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Milton to Halswell 66kV underground power cable

We’re installing a new underground 66kV power cable between the Milton Street substation and the Halswell substation on Sparks Road to strengthen our electricity network.

From 28 April – early June, we’ll be installing cable ducts on Milton Street between Colombo Street and Strickland Street. The ducts are installed in a trench in the road.

We’re working in stages to minimise disruption. Once we’ve completed the first stage between Colombo and Strickland, we will continue installing ducts along Milton Street towards Frankleigh Street and Sparks Road. We’ll be working in stages during 2025.

To do this work safely traffic management will be in place. This will involve a one-way system and closures on some streets.

Last year we completed in investigation work along the cable route. The information we gathered during this phase was used to determine how best we deliver this project to install the new power cable.

Where we're working

We’re starting construction at the Milton Substation on Milton Street. We’re expecting to complete installing the cable ducts by the end of this year along the 5.6km cable route. We’ll be working in nine stages or work areas - see map below. We’ll let communities know when we’re going to be working in their areas.


Installing the new power cable

The new power cables will be pulled through the ducts we’re installing. Once the ducts are in place, we will reinstate the road surface and reopen the road.

In late 2025/early 2026, we will come back and thread the cable through the ducts and join the cable together at joint bays. Some traffic management will be in place when we come back to pull and join the cable.

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 between two joint bays. Each length of cable is around 800m long and arrives on a large drum, 4.5m in diameter and weighing 27 tons.

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.

Property access

During the day, vehicle access to properties on the side of the road where we are working may be temporarily restricted while we trench past. We’ll place steel plates over the trench, so residents and businesses can access the property when we’re not working.

On-street parking

There will be no on-street parking available where we’re working.

Power supply

There will be no disruption to the power supply to install the new cables. However, along some parts of the cable route we may need to relocate some existing underground power cables. To do this work safely there may be power outages for some customers. You will be notified of any power outages by your power retailer.

Hours of work

The crew will generally work during the day between the hours of 7am - 6pm, Monday - Friday. However, we may need to do early morning or weekend work at times.

Rubbish collection

Your rubbish will be collected as normal. If we are working outside your property, please place your rubbish bins out to the kerb as normal. The crew will move the bins for collection if necessary and return them to outside your property.

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. In June last year we finished the first of these projects between the Bromley Substation and Milton Substation. This was the first of 12 new cables that will create new ring circuits in Christchurch City. We’re now working on the next of these cables, between the Milton Substation and the Halswell 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.

We understand that construction work is inconvenient. Our crews are working hard to get the work done as safely and quickly as possible. We thank our community for their patience while we complete these essential works.


Stay up to date

We'll keep this page up to date with the latest information on this project and how it's progressing.

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.

We’re installing a new underground 66kV power cable between the Milton Street substation and the Halswell substation on Sparks Road to strengthen our electricity network.

From 28 April – early June, we’ll be installing cable ducts on Milton Street between Colombo Street and Strickland Street. The ducts are installed in a trench in the road.

We’re working in stages to minimise disruption. Once we’ve completed the first stage between Colombo and Strickland, we will continue installing ducts along Milton Street towards Frankleigh Street and Sparks Road. We’ll be working in stages during 2025.

To do this work safely traffic management will be in place. This will involve a one-way system and closures on some streets.

Last year we completed in investigation work along the cable route. The information we gathered during this phase was used to determine how best we deliver this project to install the new power cable.

Where we're working

We’re starting construction at the Milton Substation on Milton Street. We’re expecting to complete installing the cable ducts by the end of this year along the 5.6km cable route. We’ll be working in nine stages or work areas - see map below. We’ll let communities know when we’re going to be working in their areas.


Installing the new power cable

The new power cables will be pulled through the ducts we’re installing. Once the ducts are in place, we will reinstate the road surface and reopen the road.

In late 2025/early 2026, we will come back and thread the cable through the ducts and join the cable together at joint bays. Some traffic management will be in place when we come back to pull and join the cable.

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 between two joint bays. Each length of cable is around 800m long and arrives on a large drum, 4.5m in diameter and weighing 27 tons.

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.

Property access

During the day, vehicle access to properties on the side of the road where we are working may be temporarily restricted while we trench past. We’ll place steel plates over the trench, so residents and businesses can access the property when we’re not working.

On-street parking

There will be no on-street parking available where we’re working.

Power supply

There will be no disruption to the power supply to install the new cables. However, along some parts of the cable route we may need to relocate some existing underground power cables. To do this work safely there may be power outages for some customers. You will be notified of any power outages by your power retailer.

Hours of work

The crew will generally work during the day between the hours of 7am - 6pm, Monday - Friday. However, we may need to do early morning or weekend work at times.

Rubbish collection

Your rubbish will be collected as normal. If we are working outside your property, please place your rubbish bins out to the kerb as normal. The crew will move the bins for collection if necessary and return them to outside your property.

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. In June last year we finished the first of these projects between the Bromley Substation and Milton Substation. This was the first of 12 new cables that will create new ring circuits in Christchurch City. We’re now working on the next of these cables, between the Milton Substation and the Halswell 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.

We understand that construction work is inconvenient. Our crews are working hard to get the work done as safely and quickly as possible. We thank our community for their patience while we complete these essential works.


Stay up to date

We'll keep this page up to date with the latest information on this project and how it's progressing.

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.

Page last updated: 16 Apr 2025, 09:46 AM