This handbook provides a comprehensive resource for the electric utility engineer to understand the sources of exposure voltages, their effects on animals and humans, techniques for field measurement and investigation procedures, and the mitigation strategies and equipment available.

NRECA members have access to this report through NRECA's partnership with the National Electric Energy Testing Research & Applications Center (NEETRAC), a utility test lab operated by Georgia Tech.

Background

With 50 years of experience, the electric utility industry has accumulated a tremendous amount of research data on this subject. Pertinent technical papers, standards, and publications are summarized and referenced in this handbook. Descriptions of the different types of distribution systems and grounding methods are also provided, as well as the fundamentals and sources of exposure voltage.

Sometimes identified as "neutral to earth voltage" or "neutral to ground voltage," "stray voltage" or "exposure voltage" is defined as the difference in potential between animal or human contact points, such as a cow's body and hooves or a child's hands and feet. This definition obscures the two-fold nature of the problem—that of identifying a source for the voltage and a path for the current. The voltage source is often hidden by a multitude of contributing factors, some endemic to the particular farm or household. Although the path taken by the current is the one of least resistance, it is not constant because of the changes in path resistances.

Approach

This 322-page handbook provides comprehensive information on all aspects of exposure voltage. Six actual case studies, provided by our NEETRAC members, are included to illustrate mitigation solutions through computer models for dairy farms, residential subdivisions, boat docks, and parallel transmission lines.

Results

Co-op staff can use this handout to further understand exposure voltage and prepare procedures to deal with it. Co-ops can also use the two pamphlets to educate members on exposure voltage and swimming pools.

Audience

Engineering & Operations staff, communicators, marketing, member services

Keywords

Engineering, operations, Exposure voltage, stray voltage, swimming pools

Documents