Due to a shortage of capacity, Eskom will this afternoon implement Stage 2 load shedding.
"Eskom regrets that Stage 2 load shedding will be implemented from 4pm to 11pm today due to a shortage of capacity," it said in a tweet on Thursday.
Earlier in the day the power utility said the power system was constrained and vulnerable with generating plant performing at very low levels of reliability.
"With unplanned breakdowns at 12 300MW as at 10am, the probability of load shedding remains, but will only be implemented if absolutely necessary. There is sufficient diesel for our open cycle gas turbines and water at the pumped storage schemes to supplement the shortage of capacity, if required," it said earlier.
Load shedding is conducted rotationally as a measure of last resort to protect the power system from a total collapse or blackout.