FIELD TESTING OF ELECTRICAL GROUNDING RODS

A 7-year program of field testing metal rods for electrical grounding was conducted. Single rods of galvanized steel, copper-clad steel, Ni-Resist cast iron, type 302 stainless steel, type 304 stainless-clad steel, zinc, magnesium, and aluminum were tested along with couples of these to mild steel rods. Sets of both single and coupled rods were removed, cleaned, and weighed after 1, 3, and 7 (or 5) years. Potential, resistance, and current measurements were made monthly as far as practicable. Weight losses and electrical data were analyzed for correlations. It was concluded that type 302 stainless steel and type 304 stainless-clad steel rods were the best choices for general use.