Cable link box identification for safe inspection and test access

Abstract

There are various approved methods for positively identifying underground cables prior to working on the cable remote from its nominated isolation point. However, identification of the cable screen when run separate to the cable core, as is the case with fully cross bonded cables routing through link boxes, is not well defined. When multiple cable screens share a common cross-linking pit, misidentification of cable screens could lead to a dangerous situation, particularly if in-service cable screens are inadvertently earthed, short-circuited or open-circuited. There are various industry accepted methods for cable identification and it is necessary to match the appropriate identification method with the type of cable installed to provide a positive identification prior to working on the cable or cable link box. The DC injection method has proven to be a reliable method for identifying single core cables but is not widely practised throughout the electrical industry.