Thousands of workers at South African power stations plan to join a strike from tomorrow over pay at state-run utility Eskom.
A strike had initially begun on Monday when around 1,500 members of the National Union of Mineworkers (NUM) downed tools after wage talks stalled.
Eskom branded the stoppage illegal because its members have been prohibited by law from striking.
Operation are said to not have been affected so far.
All of the union’s 15,000 members at the utility, which is close to a third of Eksom’s workforce, are expected to stop work.
In a statement the union said: “It is going to be a total withdrawal of labour by our members. NUM members will be striking for the right to strike at Eskom.”