Measurement of grounding resistance over a seasonal cycle with hygroscopic materials in the encapsulation of grounding rods

Abstract

This paper evaluates the feasibility of using hygroscopic lightweight structural concrete (LSC) materials in electrical grounding systems to reduce grounding resistance and apparent soil resistivity across seasonal variations. Laboratory and field experiments monitored the grounding resistance of rods encapsulated with LSC materials, composed of vermiculite, clay, sawdust, and cement, compared to unencapsulated systems. The results indicate an average reduction of to 40% in grounding resistance and 20% in apparent soil resistivity for encapsulated systems, even in soils with resistivity up to . Encapsulated rods demonstrated superior performance in single-rod and three-rod inline systems, commonly used in practical applications, with seasonal variations controlled within 15%. This study highlights the application of LSC materials, traditionally used in civil engineering, as grounding enhancement materials, offering improved seasonal stability and efficiency in high-resistivity soils, while presenting a technically and economically viable alternative to enhance the reliability of electrical grounding systems.