What must the required connection between the lightning protection system and the water system use?

The connection between the lightning protection system and the water system must utilize a main size cable conductor to ensure proper conductivity and effectiveness in dissipating electrical energy during a lightning strike. A main size cable conductor is specifically designed to handle higher currents and provides a secure and robust connection that meets safety standards.

Using a main size cable ensures that there is minimal resistance in the connection, which is critical for the lightning protection system to function properly. It helps to facilitate the quick termination of lightning strikes, directing the discharge safely into the ground and preventing damage to the structure and its occupants.

Other options, like thin wire conductors or flexible tubing, do not offer the same level of durability or capability to handle the high currents associated with lightning strikes. Similarly, a steel pipe connection may not provide the necessary electrical conductivity as effectively as a main size cable conductor, which is specifically tailored for this purpose.