Which materials are acceptable for the grounding wire mesh?

• A. Aluminum
• B. Bronze
• C. Copper, tinned copper, or stainless steel
• D. Steel

Answer: (C)

Grounding mesh needs a path to earth that stays low in resistance and lasts in real-world conditions. Copper has the best electrical conductivity among common metals, so it provides a reliable, low-resistance grounding path. Tinned copper adds a protective tin coating that helps prevent corrosion in damp or harsh environments, keeping connections and conductivity stable over time. Stainless steel offers excellent corrosion resistance and good durability in challenging environments, making it a solid choice when exposure to moisture or salt is a concern. Together, these materials maintain electrical continuity and long-term reliability, which is why they are specified as acceptable for grounding wire mesh.

Aluminum is generally avoided for grounding mesh because its oxide layer can increase resistance and it can suffer galvanic corrosion when in contact with other metals. Bronze, while corrosion-resistant, does not match copper’s conductivity and is less common for primary grounding paths. Steel tends to rust and degrade unless heavily protected, which can jeopardize the grounding system.