At 11:05 a.m. on 1 June 2023, Wellington Electricity’s network protection system cut part of its power supply for safety reasons, causing an outage to 772 homes and businesses across Porirua City.

The cause: a cable strike. A fault crew attended to find a jackhammer driven through a live, high-voltage electricity cable. They immediately made the site safe and had power remotely re-routed and restored in less than an hour, resulting in minimal customer impact.

Sadly, the same cannot be said for the jackhammer operator, who was taken to hospital with facial burns caused by the 11,000-volt electrical flashover that surged through the air as the cable was hit.

This incident could have been avoided. It was found that no mark-out had been obtained by the third-party civil contractor — a critical step in locating underground services. As a result, they may be subject to fines or prosecution, as well as being held liable for any costs incurred.

The events of that day serve as a stark reminder of how a seemingly routine excavation can end with a potentially catastrophic outcome if safe digging practices are neglected. In 2022 alone, Wellington Electricity saw its underground cables struck once a week, on average.

Remember: to keep yourself and others safe, always follow the five rules of safe excavation.

• Plan ahead by lodging your beforeUdig enquiry at least two full business days before starting any excavation.
• Prepare by reviewing utility plans, checking for on-site clues, and engaging a qualified locator before potholing.
• Pothole carefully (if permitted) to confirm the exact location of underground utilities using safe, non-conductive methods.
• Protect exposed infrastructure by communicating with your team, erecting barriers, and marking service locations clearly.
• Proceed only when you’ve planned, potholed, and taken all protective measures.