The Severn-Wye Cable Tunnel, also known as the Severn Cable Tunnel, carries high-voltage (400 kV) electricity transmission lines beneath the estuaries of the River Severn and River Wye between Newhouse (Mathern), Monmouthshire and Aust, South Gloucestershire.
[1] The CEGB intended the line to Melksham substation to cross the River Severn at Sharpness using overhead cables.
The principal objection was to the impact of the power lines on the scenery of the Cotswolds and of the Vale of Berkeley.
At full power (2,600 MVA for each circuit) the cable joints are cooled by circulating oil through the hollow conductors.
[8] A powered trolley to move equipment, and in an emergency injured personnel, is provided in the tunnel.