Ground plates shall be made of what materials?

• A. Aluminum
• B. Copper or Copper-Clad Steel
• C. Steel
• D. Plastic

Answer: (B)

Ground plates are part of the earth-grounding system, and they must provide a reliable, low-impedance path to the earth while withstanding soil conditions. Copper offers excellent electrical conductivity and good corrosion resistance in many soils, which helps keep the grounding resistance stable over time. Copper-clad steel adds the strength and lower cost of steel with the conductive, corrosion-resistant outer copper layer, giving a durable, effective grounding plate for large installations.

Aluminum, while conductive, tends to corrode in soil and can develop issues with galvanic contact to other metals, leading to higher or unstable ground resistance. Steel alone, though strong, does not achieve the same low resistance to earth as copper and is more prone to corrosion without protective coatings. Plastic is non-conductive, so it cannot serve as a grounding plate. Hence, copper or copper-clad steel is specified for ground plates.