The electricity grid is under "severe pressure", Eskom warned on Thursday afternoon, pleading with the public to switch off all unnecessary appliances, pool pumps, and geysers.
The power utility typically makes such requests early in the evening in a bid to alleviate pressure on the grid and avert load shedding.
It will be implementing load reduction – rolling blackouts in targeted areas – between 17:00 and 22:00 on Thursday in parts of Limpopo and North West, as well as in parts of the Free State, Gauteng and Limpopo between 05:00 and 09:00 on Friday.
But should load shedding be implemented any time soon, those who rely on their own generators in the event of a blackout will be unable to top up their diesel supplies, following an earlier announcement that the retail sale of petrol and diesel in containers was no longer allowed owing to the threat of fuel shortages.
Eskom's plea for the public to reduce usage followed an earlier announcement that its Astra substation had caught fire due to the theft of cables, which left residents of Kanana Park, Sweetwater and Wheelers farm without power.
Eskom has been fighting a long-standing battle, unrelated to the current riots, against vandalism, illegal connections and cable theft, which affect electricity supply. But this week, it said it was having trouble difficulty attending to network faults due to the protests.
"Technicians are trying their best to access the affected areas," it said on Wednesday.
Gauteng – which has been battling widespread riots and looting – has also seen multiple electricity outages across the province this week.