A fire at a substation has caused widespread power outages and water cuts across Johannesburg.

At around 05:00 on Friday, the Eldorado Park substation caught fire, causing almost the entire suburb and surrounding areas to be without electricity. By 09:30, the fire had been extinguished, said City Power in a statement.

City Power staff were initially unable to enter the substation due to safety concerns, with the area engulfed in smoke.

However, by midday, teams had managed to access the substation and started assessing the damage.

They discovered that the fire had damaged one transformer and a second one had been affected by the heat.

Testing would be carried out to determine if the second transformer could be used.

The control room had also been badly damaged. The fire caused several substations upstream to trip.

These included Orlando, Fordsburg, Pennyville, Mayfair, Mondeor, Nirvana, Nancefield, and Eikenhof.

All the substations had since been restored, except for Nancefield and Nirvana.

These were expected to be restored later on Friday. The outages affected water supply to Roodepoort, Lenasia and Soweto, said Johannesburg Water.

The city had been plagued by power outages over the past week.

News24 previously reported that nearly 2 000 power outages had occurred in Johannesburg in the past week.

According to City of Johannesburg acting MMC for Environment and Infrastructure Services, Leah Knott, most of these were the result of inclement weather, increased demand and ageing infrastructure.

Load shedding had further frustrated the power utility's efforts to reconnect the electricity.