At 1510 GMT, the rand traded at 17.3500 against the dollar, about 1% weaker than its Thursday close.
Eskom said in a statement that power cuts would be reduced from "Stage 5" to "Stage 4" at 0500 local time (0300 GMT) on Saturday, before being lowered further to "Stage 2" at 0500 local time on Sunday.
Each stage of power cuts requires an additional 1,000 megawatts of capacity to be shed from the national grid.
The outages -- which have reached record levels in 2022 -- are a major brake on economic growth and source of investor concern.
Eskom has linked the latest power constraints to breakdowns at its coal-fired power station fleet, delays returning some generation units to service, and its diesel budget being depleted, among other factors.
The dollar was buttressed on global markets by data showing U.S. producer prices rose slightly more than expected in November.
The Johannesburg Stock Exchange's All-share index closed 0.1% higher. The South African government's benchmark 2030 bond was slightly weaker, with the yield rising 5 basis points to 10.470%.
(Reporting by Bhargav Acharya and Alexander Winning; Editing by Toby Chopra and Jane Merriman)
