Eskom has said it will be forced to implement stage 2 load shedding between 16:00 and 22:00 on Saturday due to "continued pressure on the national grid".
In Cape Town, city-managed areas will start with stage 1 load shedding at 16:00.
Stage 2 load shedding allows for 2 000 megawatts to be shed. The power utility started with rotational stage 1 load shedding at 09:00 on Saturday.
Load shedding over weekends is rarer than during the week due to a routine decrease in electricity use on Saturdays and Sundays, especially by industry.
On Friday evening the power utility had warned of a high chance of weekend power cuts. It said some generating units were not working due to planned maintenance, while a "higher than expected" number were offline because of technical faults.
Eskom spokesperson Khulu Phasiwe also said the power utility was also making use of the weekend to replenish diesel tanks and water reservoirs for pumped storage schemes to ensure a "better start in the new week". This meant they would mostly not be used over the weekend.
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