The North Wessex Downs Visual Impact Provision (VIP) project is a flagship National Grid initiative to reduce the visual impact of high-voltage transmission lines in Areas of Outstanding Natural Beauty (AONB). Delivered by Balfour Beatty, the project involved replacing sections of overhead line with underground HV cabling.
To protect these high-voltage cables across the sensitive chalk landscapes of the Wessex Downs, we supplied ENA TS 12-24 C1+ ClearDuct beadless ducting — a compliant, durable, and installation-friendly solution that ensured both technical reliability and environmental care.
The Challenge
National Grid faced a unique challenge:
Visual impact – Overhead pylons and conductors significantly affected the protected landscapes of the North Wessex Downs AONB. Removing them was central to the VIP project’s mission.
Challenging ground conditions – The Downs consist of chalk geology and undulating rural terrain, making installation of long underground runs technically demanding.
High-voltage protection – HV cables required ducting that not only met ENA TS 12-24 C1+ specifications but also ensured long-term resilience against mechanical stress, abrasion, and moisture ingress.
Environmental sensitivity – As an AONB, works had to minimise disruption to landscapes, habitats, and local communities.
Any weakness in cable protection would compromise a nationally significant infrastructure project designed to improve both reliability and the natural environment.
Solution
We worked with Balfour Beatty to supply ENA TS 12-24 C1+ ClearDuct beadless ducting — a solution specifically engineered for HV cable protection on National Grid projects.
Key benefits delivered:
Compliance with ENA standards – fully certified to ENA TS 12-24 C1+, meeting National Grid’s technical requirements.
Beadless smooth bore – reduced pulling friction, preventing cable sheath damage and enabling longer continuous pulls across the rural route.
Durability – resistant to impact and moisture, ensuring long-term resilience in chalky, shifting ground.
Efficient installation – lightweight, flexible, and supplied in long lengths, simplifying logistics and handling across remote terrain.
Environmental alignment – fewer jointing points and quick installation minimised disturbance to the AONB.
The system enabled safe and efficient undergrounding of high-voltage circuits, forming a critical part of the VIP project. The removal of overhead lines and pylons has already transformed the landscape, preserving its natural beauty while maintaining the resilience of the UK’s electricity network.
