Surge Protection Exterior Ground Quality and Bonding

The foundation of an effective surge protection strategy is a well-designed and tested exterior grounding system to which all other grounding systems (e.g., tower, building, cable, phone, electric, and perimeter exposures) are effectively bonded.  During our review, it was unclear if the quality of the current grounding system had ever been evaluated to ensure it provides a low impedance path to ground and it was undetermined if the tower ground and other grounding system are bonded to it.  Typically, a well-designed ground system will include a soil analysis to determine soil resistivity, and then the type, number and placement of ground rods are determined to provide a low impedance ground that allows for rapid dissipation of lightning-sized surges.  Bonding of external grounding conductors is normally done by an exothermic weld process to fuse the metals together and avoid problems of corrosion that can reduce grounding efficiency, and ground rods and connections are typically below grade (usually below the frost line) to avoid physical damage and the problems of expansion and contraction.  Due to the fact we could not verify these elements with your current system, we recommend your organization consider having a lightning protection company or similarly qualified service agency evaluate the current system design to assure it will provide you with the necessary grounding performance.