At 1445 GMT, the rand traded at 15.2025 against the dollar, 0.36% weaker than its previous close and around 2.75% down compared to its value in early trade on Monday.
Struggling state power utility Eskom has implemented scheduled power cuts - known locally as loadshedding - every day this week because of faults at its ageing coal-fired plants.
A local government vote on Monday will, meanwhile, test support for the governing African National Congress.
Both factors, along with a broad-based sell of across emerging market currencies on Friday, combined meant the rand took a beating.
"Risk-off mood sees a broad-based sell-off across EM currencies today and with local elections around the corner, we can expect increased price volatility," said Warren Venketas, analyst at IG, adding South Africa-linked commodities had also taken a hit.
Earlier on Friday, central bank data showed private sector credit grew 1.6% year on year in September, compared with a 1.2% expansion in August.
While the country's budget deficit also narrowed, data showed its trade surplus had shrank.
Meanwhile, yields and the bid-to-cover ratio dipped on 1 billion rand of three-month treasury bills sold on Friday.
The yield on the benchmark government bond due in 2030, however, rose 3.5 basis points to 9.640%.
Stocks were down too, with the Johannesburg Stock Exchange's Top-40 Index losing 0.47% to 60,808 points and the broader All-Share Index dropping 0.44% to 67,465 points.
Miners were the biggest losers on the blue-chip index as gold prices hit a more than one-week low, with platinum and palladium prices also suffering.
Shares in the Foschini Group, however, closed 1.73% higher after the retailer swung back to a first-half profit.
(Reporting by Alexander Winning and Emma Rumney Editing by David Goodman and Maju Samuel)
