An earth termination system allows lightning current to dissipate into the general mass of earth through an earth electrode that is connected to the down conductor at the base of the building. The number of down conductor used is determined by the risk assessment calculation that varies depending on the building parameters, materials, height or architecture finishing.

The consequences of damage from transient overvoltages emphasize the need for a combined lightning protection solution including both structural and electronic system protection. Most modern electronic systems are at risk including personal computers, data communication networks, building management systems, security equipment, PABX systems and telephony exchanges, base stations, plant sensors, programmable logic controllers (PLCs) and even uninterruptible power supplies (UPSs). Electronic systems protection often referred to as surge protection importance is now defined in many standards, including IEC/BS EN 62305 and BS 7671.