Lightning conductors concealed in steel reinforced concrete must be connected to the reinforcing steel at:

Connecting lightning conductors to the reinforcing steel at both the lower and upper extremities is essential for ensuring an effective grounding system for lightning protection. This dual connection allows for the dissipation of lightning energy throughout the entire structure, reducing the risk of damage during a lightning strike.

When connected only at the lower extremities, there could be an inadequate path for the lightning energy, potentially leading to weaknesses in certain areas of the structure. Similarly, connection solely at the upper extremities would not provide an equal distribution of forces throughout the structure, leaving parts of it vulnerable.

By establishing connections at both ends, the grounding system can effectively manage and distribute the energy from a lightning strike, ensuring the integrity of the structure and protecting against electrical surges that can cause fire hazards or structural damage. This comprehensive approach is critical to enhancing the safety and performance of the lightning protection system.