Wires will be replaced by Balfour Beatty on behalf of National Grid on a 40km section of the electricity transmission network, covering 115 pylons, between Mannington substation in East Dorset and Nursling substation in Southampton.
The company said the wires would be replaced under “a major programme of refurbishment works on its overhead electricity transmission lines” between June and November 2026.
The works involve “reconductoring”, which means replacing with newer wires, and will also see the steel structures and fittings being refurbished.
During the course of the work, National Grid said it expected there to be “no disruption to electricity supplies”.
The wire replacements and structure refurbishment are planned after an earlier phase was completed in 2023.
“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,” National Grid said in a statement on 26 May.
The works “will enhance network resilience and help futureproof electricity supplies in the region as demand grows”, the company added.
National Grid senior project manager Stephen Fedzin 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.”
Separately, National Grid said a “massive” 120t supergrid transformer was delivered to Mannington substation from Poole Harbour.
It was delivered by “specialist hauliers” on 23 May after having navigated a 37km journey under police escort.
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