Stage 2 load shedding will continue throughout the week from 5am on Monday 8 November until 5am on Saturday 13 November, Eskom said in a statement on Sunday.
The utility warned it could not rule out higher stages of load shedding should the situation worsen.
"Regretfully, due to the ongoing insufficient generation capacity and the inability to replenish emergency reserves over this weekend, Stage 2 load shedding will continue throughout next week from 05:00 on Monday 8 November until 05:00 on Saturday 13 November," spokesperson Sikonathi Mantshantsha said.
"Since the power system remains volatile and unpredictable, higher stages of load shedding may be required."
He said a "major incident" in Zambia on Saturday had affected the entire Southern African power pool. Imported power from Cahora Bassa reduced by 1 000 MW, while a Tutuka generator also tripped.
Furthermore, a unit at Tutuka power station was forced to shut down while there were further delays in returning a unit each at Lethabo and Majuba power stations.
On Sunday 7 November, a unit each at Medupi and Matla power stations tripped.
Meanwhile, diesel stocks are limited.
Total breakdowns currently amount to 16 693MW while planned maintenance is 5 769MW of capacity.
Eskom teams successfully returned two of the three generators at Kendal Power Station following the shutdown on Friday due to coal constraints, while a unit each at Lethabo and Majuba power station was returned to service from boiler tube leak repairs, Mantshantsha added.