Regarding the installation of grounding systems, it is not common for the installation site to be re-located due to high soil resistivity. Enhancement materials have been widely used for their known advantages, including their ability to reduce the resistivity of soil. Although some studies have been conducted on the characterization of EMs under AC of various frequencies, limited studies can be found on their performance when mixed with various percentages of water content (WC) and soil. In this work, sand mixed with controlled percentages of enhancement materials (EM 1, EM 2 and EM 3) and controlled amounts of water content was placed on a parallel plate and tested under AC of various frequencies to obtain the resistivity and permittivity. It was found that dry sand–EM mixtures can be represented by an R-C parallel circuit, while wet sand–EM mixtures can be represented by a nonlinear R. These new test data providing the soil resistivity and permittivity of various sand–EM mixtures are important in selecting suitable EMs to be used in grounding systems.
