Hinkley Connection Project completes high-voltage cable installation under the Mendip Hills

National Grid and Balfour Beatty engineers working on the Hinkley Connection Project have completed the installation of high-voltage, 400kV cables under the Mendip Hills Area of Outstanding Natural Beauty (AONB).

Since starting in February 2021, teams have pulled a total of 102km cables (the distance between Bridgwater and Gloucester). The cables were delivered on 108 separate cable drums. Each drum held approximately 1km of cable, weighed between 35-50 tonne and stood 5 metres high. Next follows a programme of jointing and testing with energisation expected in Autumn this year. Reinstatement of the land is already underway on different parts of the route.  The Mendip cables section of the Hinkley Connection Project will be fully complete by the end of 2023.

Once work is completed and existing WPD pylons removed in summer, this part of the Mendip Hills AONB will be pylon free for the first time since the 1960s. Last week, representatives from the AONB Unit visited to see the works for themselves and gain insight into what is involved in a project of this scale.


Jim Hardcastle, Manager of the Mendip Hills AONB Unit said: “Placing the cables underground clearly requires complex engineering solutions but it also reinforces the importance of the AONB status. The status recognises the Mendip Hills as one of England’s finest landscapes and loved by many people. Organisations should go above and beyond the normal levels of delivery in such a special place like this.

“The visit helped our understanding a lot so we can transfer this to others who ask us about it - especially the reinstatement after the work is completed.”

James Goode, Project Director for National Grid said: “Completion of the installation underground cables in the Mendip Hills is a huge milestone for the project, bringing us a step closer to bringing low carbon energy to 6 million homes and businesses across the UK. The project continues with construction of pylons - including the world’s first T-pylons - along the route between Hinkley Point C and Seabank substation, with completion due in 2025.

“We want to be a good neighbour and work with local charities and organisations like the Mendip Hills AONB Unit along the route of our project, supporting initiatives like Counting on Mendip and other projects.  We were delighted to welcome the AONB Unit onto site to see the works at first hand.”



Find out more about the Hinkley Connection Project at www.hinkleyconnection.co.uk.

Additional notes:

  • The distance between Loxton and Sandford is 8.5km but a total of 102km of cable has been laid.  That’s down to the design of the underground cables.  To have the same electrical capability as the 400kV overhead lines that they are connecting to, 12 cables are required. These are divided across four cable trenches, with three cables in each trench.

  • To date, National Grid has awarded over £873,000 from its Community Grant Fund to support 55 local projects in communities impacted by the route.