National Grid Cable Tunnel

  • Sector:Energy
  • Client:Costain/Skanska Joint Venture
  • Location:London
  • Value:£1.3m

National Grid supplies electricity through transmission networks, operating at 400kV and 275kV which connects to the three substations at Hackney, St John’s Wood and Willesden to supply points where power is fed into the local distribution system.

Within London, a network of 275kV cables were installed in the 1960’s which needed replacing, as they had reached the end of their technical life. Due to increasing electricity demands, the cables were upgraded and replaced with 400kV cables which were installed within a deep level tunnel.