The electrical hazard of the future
This paper calls attention to a continuing and growing problem concerning an ever-present electrical hazard that is being swept under the rug. Several miscalculations and lack of understanding of grounding have combined over the past 80 years to set into motion the electrocution of dairy cows, pigs and humans residing in North America from the electrical distribution system. The urge to reduce costs by the utility companies has resulted in the lack of maintenance of the electrical distribution system. This combined with an expected increase in peak demand of 16 percent over the next decade is expected to result in an increase in stray current flowing uncontrolled over the earth shocking and killing not only dairy cows and pigs, but humans too.
Equipotential Planes, a Figment of the Imagination
This paper challenges conventional established practice and presently accepted standards concerning equipotential planes. The concepts, ideas and recommendations contained within this paper are the opinions of the author. It is the opinion of the author that it is unfortunate that in the United States the vast majority of utilities use the hazardous multigrounded neutral electrical distribution system. This type of electrical distribution system uses the earth for a partial electrical neutral return path for the dangerous high voltage distribution current. The correct term for this uncontrolled current is "stray current" as opposed to the incorrect term, stray voltage, commonly used. Robert Gustafson was editor of Chapter 4, Mitigation, in the document titled, "USDA agriculture handbook no. 696, effects of electrical voltage/current on farm animals" known as the Agriculture Red Book, where he presents "various solutions to stray or neutral-to-earth voltage problems". One of his major suggestions is the installation of an equipotential plane. This paper relates testing that suggests that such a solution is harmful not only to animals such as cows and pigs, but also to humans. With the flow of stray neutral distribution current over and through the earth, one must consider the effects that this dangerous stray neutral distribution current have on an equipotential plane. According to the National Fire Protection Association's (NFPA) Standard 70, the National Electrical Code (NEC) Articles 547 and 680, equipotential planes "... prevent a difference in voltage from developing within the plane." This paper discusses the contradictions, inconsistencies and incompatibilities of equipotential planes, Ohms law and the NEC. For years it has been opined that with detailed understanding, and the correct application of Ohms law, one would come to the conclusion that the concept of equipotential planes was not only potentially dangerous, but also blatantly false. In December 2004, tests were conducted that finally confirmed that the concept of equipotential planes is a figment of the imagination
High resistance grounding of low voltage systems: a standard for the petroleum and chemical industry
A debate has existed in the petroleum and chemical industry for years concerning the grounding of LV (480-600 V) power systems. Since reliability and continuity of service are important in the petrochemical industry, some engineers in the past preferred using an ungrounded system. The practicality of such ungrounded systems becomes questionable as the size and extent of coverage increases. This paper begins with a brief history of low voltage grounding which includes ungrounded, solidly grounded and resistance grounded systems. As part this discussion, benefits and limitations of each system are covered. Reliability, continuity of service and personnel safety are important issues and are discussed. It is shown that the use of high resistance grounded LV power systems makes good sense in the petrochemical industry. Design, construction, operation and maintenance factors for high resistance grounded power systems are discussed and analyzed. The use of a high resistance grounded power system when three-phase, four-wire loads are present is discussed, Finally, operational problems and solutions are discussed where significant variable speed drive loads are utilized. The use of a high-resistance grounded power system provides so many benefits that it should become a standard of the industry, and the solidly grounded power system should be used only in applications where the high resistance grounded system becomes impractical.