City to Milton Street 66kV underground power cable
We're currently completing investigation work to help plan our work to install a new 66kV underground power cable between the Oxford/Tuam Substation in the City, to the Milton Street Substation.
From 29 March to late April 2026, we’ll be working at night to carry out investigation work between the Milton Street Substation and the Oxford–Tuam Substation. This work involves digging small trenches in the road to check ground conditions and underground services.
This investigation work is required to understand the underground services and ground conditions where the cable will be installed. This information will be used to inform our planning for how we best deliver this project at a later date.
Where we're working
We'll let communities know when we're going to be working in their areas. We'll keep this page up to date with the latest information on this project.
Installing a new power cable
We'll use a construction method called ducting to help minimise disruption from this work. Installing ducts allows us to speed up the cable laying process. Once all cable ducts are laid in the road, we install the new power cable.
The new cable is pulled through the ducts using a winch. We pull the cable through the ducts carefully as the cable is heavy and not very flexible. Once all the lengths of cable are installed, we join the cables together at the joint bays.
Traffic management will be in place while we complete this work. This may include:
- Lane diversions or closures
- One-way systems
- Road closures
- Detours
- Manual traffic control - stop/go, or temporary traffic lights
- Reduced speed limits
- Reduced on-street parking
Why we're strengthening our network
Some of our underground cables in Christchurch City are 40-60 years old. While the cables still work, and will continue to do so under normal conditions, they are more vulnerable to earthquakes. If another large earthquake occurs, these cables could develop faults and be difficult to repair.
To strengthen our network, Orion is replacing these older cables. We have recently completed the second of these projects, installing a new cable between the Milton Street Substation and the Halswell Substation in March 2026. We’re now planning the next of these cables, between the Oxford/Tuam Street Substation and the Milton Street Substation.
These new ring circuits will:
- Allow us to shift power around the network, so if there's a fault, we can re-route power to keep customers connected.
- Enable us to progressively retire the old cables.
The new cable uses the latest technology and is designed to support future growth.
These works are essential to powering a cleaner and brighter future with our community. Installing the new power cable will strengthen the resilience and security of the power network and provide for the future growth of our city.
Stay up to date
We want to work with the community to minimise the disruption of this work. If you have any questions about this work, you can reach us at haveyoursay@oriongroup.co.nz or anytime day or night through our Customer Support team on 0800 363 9898.
