The city-wide power outage, affecting Mackenzie Park, Rynsoord, New Modder, Western Extension, the CBD, Northmead, Rynfield, and surrounding areas, has entered its fifth day, with power restoration estimated at 16:00 tomorrow (January 30).

In a statement issued by CoE spokesperson Zweli Dlamini, investigations of the faulty underground 32kVA aluminium cable, which runs between the Morehill and CBD substations along Snake Road, have been damaged due to illegal mining activities along Golden Drive.

The large-scale power outage occurred at 01:22 on January 24, due to attempted cable theft.

Responding teams conducted repairs by installing two joints.

Following line testing, power to the CBD was restored at noon on January 27, with supply to the other areas following before 17:00.

Residents’ celebrations, however, were cut short when another outage occurred just after 18:00.
Ward 27 Clr Lornette Joseph explained that another fault had been detected in the cable.

“Investigations to locate the fault commenced on Wednesday (January 28). Excavations on the line were conducted to expose the cable, and reparation efforts are being made to restore services.”

Blasting at the root

In his statement, Dlamini said: “The cable is installed along Snake Road, between New Modder Road and Golden Drive, where frequent underground blasting, due to illegal mining, takes place.

“Blasting-induced ground vibrations subject cable joints to repeated mechanical stress, which accelerates degradation of stress-control components and insulation interfaces.”

He continued by saying that International Electrotechnical Commission (IEC) guidelines confirm that cable joints are the most failure-prone elements of underground networks, accounting for the majority of in-service failures.

“Uncontrolled blasting significantly increases the risk of unplanned supply interruptions,” he said.

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Effects of mechanical stress include:
• Mechanical fatigue of components.
Continuous vibration causes physical fatigue of conductors and shielding, particularly in crimped or soldered cable terminations.

• Partial discharge and electrical treeing.
Mechanical stress can create microcracks, voids, or gaps in the cable joint insulation.
These defects facilitate partial discharges, which can lead to electrical treeing and ultimately result in insulation breakdown.

“The recurring underground cable failures along the Snake Road area are closely linked to illegal mining activities,” he said.

“According to information received from the energy department, network reliability and asset management are at an increased risk of malfunctioning unless appropriate measures regarding illegal mining activities are implemented.”

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