DUCT BANK INSTALLATION - WELLINGTON ELECTRICITY

Client: Wellington Electricity

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Location: Strathmore, Wellington (NZ)

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Service: Full civil delivery including duct supply, trenching, installation, and reinstatement

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Project overview

Wellington Electricity entrusted Marais Laying NZ with the delivery and installation of an underground duct bank to support power and communications infrastructure in the eastern suburb of Strathmore. The objective was clear: enhance the local grid’s capacity and resilience while laying the groundwork for future service demands.

The project involved two key segments, with a focus on establishing a robust pathway for 11kV and future 33kV electrical cables, as well as high-speed communications lines.

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Scope of works

Segment: Raukawa Street to Ira Zone Substation

Marais Laying NZ completed the installation of a duct bank system comprising:

• 5 x 150mm uPVC ducts designated for 11kV power distribution

• 2 x 100mm rigid uPVC orange ducts for future communications infrastructure

This infrastructure was designed to allow seamless integration of future cables, reducing the need for repeated civil works in the same corridor.

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Key deliverables

• Materials procurement & supply: Full delivery of ducting materials, bends, protective components, and compliant warning systems.

• Traffic management: Design and implementation of a comprehensive traffic management plan to minimise disruption and ensure public safety throughout construction.

• Civil works execution: Precision trenching, duct placement, backfilling, and reinstatement to meet:

  • Wellington Electricity technical specifications

  • Local Road Controlling Authority (RCA) regulations

  • Industry-standard best practices.

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Challenges & technical considerations

Operating in a densely populated urban environment required careful navigation of logistical and technical challenges, including:

• Pedestrian and vehicle management: Active public zones necessitated meticulous planning to safeguard both residents and road users.

• Stakeholder coordination: Ongoing collaboration with Wellington Electricity, subcontractors, and regulatory authorities to ensure alignment and progress.

• Engineering accuracy: Strict adherence to trench geometry and duct spacing to support the long-term integrity of future cabling.

• Reinstatement standards: Restoration of road surfaces and public spaces to pre-works conditions was a priority to preserve community satisfaction.

Outcomes & long-term impact

The duct bank installed between Raukawa Street and the Ira Zone Substation now forms a vital part of Wellington’s evolving energy infrastructure. Key benefits include:

• Future-Proofed Design: Accommodates future 33kV and 11kV circuits as well as communication lines.

• Enhanced grid resilience: Supports a more robust and adaptable distribution network.

• Improved maintainability: Facilitates efficient access for future maintenance or upgrades.

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Marais Laying NZ’s contribution to Wellington Electricity’s infrastructure strategy reflects our commitment to high-performance delivery and sustainable engineering. This installation not only supports current utility demands but anticipates the technological and energy needs of tomorrow. In an urban context where space, safety, and serviceability are paramount, our team delivered with precision, professionalism, and foresight.