What grid size is specified for the grounding wire mesh?

• A. 1-2 inch squares
• B. 2-4 inch squares of #6 AWG copper, tinned copper, or stainless steel
• C. 6-8 inch squares
• D. 4-6 inch squares of aluminum

Answer: (B)

Grounding effectiveness relies on a uniform, closely spaced conductor network so every point in the area stays at the same electrical potential and the impedance path to ground remains low. In this standard, the grounding wire mesh is specified as a dense grid using relatively sturdy conductors to withstand field conditions and corrosion while carrying any fault current. The best choice specifies squares that are 2 to 4 inches on each side, made of #6 AWG copper, tinned copper, or stainless steel. This combination provides a tight mesh that keeps the maximum distance to the nearest mesh intersection small, minimizing potential differences across the area and helping ensure a reliable, low-impedance ground. The chosen conductor sizes and materials balance conductivity, durability, and corrosion resistance. Smaller squares (1-2 inches) would add cost and complexity without meaningful impedance benefits, while larger squares (6-8 inches) would reduce mesh density and raise the grounding impedance. Aluminum is not preferred here due to its different corrosion behavior and electrical characteristics in this context.