Contact

Project: EGL2 Ducting Installation – Wren Hall

Key Project Details

Client:

  • NKT

Project: EGL2 Ducting Installation – Wren Hall

Location: Wren Hall

Start date:

  • February 2026

End Date

Duration:

  • 12 months

Contract Value:

  • £1.75m

The Challenge

As part of the Eastern Green Link 2 (EGL2) project—the largest ever project in the UK transmission system—Aaron Engineering Group was required to deliver cable ducting infrastructure at Wren Hall connecting two new DC converter stations to the National Grid substation. The project involved installation of two separate 400kV circuits (Circuit 1: 225m and Circuit 2: 260m), each requiring different ducting specifications and precast concrete troughing systems. Works were executed within a constrained site environment with significant congestion, requiring meticulous planning, coordination, and execution to ensure alignment with programme and quality expectations. The restricted working space demanded safe excavation practices, controlled sequencing, and phased construction approaches to minimise the duration and extent of open excavations whilst maintaining programme milestones and preventing impact on adjacent infrastructure and ongoing site activities.

What We Did

Aaron Engineering Group delivered comprehensive ducting installation works at Wren Hall as part of the EGL2 programme. Our scope included:

Cable Ducting Installation:

  • Installation of 110mm multipath fibre ducting Class 1 PVC across both circuits
  • Installation of 110mm Class 1 PVC ducting
  • Installation of 250mm Class 1 PVC ducting for cable containment
  • Installation of 25mm ID ducting for temperature sensing equipment
  • Total linear installation: 485m, with 2910m of ducting installed across the two circuits

Precast Concrete Troughing Systems:

  • Installation of precast concrete troughing systems to support both circuits
  • Integration of trough systems with ducting installations

Safe Excavation and Construction:

  • Extensive battering implemented to ensure safe excavation practices
  • Controlled excavation sequencing to minimise open trench duration and extent
  • Phased construction approach to reduce site congestion and manage logistics
  • Safe working practices maintained throughout all excavation activities

Digital Quality and Site Management:

  • On-site use of tablets to complete ITPs (Inspection and Test Plans) in real-time
  • Direct upload of quality functions to digital quality logging systems
  • Digital reporting, inspections, and record management for full project traceability
  • Paperless site management system implemented to minimise paper use and increase efficiency

Sustainability:

  • All construction plant complied with Euro 6 emissions standards to reduce environmental impact

The Outcome

  • Two 400kV circuits successfully installed with ducting and precast concrete troughing systems complete
  • 485m of linear ducting installed with precision alignment to circuit routes
  • 2910m of total ducting installed across varying specifications (110mm multipath fibre, 110mm Class 1 PVC, 250mm Class 1 PVC, 25mm ID sensing ducts)
  • Over 4,000 hours worked with zero accidents and only 1 minor incident recorded
  • All circuits connected to National Grid substation and DC converter stations as designed
  • Site congestion successfully managed through phased construction approach
  • Programme milestones maintained despite restricted working space
  • Digital quality systems successfully implemented with real-time ITP completion and uploads
  • No impact on adjacent infrastructure or ongoing site activities
  • Works delivered to programme and quality expectations

Added Value

This project demonstrates Aaron Engineering Group’s capability to deliver critical cable infrastructure works within highly constrained site environments. Through innovative excavation sequencing, phased construction, and careful logistics planning, our teams maintained programme milestones whilst working safely within restricted working space. The implementation of digital quality management systems—enabling on-site ITP completion and direct upload to centralised logging systems—enhanced efficiency and traceability whilst supporting the paperless site management commitment. The combination of controlled excavation practices, careful sequencing, and phased construction approaches ensured safe working practices were maintained throughout, protecting both our workforce and surrounding infrastructure. The successful delivery of over 4,000 hours of work with zero accidents, coupled with full compliance to EGL2 programme requirements, demonstrates Aaron’s commitment to safe, efficient, and quality delivery on this nationally significant energy infrastructure project.