A suspected thief was electrocuted at the Westfield substation near Modderfontein, City Power spokesperson Isaac Mangena said on Saturday.
"The body was found by our technicians on Friday hanging from one of the transformers," Mangena said.
"It is suspected that the suspect tried to vandalize the substation and steal copper and cables from the transformer when he was electrocuted and died on the scene."
It is not yet known how long the man's body had been there.
Mangena said police were investigating what happened and who the man was.
The incident did not affect electricity supply in the area.
Last Friday, a man who was allegedly trying to steal cables at a sub-station in Westdene Recreation Centre was badly burnt.
Mangena said at the time that the cable exploded while the man was allegedly in the middle of the act.
The man was taken to Milpark Hospital. The transformer was badly damaged.
"We would like to warn criminals against toying around with death by fiddling with electricity infrastructure. Vandalism and cable theft cost the City millions of money - money that could be used for other service delivery needs," said Mangena.