Blackfriars Station is a complex, Network Rail and London Underground (LUL) station interchange in the heart of London, which has recently undergone extensive redevelopment. Its Network Rail platforms have been extended and span the River Thames a short distance from Blackfriars Bridge. The north bank entrance is on Queen Victoria Street and a new entrance on the south bank was opened in December 2011. At the same time, the Underground station was closed for nearly three years (from March 2009 until February 2012) to enable major engineering works to be carried out, allowing the Network Rail and LUL lines to share the same ticket hall and other services.
Not only did Balfour Beatty (the Main Contractor) have to meet the many technical and logistical challenges associated with carrying out a fast track, major construction project in central London, they also had to meet the many electrical challenges arising from an installation involving Network Rail “Third Rail” traction supplies and London Underground’s Section 12 requirements for underground stations. Fortunately, Blakley Electrics were on hand to assist!
Third Rail Locations
In areas within 30 metres of the Third Rail, Network Rail specify that RCDs are classified “DC Immune”, as made by Blakley Electrics. Unlike standard RCDs, DC Immune RCDs are not desensitised by the presence of relatively small DC leakage currents, which saturate the magnetic circuit of standard RCDs and prevents them from tripping. DC Immune RCDs normally protect single ring main circuits. However, due to the high number of circuits to be protected and the tight space constraints, multi-way, DP, DC Immune RCD assemblies were supplied.
DC Immune RCDs in LUL Section 12 Locations
Due to the integration of Network Rail and London Underground lines, some products had to meet the requirements of both rail companies. This resulted in the incorporation of DC immune RCDs in our TDC series of combined transformer and distribution cubicle. The TDC is used widely within LUL installations to feed Unmanned Ticketing Systems, Platform Sockets and other 110V supplies but, due to the proximity of the Network Rail “Third Rail”, DC Immune RCDs had to be incorporated. Transformers with integral, 16A metal socket outlets (as used in LUL installations), also had to be equipped with Network Rail approved DC Immune RCDs.
In addition to a wide range of equipment required for permanent installation within the new station, we were also able to draw on our experience of manufacturing equipment for construction sites and supplied Balfour Beatty with Mains Distribution Assemblies, Site Transformers and 110V lighting equipment, to power and light the site throughout the project, all in accordance with Section 704 of BS7671 and BS7375.
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