Eskom is declaring a dispute with trade unions.
Unions say they will only agree to a wage agreement if Eskom does not discipline employees who went on strike.
The utility says it cannot agree to this precondition.
During an intervention by the CCMA, three unions agreed to a three-year wage proposal.
The agreement would see an increase of 7.5 percent this year, and 7 percent over the next two years.
Employees would also receive a once-off cash payment of R10,000.
But unions now say they will only agree if Eskom assures no employee will be dismissed for taking part in industrial action.