Large parts of Johannesburg -- including the suburb where Nelson Mandela is recuperating following his hospital release -- were without electricity Thursday after hundreds of technicians with the city's power distributor went on strike, AFP reports.
Around 200 technicians at Johannesburg City Power refused to work overtime on Wednesday afternoon, said Louis Pieterse, a spokesman for the company providing power to South Africa's economic hub.
"They worked during the day and downed tools at 04:00 pm (1400 GMT), saying they won't work after hours," Pieterse was quoted as saying by the Sapa news agency.
At the start of September, the company introduced evening shifts in an effort to decrease power outages in Africa's largest economy, which has been facing electricity shortages for years.
"Unfortunately, there is a certain level of resistance by some employees which has resulted in unlawful work stoppages," Pieterse said.
He said that a court order issued early on Thursday has ordered the technicians back to work, but so far they have not done so.
Power cuts in the city's western and northern parts caused traffic delays, according to the metro police.
The suburb of Houghton, home to Mandela's residence, was also affected.
Mandela has been receiving intensive care at his home in Houghton since being discharged from hospital at the weekend following a three-month stay.
The house has a generator and city contractors delivered a second one late Wednesday, according to local media.
The strike occurs in a tense labour environment, with mass wage stoppages across the country.