If a copper grid is used for equipotential bonding, how deep below finished grade must it be secured?

When using a copper grid for equipotential bonding, the National Electrical Code specifies that it should be secured at a depth of 6 inches below finished grade. This requirement ensures that the bonding grid is adequately buried to prevent physical interference and to maintain the integrity of the grounding system. A consistent depth helps to protect the copper grid from potential corrosion caused by soil contact and ensures that it remains effective in providing a low-resistance connection for fault currents.

The specifications for this depth are also influenced by the need for safety, as a properly installed equipotential bonding system mitigates the risk of electrical shock in aquatic environments, such as swimming pools or spas. Maintaining the grid below ground level ensures it is less likely to be disturbed during surface activities and provides a more stable grounding reference.

Thus, the correct choice of 6 inches aligns with NEC guidelines, reinforcing the importance of proper installation practices in enhancing safety in electrical systems associated with body of water installations.