Human factors issues and the risk of high voltage equipment: Are standards sufficient to ensure safety by design?

High voltage equipment is mostly designed according to technically prescriptive standards requirements based on electrical engineering safety principles. However a more risk-based approach to standards and regulation may be advisable to enable designer and user to take an active role in establishing that their installation is inherently safe. The use of Gas Insulated Switchgear (GIS) for instance is enabling the new substation to be housed indoors and condensed into around one quarter of the space. The manufacturers argue that design improvements in GIS make it virtually "maintenance free", comply with all the relevant standards. However some of these improvements have implications for the operators that need to be taken into account. Commissioning, operational checks and inspections and the occasional maintenance interventions are activities during which the technicians need to interface with the equipment, the issues regarding the interfaces provided have been analysed to identify their relevance in the overall risk assessment of the equipment. The paper reports about a study aimed at verifying through a risk analysis the impacts that the issues related to deficit in ergonomic design may present for the overall availability and safety of the plant. Those issues are not tackled in the technical standards and/or designers current practice.