A major milestone has been reached with undergrounding now complete along the Methven Highway (SH77) between Ashburton and Methven, bringing EA Networks close to finishing a long-running programme to remove overhead power lines from key state highways across Mid Canterbury.

Delivered in stages over more than a decade, the project has made SH77 safer and more reliable for the region's electricity network.

By placing power lines underground, the risk of vehicle-related incidents involving power poles is significantly reduced. The network is also less exposed to weather, vegetation and wildlife, resulting in fewer outages for customers.

"The completion of the Methven Highway underground conversion between Ashburton and Methven is a significant milestone for EA Networks, our community and for visitors travelling through our region," says Pete Armstrong, EA Networks' General Manager Networks. "The decision was taken to replace the overhead lines at the point of renewal with underground cable, resulting in significant benefits in road safety, increased reliability for our customers and lower costs over the life of the asset from reduced faults, repairs and avoided tree cutting."

Myles Connew, EA Networks' General Manager Contracting, says the project was delivered using a staged approach to minimise disruption to customers and road users. Rather than replacing poles one by one, new underground cables were installed alongside the existing network.

Customers were then gradually switched over, allowing most work to take place without planned outages. A specialised ploughing method was used to install cables at a slow, continuous pace, reducing the need for extensive traffic management.

"From an operational perspective, that aspect of the work was straightforward and efficient," Connew says.

"For our customers, it delivers clear benefits in terms of safety, reliability and visual impact."

The project was made possible through collaboration with contractors, partners and the wider community.

Local firm Greg Donaldson Contracting played a key role in developing the specialised equipment used to install the cables. Support from the NZ Transport Agency Waka Kotahi also helped make the early stages of the project possible.

The programme also reflects the long-term vision of past and present EA Networks teams and leaders, who recognised the safety and reliability benefits of undergrounding.

"We also installed fibre alongside the electricity cable, giving residents the option to connect to reliable internet as well," says Peter Lindsay, EA Networks Planning Engineer.

"Undergrounding is a strong long-term solution for our network and it puts Mid Canterbury in a very good position for the future."

Armstrong acknowledges the people behind the work.

"My congratulations go to our hardworking design and field teams, along with our civil contractors, for the sustained effort required to deliver this multi-year project," he says.

The Methven Highway work forms part of a wider programme that has seen extensive undergrounding across the district, including SH1 between Rakaia and Rangitata, sections of the Upper Rakaia area and ongoing improvements across rural townships and key routes.

This work aligns with EA Networks’ long-term Asset Management Plan, which guides investment decisions to ensure a safe, reliable and resilient electricity network for the region.