A Concrete Idea [History]

The purpose of the National Electrical Code (NEC) is "the practical safeguarding of persons and property from hazards arising from the use of electricity." In establishing a ground system for industrial and commercial buildings before 1968, the NEC advocated employing and using multiple driven ground rods connected to a metallic underground water piping system when present as the main grounding electrode for the protection of the electric installations. A.G. Clark of Los Angeles presented a paper to the American Water Works Association on 26 October 1960, "Grounding of Electric Services to Water Piping Systems," which emphasized his personal experience and frustration in attempting to obtain fewer than 10 _ for each driven ground rod before tying them to the water piping system to establish a minimum resistance to the earth. Surely, there must be a better method for providing a low-resistance ground free from the requirement to connect it to the water piping system, and so my story unfolds.