What key element was described in Tesla’s patent intended to prevent under near-normal conditions?

Answer

The protection system itself becoming a path for dangerous electrical energy to enter the structure.

Tesla's patent description details a mechanism intended to ensure the protection system does not itself become a path for dangerous electrical energy to enter the protected structure under normal or near-normal conditions.

What key element was described in Tesla’s patent intended to prevent under near-normal conditions?
inventioninventorTeslaelectricitylightning rod