Eskom's Megawatt Park in Sunninghill, Johannesburg was on lockdown on Monday after Soweto residents barricaded all entrances leading to the offices.
Disgruntled residents embarked on the protest action after the power utility cut electricity to some parts of the township over non-payment of bills.
Staff members who were already inside the premises were unable to leave while those who were outside were unable to gain access.
Eskom had warned residents to pay up or the utility would not repair faulty and damaged substations and transformers.
News24 previously reported that the township alone owes Eskom over R17bn in unpaid electricity bills.
Last week Johannesburg mayor, Herman Mashaba, promised to engage with Eskom officials over the power utility's threats. He said he had received complaints from residents demanding his intervention.
Eskom spokesperson Dikatso Mothae said residents seemed not to be pleased with the utility's stance of requesting access to audit meters in order to fix the outages experienced in some parts of the area.
"The reason why we are saying this is because we have seen that to just reconnect infrastructure in those areas, without dealing with the root cause of illegal connections, we found we just reconnect then the infrastructure three days later fails or explodes and we have to replace [it] which is quite expensive," Mothae said.
She said the groups who blocked entrances were from Protea South and Dlamini. No damage to property was reported and employees were safe, Mothae added.
The residents handed over a memorandum and have since dispersed.
Mothae said the memorandum has been received and the power utility would revert to the residents in due course.
"With these issues, we continue to engage with communities as best as we can but what is paramount is that they allow us in to do those meter audits," she said
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