Eskom spokesperson Khulu Phasiwe has confirmed that stage 2 load shedding will be implemented on Tuesday for 13 hours between 09:00 and 22:00.
Stage 2 allows for up to 2000 megawatts to be cut from the national grid.
The power utility had hoped to avoid load shedding during the week by conducting maintenance, replenishing diesel supplies and topping up water reservoirs for pumped storage schemes over the weekend.
But breakdowns at power generating units mean electricity rationing is set to continue.
In a separate statement on Monday evening Eskom said teams would work through the night to try and bring the units back online.
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