City Power is investigating the cause of a fire that destroyed one of its transformers at its Cleveland substation on Christmas Eve.

The fire plunged several suburbs in the east of Johannesburg into darkness, including Kensington, Jeppestown, Malvern, Heriotdale, Denver and Benrose

The blaze was put out early on Christmas morning after which mop up operations began, City Power said.

“We estimate that repairs will only be completed by tomorrow (Thursday), with power expected to be restored by 7pm should everything go according to plan,” the power utility said City Power spokesperson Isaac Mangena.

“City Power teams of investigators and technicians are currently assessing the extent of the damage caused to the infrastructure, and what caused the fire.

“This investigation will also look at the cost of repairs and replacement to the damaged equipment, especially the transformer which was almost completely razed to the ground and may need a new replacement,” Mangena added.

A new transformer is estimated to cost between R12m and R16m, he said.

“We appeal to customers for their patience while investigations and repair work is conducted.

“We apologise to the residents for the inconvenience caused by this incident, especially on Christmas Day.”