Application of Safety Gumboots for Construction Staff as PPE for Touch Voltage Incidents

Construction and operating staff working in and around high voltage substations and high voltage transmission systems may be exposed to unacceptable touch voltage hazards. Examples of tasks where staff may be exposed include: civil excavation in a live substation requiring removal of the insulating crushed rock layer, cable jointing, pipeline construction and repair. The removal of the crushed rock layer exposes workers to an increased chance of fibrillation under earth fault conditions. Wet or damp soil increases this risk further. Safety gumboots are made of rubber with plastic soles which could reduce this shock risk. This paper examines the insulation resistance and breakdown voltage for a range of new and used safety gumboots as an effective control measure in the shock circuit. The information from this testing is then used to build a quantified probabilistic shock risk model for resistance and withstand voltage of safety gumboots. This model is then used in a case study of a substation worker.