Understanding nuisance shocking from an electric power utility perspective

Nuisance Shocking—the unpleasant sensation that a person or animal can experience when they inadvertently get between an energized point and ground can be something of a mystery. Stories are told of cows that won’t give milk, dogs that bark out in the yard whenever the phone rings, and people getting an unusual “wake up call” when they step into their hot tub or back-yard pool. However, despite the esoteric nature of nuisance shocking, the science necessary for understanding it and mitigating it has advanced significantly in recent years. Also, the various mechanisms that can lead to nuisance shocking are now better recognized. Contact voltage, stray voltage, elevated neutral-to-earth voltage, and metallic object-to-earth voltage, are some of the unique terms used to describe nuisance shocking. This paper provides a brief history of the phenomenon of nuisance shocking with several case studies. In addition, this paper also examines the techniques for diagnosing nuisance shocking problems and follows with a discussion of the traditional techniques for mitigating nuisance shocking problems.