Eskom has obtained a court order to stop a wage strike by thousands of National Union of Mineworkers (NUM) members, after talks at the state-run firm stalled.
The company branded the stoppage which started on Monday illegal because its members are prohibited by law from striking, but said its operations had not been affected so far.
The utility has also suspended three senior managers at Koeberg Power Station.
Two were suspended for allegedly leaking information while a third was suspended after a drone crashed on the Koeberg site.