What is a Lightning Protection System?

A lightning protection system is a passive means of preventing property damage from the effects of a lightning strike. It works by providing the electric charge produced by the clouds a path of least resistance to the ground. There are four main parts of a properly installed lightning protection system: copper air terminals, copper cable, copper clad ground rods, surge suppressors.

The air terminals and cable are typically copper, but sometimes they can (or must) be aluminum. All of the air terminals are connected via the cable which has a minimum of two ground rods buried 10 feet below grade. This system is then grounded to both the water pipes and existing ground of the circuit box. The surge suppressor can be connected to the breaker box to cover the entire electric system or they can be placed at individual appliances or electronics.

When most people hear the term lightning rod, they picture large ornate rods with heavy cable draped on the roof and down the sides of old homes (see fig. 1). LSV tries to make the lightning protection system as inconspicuous as possible.

Typically, the only things visible on a lightning protection system are the air terminals, 10"-12" copper rods, on the chimney and roof ridges. If the system is to be installed on an existing building, every effort is made to conceal the copper cable (see fig. 2).

If the copper cable cannot be concealed, the cable will be less noticeable as it weathers and changes from shiny orange to dull patina (see fig.3). Whether a lightning protection system is concealed during construction of a new building or exposed on an existing structure, the materials used are identical.

Lightning protection systems can be installed on a variety of structures including homes, businesses, farm buildings, boats, and trees to protect them from damage. There are several independent organizations that have issued standards on the installation and design of lightning protection systems. The three most recognized are Underwriters Laboratory (UL), Lightning Protection Institute (LPI), and National Fire Protection Association (NFPA). Fore more detailed information on the standards you can contact any of the organizations and ask for a copy of UL96A, LPI-175, or NFPA-780, respectively.