This report documents a range of hazards associated with utility work in confined spaces that contain energized transmission cables. The report has been prepared in response to concerns expressed by members of the Transmission Underground Cable Interest Group (TUCIG) regarding hazard management in these situations. The objective of the report is to identify the major risk factors for workers entering confined spaces containing energized transmission cables using published information on the reliability of transmission cables. A review of some cable system failures inside confined spaces is presented and the underlying mechanisms noted. The results of a survey of existing utility practices are compared, and this information is used in developing a methodology for performing risk assessments for the different types of transmission cable commonly used together with various work activities and environments. This is expected to be a practical tool for use by utilities in arriving at consistent evaluations of the risks associated with work that requires proximity to energized transmission cables inside confined spaces. A number of possible risk mitigation methods and technologies are reviewed. Conclusions are presented and recommendations are made for areas of further work.
Keywords: Confined Space, Manhole, Tunnel, Transmission Cable Failure, Transmission Joint Failure, Worker Safety