It explained that if the system keeps getting overloaded, it could result in substation and transformer explosions which is a threat to the safety of people and property in affected areas.
Lejweleputswa and Thabo Mofutsanyana districts in the Free State were cut-off between 6am and 9am.
In Gauteng, parts of Soweto, the Vaal and West Rand areas were also cut-off between 5am and 9am.
Thousands of households in the Mfolozi, Mtubatuba, New Castle, Ray Nkonyeni, Mandeni and Msinga areas in KwaZulu-Natal were expected to be affected.
In Limpopo, the Lenyenye and Mamitwa areas in the Mopani district were shut down too.
The power utility advised customers affected to not bother logging in any complaints during these power cuts.
“During the load reduction implementation, customers are urged to switch off all their electrical appliances to avoid possible damage due to power surges when supply returns,” said Eskom.
“Failure to do so may lead to transformer trips or failures and damage to household appliances when supply is restored,” the power utility added.