IEEE Issues Guide to Address Electric Shock Incidents
Utilities can now use a new guide to respond to electric shock incidents.
Many of these incidents occur at swimming pools, dairy farms, and locations with exposed metal. They are usually the result of exposure to stray voltage or contact voltage when people or animals physically contact energized objects or surfaces.
In 2016, IEEE published a guide that defines stray voltage and contact voltage, and outlines standard detection, measurement, and mitigation practices that utilities can use when they address electric shock incidents. It’s the result of a 10-year collaboration among utilities, equipment providers, and EPRI, with EPRI research helping to define the characteristics and expected magnitude of stray and contact voltage for different types of objects and surfaces.
There is almost always some measurable voltage in areas near utility- and customer-operated electrical systems, even with proper wiring and grounding. While such a trace voltage is usually very low and imperceptible to people and animals, certain exposure conditions can lead to higher voltage, perceptible electric shocks, and potential safety hazards. Two familiar examples are water troughs in dairies and wet concrete around swimming pools constructed with inadequate equipotential bonding.
To support the guide’s development, EPRI built a full-size swimming pool at its Lenox, Massachusetts facility to demonstrate the effects of various bonding, grounding, and pool construction practices.
“The guide is the result of contributions from experts throughout the industry and will be a tremendous resource for utility engineers and field crews in dealing with stray voltage and contact voltage issues,” said Doug Dorr, an EPRI program manager who participated in the guide’s development.