Brownhill-Pakuranga cable remediation

Last updated: 13 Dec 2023

Transpower plans to replace 45 joints at 15 locations on an underground electricity cable between the Brownhill and Pakuranga substations in south-east Auckland in a two-to-three-year work programme starting in 2024.

We are taking a prudent approach following two faults in cable joints on this circuit in the past three years by replacing all joints on the cable in a planned way. The issue is unforeseen and unexpected, but replacing these joints returns this important cable to its intended condition, so it can operate effectively for its expected 30–40-year life.

We assessed a range of other remediation options for the cable and concluded that replacing the joints will give the best overall outcome for electricity users in the region.

This is a complex civil works project involving the excavation of a city bus-size area in 15 locations across approximately 10 kms of cable route to access the cable joints. We anticipate it will take around four months to complete the work for each joint bay, or longer for some more complex sites.

Ten of the cable joint bays are located within roads or on roadsides, two are in council reserves, two are on private property and one is on Transpower property. We will work closely with local communities, mana whenua and other stakeholders to understand any impacts and find the best solution to mitigate or avoid these.

Secure electricity supply

The electricity supply into Auckland and Northland is secure and will continue to be secure during the works. This is because there is a companion cable on the circuit between Brownhill and Pakuranga, and we have recently built a temporary bypass line in north Waikato to provide additional security and ensure peak demand can be met.

Planned project timeline

  • November 2023 – completion of our business case
  • July 2024 – physical site work expected to start

Further communication and feedback

We will communicate directly with local communities, mana whenua and other stakeholders as the project progresses and we will also provide regular public updates on this page. You can also sign up to the project e-newsletter.

We welcome any questions or your feedback on our planned remediation approach via email to [email protected].


The 10.5km cable is one of two supplying electricity into Auckland and Northland at times of peak demand as part of the high-capacity double circuit Pakuranga-Whakamaru transmission line.

Map of Brownhill to Pakuranga cable showing joint bay locations


Brownhill Pakuranga underground cable map 01


Brownhill Pakuranga underground cable map 02


Brownhill Pakuranga underground cable map 03