North and South 400kV Overhead Line, Avonmouth

Once complete, this £214 million project will help transmit low carbon energy to six million UK homes and businesses on behalf of National Grid.

Balfour Beatty will design, supply, install, test and commission a new overhead line which will form a critical element for the Hinkley Point C connection (HPC) scheme. Spanning 48km across the Mendip Hills in Somerset, the new 400kV overhead lines will transmit energy from Hinkley Point C new nuclear facility to Avonmouth substation.

To deliver this scheme, we bring together expertise from across Balfour Beatty including our civil engineeringpower transmission & distribution and ground engineering teams. 

Awarded through National Grid’s Overhead Line Design and Build Framework, the contract forms a vital part of the HPC scheme, linking the new nuclear reactor to the national grid.

The world’s first T-Pylons 

The project will use National Grid’s new T-Pylon design, marking the first time this technology has been used on a live transmission asset. The new T-Pylon design significantly improves efficiency, reliability and safety by vastly reducing the need for working at height. 

We are also working on the Hinkley 400kV Cable Works (Mendips) contract, a critical part of the Hinkley Point connection scheme, which will connect the new HPC reactor to the national grid. 


kilometres of overhead lines


innovative T-Pylons installed