According to the power utility, Eskom, this is due to a loss of 900 MW imports from Mozambique.
Earlier on Saturday morning the power utility said it would be implementing Stage 2 load shedding from 08:00 to 23:00 due to a shortage of capacity and a loss of additional generating units.
But just after 10:00 the power utility alerted consumers via Twitter that load shedding would be kicked up to Stage 3.
“The situation remains tight and volatile, and we may have to implement further load shedding should the situation deteriorate,” Eskom said in a statement.
“Depending on how quickly we can restore power, this may impact the prognosis for tomorrow and next week,” the power utility warned.