Kentish town project [power cable laying]

During the 1990s, NGC (UK) found that some of the 275 kV cable network was nearing the end of its economic life due to the onset of reinforcing tape corrosion. Initially, it was found that one circuit in Liverpool needed to be replaced in its entirety, then in 1996, investigations concluded that several sections of the St Johns Wood-Tottenham 275 kV cable circuits would need to be replaced within 5 years. Some sections of St Johns Wood-Tottenham circuits have subsequently been replaced along the existing route where it runs in the Regents Canal towpath, however, over 2 km of cable route which needs to be replaced runs through the streets of the Kentish Town area of north London. It was clear from the outset that replacing this cable along the existing route would prove difficult and that all alternatives would need to be considered. A feasibility study was commissioned which identified four potential direct burial routes and three possible tunnel routes. The options were costed and it was judged the tunnel option offered the best long term solution. It was decided to replace one of the circuits in a 2.5 m diameter tunnel that could accommodate the second circuit if required in the future