskom or the municipality) as this may be a localised power outage," it said.
Yesterday, the Department of Basic Education said it was monitoring the effect of load shedding on the matric exams.
Learners will sit for their Information Technology exam today which requires electricity availability.