The City of Johannesburg has warned that cable theft will likely increase after Eskom announced the implementation of Stage 6 loadshedding.

On Wednesday, Eskom reported breakdowns amounting to a staggering more than 20 000MW.

The embattled power utility said Stage 6 loadshedding would continue until Friday at 05:00, and would then be reduced to Stage 5.

On Thursday, the City of Johannesburg warned that the lengthy outages would put pressure on its ageing infrastructure.

"Johannesburg's ageing network is simply not designed to be powered up and down and to withstand the impacts of rush current several times a day without running the risk of severe technical faults," said City of Johannesburg Environment and Infrastructure Services MMC Michael Sun.

Sun warned that the lengthy blackouts would also allow cable thieves to operate without running the risk of high-voltage electrocution.

He said the City had deployed all available personnel, including team leaders and management staff, to ensure the speedy resolution of outages and faults.

"To every single Joburger, I feel your pain. But we need to pull together now and play our part by using electricity sparingly. Do not overload the system and run the risk of surges in your home and business when your power comes back by immediately activating all your appliances," he said.

News24 previously reported that Eskom called off the planned outage of Koeberg unit 1 at the eleventh hour, as the utility scrambled to avoid moving to Stage 7 loadshedding.