At EC&M magazine, we receive hundreds of new product press releases, news briefs, and article pitches every month. Sorting through all of this information to determine what might be of interest to our diverse readership — which includes electrical contractors, electrical engineers, and plant facility personnel from a broad spectrum of vertical market segments — is definitely challenging. Certain categories like electrical safety and the National Electrical Code are obvious choices. These topics will likely appeal to the majority of our audience despite their specific discipline or years of experience in the industry. Others, however, are a little more niche. When the cover story for this month, starting on page 26, came across my desk, I knew this topic would appeal to electrical professionals everywhere. Not only does it help educate the industry as a whole, but it also aims to prevent similar electrical hazards from existing in the future. Written by Mark Voigtsberger, president of Florida-based Utility Testing and Geographic Information Systems, this article reveals why special precautions may be necessary when using water infrastructure as a qualified reference ground for contact voltage measurements.
IEEE 1695-2016, Guide to Understanding, Diagnosing and Mitigating Stray and Contact Voltage, addresses voltage conditions that may arise at publicly and privately accessible locations as a result of the delivery and use of electrical energy. According to Voigtsberger, “contact voltage,” which is the result of a localized electrical wiring fault, should not be confused with “stray voltage,” which often impacts agricultural applications. The IEEE Stray and Contact Voltage Working Group, which was formed at the joint request of the PES Distribution Subcommittee members and the EEI T&D Committee (and is responsible for maintaining and updating IEEE 1695), has set forth the following working definitions for these two concepts:
• Stray voltage: A voltage resulting from the normal delivery or use of electricity that may be present between two conductive surfaces that can be simultaneously contacted by members of the general public or animals. Stray voltage is not related to electrical faults.
• Contact voltage: A voltage resulting from electrical faults which may be present between two conductive surfaces that can be simultaneously contacted by members of the general public or animals. Contact voltage can exist at levels that may be hazardous.
Detecting electrical hazards (uncontrolled electricity) on publicly accessible surfaces of city streets and sidewalks is a serious concern. Municipalities and utilities try to seek out these voltages preemptively in a proactive manner rather than waiting for the report of persons or pets being shocked to materialize. The cover story, “Contact Voltage Testing: Tricks of the Trade,” examines an incident in which 237 contact voltages were reported in a relatively small area over a period of nine testing cycles. It was the proper application of IEEE 1695-2016 that identified the “qualified” reference ground being used to take the voltage readings was itself energized, contributing to the large number of reported contact voltages.
“Once a suspected energized object is identified, accurate measurements must be taken to confirm or deny the presence of a voltage potential on the object under test,” writes Voigtsberger in the article. “The practice of using water system piping or components as a qualified reference ground is common, but the case study presented here shows the pitfalls of using those items.”
Read the full article for lessons learned as well as real-world tips on how to pinpoint the actual location of electrical faults.
