Mendip Hills

Overview – Winter 2022

In December 2021, National Grid’s contractor, Balfour Beatty, completed the installation of high voltage, 400kV cables under the Mendip Hills AONB. In total, the team has pulled 102 kilometres of cable (the distance between Bridgwater and Gloucester) since the work begun in  February 2021.

Work now continues with joining and testing the cables, ahead of energising the cables later in 2022.  Full reinstatement and completion of the underground works is expected by 2024.

Once the new cable is energised and the existing 37 kilometres of existing 132,000 volt pylons owned by Western Power Distribution (WPD) between Bridgwater and Sandford are removed, this will be the first time that this area of the Mendip Hills has been pylon-free since the 1960s.

National Grid started to remove WPD’s pylons in 2021. This work is part of the changes we’re making to WPD’s network that’ll see 67 kilometres of existing overhead line, including 249 pylons removed by 2025, to make way for and reduce the visual impact of the new T-pylons.

We recognise that our construction activity impacts local communities and work with our contractors to limit that as much as possible.

Contact our community relations team to register for project updates direct to your inbox.

Take a look at our detail map

Projects timeline

Early 2019 to early 2024


Build Mendip Hills 400,000 volt underground cable

Work started in this area in April 2019.

What we're doing:

  • Advance landscaping and planting around the location of the new cable sealing end (CSE) compound.

  • Building temporary entrances and access roads to allow construction traffic to enter site from the local highway. You can find more information on our construction information page.

  • Installing a temporary site office and temporary construction compound north of Tarnock, and up to four secondary temporary construction compounds along the route to minimise traffic movements on site. One of these secondary compounds will be located immediately south of the new CSE compound.

  • Constructing a new CSE compound east of the M5 motorway to the south of the Mendip Hills Area of Outstanding Natural Beauty (AONB) and the River Axe.

  • Laying 8.5 km of 400,000 volt underground cables from the CSE compound south of the Mendip Hills AONB northwards to the new Sandford substation.

Mid 2021 to mid 2022


Remove existing 132,000 volt overhead line

What we're doing:

  • Removing Western Power Distribution’s overhead line from Bridgwater Substation to the A368 in Sandford. This will make way for, and minimise the visual impact of the new overhead line.