Johannesburg - There will be deliberate power cuts throughout the country after 18:00 on Thursday, power utility Eskom said.
"We are in the process of implementing this now." said spokesperson Andrew Etzinger.
He said power will be restored by 21:00.
Eskom declared an emergency on Thursday, saying the power system was severely constrained.
It said any extra load or faults in the system would likely result in load shedding.
The power utility also urged consumers to reduce power usage.
"We require voluntary savings of at least 10% in order to manage demand."
"Should
the demand not decrease, load shedding will be implemented as a last
resort to protect the national grid from a total shutdown".
Deliberate power cuts took place countrywide on Wednesday night after two units tripped.
Acting Eskom CEO Collins Matjila warned last week that the country's electricity supply will remain vulnerable during winter, but added that measures were in place to ensure electricity demand was met.
- Sapa with Fin24