Phase 6 load shedding will be introduced on Tuesday morning from 05:00 until further notice.
Eskom said on Monday that two further units at Lethabo and Matla power stations must be switched off for urgent repairs.
A total of 16,210 MW is currently unavailable due to technical problems. A total of 5,894 MW is currently switched off due to planned maintenance.
A unit each at Kriel and Medupi power stations had to be switched off since yesterday for repairs. In the same period, one unit each was switched on at Arnot, Kendal, Kriel and Lethabo power stations.
The delay in restarting units at Hendrina and Tutuka power stations has also contributed to the current capacity constraint.
“Eskom teams are working tirelessly to turn these units back on,” said the power supplier.
The public is requested to consume electricity sparingly and switch off non-essential appliances.