The electricity grid remains constrained with a high probability of load shedding between 17:00 and 21:00 on Thursday evening, Eskom has said.
Consumers have again been asked to use electricity sparingly.
In a statement issued on Thursday morning, the power utility said industrial action continued to impact operations at its sites.
On Wednesday, it met with employees at dispute resolution body the Commission for Conciliation, Mediation and Arbitration, or CCMA, in an attempt to resolve an impasse over wage negotiations. It was due to meet again on Thursday, it said.
It remained "hopeful" that all parties would put the country first as it worked to find an amicable solution.
The state-owned company posted a R2.3bn loss for the year ended March 31.
Despite warnings about possible power outages, Eskom did not implement load shedding on Wednesday or on Thursday morning.
However, the company said that as a result of the industrial action, Eskom direct customers may experience a delay in response and restoration times of localised power outages.
It said that police would continue to maintain order and safe access to power stations as these are National Key Points.
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