National Grid to upgrade crucial overhead electricity transmission line in the south of England
- Overhead lines spanning 40km north of New Forest National Park to be refurbished as part of ongoing investment in the region’s electricity network.
- Massive 120-tonne supergrid transformer also safely delivered to Mannington as part of separate substation project.
- No disruption to electricity supplies anticipated during the works.
National Grid is set to begin a major programme of refurbishment works on its overhead electricity transmission lines between Mannington substation in East Dorset and Nursling substation in Southampton in the coming weeks.
Work will take place between June and November 2026 and involves reconductoring – or replacing with newer wires – the existing overhead lines spanning the 40km route’s 115 pylons, as well as refurbishing the steel structures and fittings.
Following an earlier phase of the project in 2022–2023, the scheme will now see the remaining sections of the route upgraded to ensure the continued safe and reliable operation of a key part of the network that powers homes and businesses in the south of England.
Balfour Beatty is carrying out the works on behalf of National Grid, with preparatory activity already underway to establish temporary access routes and ready each pylon site ahead of the works kicking off.
The refurbishment forms part of National Grid’s wider programme of investment in maintaining and upgrading its transmission infrastructure across England and Wales, and will enhance network resilience and help futureproof electricity supplies in the region as demand grows.
Stephen Fedzin, senior project manager at National Grid, said:
This overhead line has been reliably transmitting power across the region for decades, and our upgrades will help ensure it continues to operate safely. It’s all part of our nationwide programme of work to maintain and develop vital infrastructure so it can keep delivering electricity to communities long into the future.
As part of a separate set of works at Mannington substation, a 120-tonne supergrid transformer – a weight equivalent to 20 African elephants – was delivered to the site from Poole Harbour over the weekend. The massive unit was delivered by specialist hauliers on Saturday, safely navigating its 37km journey under police escort.