Contracting Capabilities

Northpower provides contracting services across the North Island including engineering, infrastructure management and maintenance and construction.

South Waikato grid connection

Project Name:  South Waikato grid connection

Location: South Waikato

Start date: December 2021

Completion date: March 2023

Key people involved: Bruce Curle, Sharie Kiripa, Nick Gouge, Gavrilo Kovacevic, Deon Steyn, Patrick Watson, Marty Drower, Gareth Hoskin, Andy Cooper, Cormac Jardine, Richard Taylor, Josh Taylor

Project partners: Powerco

In December 2021, Northpower was awarded the Putāruru South Waikato National Grid Connection project by Powerco.

Connecting South Waikato

The $43m project, which connects the Arapuni and Putāruru areas, establishes a 110kV circuit between Transpower’s Arapuni substation and a new transformer at the existing Powerco Putāruru substation.

The project required a mix of overhead lines and underground cables to balance cost-effectiveness, safety and reliability. Overhead lines were predominantly used due to their cost efficiency and ability to fit within road reserves. However, underground cables were employed in sections where safety considerations or existing infrastructure constraints dictated their necessity.

The project encompassed several key components:

  • Construction of 11kV enabling works between Putāruru and Arapuni, facilitating the installation of the 110kV line, including the relocation of both HV and LV circuits.
  • Establishment of new substations at Tirau, Hinuera, and Putāruru, along with the installation of new 11kV and 33kV boards at each site.
  • Implementation of 33kV interlinking between Putāruru – Tirau and Hinuera – Tirau.
  • Connection of new GXP’s at Putāruru and Arapuni.
  • Construction of 14km of 110kV line between Putāruru and Arapuni, comprising 10.5km of overhead conductor and 3.5km of underground cable, traversing various terrains including streams, rivers, bush, roadsides, and farmland.


km of 110kV line


km of overhead conductor


km of underground cable

Innovative solutions

Innovative solutions were needed to tackle the complexity of the project, and the diverse topography of the region. Specialist helicopter contractors were engaged for efficient and safe stringing of overhead lines in challenging areas to minimise the environmental impact of works, and a rope access system was employed to install the 110kV cable within a stainless-steel pipe across the Waikato River to the Mercury Bridge.

Effective collaboration and communication

The project was completed on time and within budget, building on Northpower’s strong reputation with Powerco. Key to the project’s success was the high degree of communication and collaboration between stakeholders and field teams.

Communication with key customers of Powerco and Transpower, along with local iwi, councils, residents and the Pokaiwhenua trust was critical to meeting the short construction timeframe.

Enhancing reliability and resiliency

The project has significantly enhanced the reliability and resilience of the electricity network in the South Waikato region. It has provided N-1 security capacity, enabled back-feeds and provided increased resilience to communities across Powerco’s network.

The new grid connection plays a vital role in ensuring a reliable electricity supply to accommodate the growing communities in the South Waikato region, both presently and in the future. By diversifying the sources of electricity, the project will minimise disruptions caused by faults or maintenance in the existing transmission line, ensuring a more reliable electricity supply to over 11,500 homes and businesses. This will not only meet current demands but accommodate for future growth too.