Elstree to St. John's Wood Cable Tunnel

Elstree to St. John's Wood Cable Tunnel
Location
CountryUK
ProvinceGreater London
Ownership information
OwnerNational Grid plc
Construction information
Construction started2001
Commissioned2005
Technical information
TypeUnderground tunnel
Type of currentAC
Total length20 km (12 mi)
AC voltage400 kV

The Elstree to St. John's Wood Cable Tunnel, known as The London Connection during construction, is a 20 km long, 3m wide tunnel beneath northwest London. Constructed between 2001 and 2005, the tunnel carries high voltage transmission lines from Elstree substation in Hertfordshire to Lodge Road sub station in Westminster at a depth of 20m below street level.[1]

The tunnel runs beneath the A5 road for the majority of its length, and houses a single 400 kV power transmission circuit with a rated capacity of 3700 A. There is provision for a second circuit to be installed in the future.[2]

A remotely operated, battery powered monorail system runs along the tunnel, allowing the cables to be inspected remotely using infrared cameras.[3]

Route of Elstree to St John's Wood cable tunnel

References

  1. ^ "ABB starts to make 'The London Connection'" (Press release). 25 October 2004. Retrieved 13 January 2020.
  2. ^ "London extension uses biggest ever XLPE cable". Modern Power Systems. 20 April 2001. Retrieved 13 January 2020.
  3. ^ "The private monorail tunnel under North London". Ian Visits. 12 October 2016. Retrieved 13 January 2020.

51°31′34″N 0°10′19″W / 51.526°N 0.172°W / 51.526; -0.172