Transpower identified a need to proactively replace 45 cable joints on the 220kV cable between the Brownhill and Pakūranga substations in Auckland. We were chosen as the primary contractor to deliver this project. This critical piece of infrastructure maintains the electricity supply into Auckland and Northland. This prudent approach in replacing these joints will ensure the cable operates effectively for the next 30-40 years.

Timelapse of joint bay cable repair

The 10.5km cable traverses both rural and suburban areas of East Auckland, starting in farmland in Whitford, through Dannemora, East Tamaki Heights, Botany into Pakuranga.

Two experienced civil contractors, CB Civil and Pipeline Civil were engaged to deliver the project with Northpower. Transpower engaged an overseas specialist for the cable jointing work. Our responsibilities include co-ordinating the cable jointing and civil work, ensuring the health and safety of 80 on-site personnel in peak times, as well as the public in close proximity to the cable. 

The project is being delivered in two phases: June 2024 to June 2025 where 21 cable joints were replaced and June 2025 to July 2026 where 24 cable joints will be replaced. Over 200,000 person-hours have been put towards the delivery of this project so far. 

To ensure a ensure a smooth project delivery for Transpower, Northpower’s project team has effectively addressed and resolved health and safety issues that have emerged during the course of works.

In collaboration with civil contractors and the international specialists, the team has developed several innovative solutions including:

• Portable air-conditioning was brought into the plastic-wrapped work areas to reduce heat stress for workers.
• Rock breaking crews were expanded from two to three members to minimise strain experienced from vibrations and given rotating rest periods.
• A conveyor belt system was co-designed to remove broken concrete from joint bays, reducing heavy lifting for crews and lowering the risk of injury.
• Using a special extension trailer with crane to transport lengths of cabling up to 24m long to site, instead of moving a 30-tonne cable drum between the joint bays. This avoided expensive traffic management plans, and time-consuming site set up, while minimising the risk of injury.

Northpower applies robust safety protocols to keep the public safe at our worksites. Each worksite is cordoned off with large barriers to prevent the public entering a hazardous environment. In cases where the barriers block visibility for motorists, convex safety mirrors and dedicated traffic management is installed to improve visibility.