The ultimate goal of a LP ground system is to dissipate the energy from the lightning stroke into the earth, safely and efficiently. The efficacy of the system is one in which the potential rise of the surrounding earth is minimized and the rate of potential fall from the injection point is maximized. Step and touch potentials are maintained to safe levels and an equipotential ground plane is created to ensure the safety of equipment and personnel. Equipotential bonding is used throughout the installation to eliminate damage caused by differential ground potentials. Note that the National Electric Code (NEC) requires that the grounds from all systems including, power, cable, telephone and LP be bonded together.
The LP grounding system must be robust and constructed from materials that will perform for the service life of the building or structure that it is protecting. Inductance and skin effects are the major considerations in selection of conductors, connectors and installation practices. Radials constructed of flat strip or cable, and typically embedded in a ground enhancement material, are the most effective electrodes in reducing GPR and directing lightning energy away from the point of injection. Other commonly used electrodes include ground rods, plates, and enhanced or electrolytic ground rods.
Exothermically welded connections provide the lowest inductance path for high frequency lightning surges while providing the highest level of reliability. They are mandatory for below-grade connections and reduce the concern of corrosive deterioration.