City Power said on Thursday load-shedding was straining its resources, with some substations unable to return to normal after power is restored.

This left customers without power for longer.

“The past two days, Tuesday and Wednesday, were the worst, with most of our substations failing to switch on after restoration, with Randburg the hardest hit,” City Power said in a statement.

It said the recent bout of load-shedding, announced by Eskom this week and expected to last until Sunday night, comes as City Power is already overstretched by an increase in demand  for winter, while battling rampant cable theft and illegal connections.

On Thursday afternoon, City Power teams were struggling with some of the substations that were still off.

These include  Randburg 11kv sub, Northriding 11kv sub, Brynorth 6.6 kV sub, Beyers 11kv sub, Randburg 6.6 kV sub and Fontainebleau 6.6kv sub.

“While the majority of these fail on restoration due to system overload, we have found some failures were caused by vandalism and cable theft happening during the load-shedding, as was the case with Founders Hill switching station near Greenstone.”

The power utility said  the ageing infrastructure also cannot be ignored.

“We urge customers to also help reduce the inrush current by switching off heavy appliances during load-shedding.

“These include geysers, pool pumps, heaters and stoves. They can be switched back on, gradually, a few minutes after power is restored.”