Practical approaches to mitigating arc flash exposure in Europe

Increasing number of electrical system operators in Europe realize that the existing standards for built-in equipment safety are not enough to prevent arc flash hazards. The newest revisions of local standards for operating an electrical installation, such as the Dutch NEN 3140, (based on EN 50110) are starting to provide guidance to reduce arc flash hazards. Not all equipment in the field meets the latest standards, moreover Internal Arc Classification (IAC) does not consider risks associated with normal maintenance practices such as trouble shooting, testing and verification of de-energized state of the electrical equipment. Arc Flash Hazard calculations can conveniently quantify the potential risk and show that excessive high arc flash incident energy necessitates de-energizing of the equipment before maintenance can be performed. Yet, this is not always acceptable to plant operations. This paper will address various approaches to significantly lowering the probability of an arc flash incident and ways to limit the consequences by system design, equipment modifications and alternate protection settings and work methods. It will also discuss strategies to deal with personal protection equipment (PPE).