Where shall conductors and cables be located in a tunnel installation to protect them from physical damage?

Conductors and cables should be located above the tunnel floor to protect them from physical damage. Positioning electrical wiring above the floor minimizes the risk of accidental impacts from equipment, personnel, or materials that may be moved or utilized in the tunnel. This placement is critical in environments like tunnels where space is limited, and activities might involve heavy machinery or maintenance work, increasing the potential for physical damage to unprotected cables and conductors if they are at or below the floor level.

By elevating the conductors and cables, it also allows for better management of moisture and debris that can accumulate on the ground, which can lead to deterioration or electrical hazards if situated too low. This practice aligns with the safety standards and recommendations outlined in the NEC to ensure optimal protection and functionality of the electrical system.