Lightning rod; photo by Der Unfassbare/Wikimedia Commons
Lightning strikes are essentially extreme electrically charged emissions. A lightning rod attracts the lightning strike away from other portions of the house. The electricity of lightning obeys the same laws of physics as other electrical occurrences. Therefore, the electricity readily travels through the rod into the ground via a conducting cable.
Cable connected to the lightning rod; photo by Der Unfassbare/Wikimedia Commons
Lightning rods made of aluminum or copper are installed on the house's roof. Depending on the size of the property, more than one lightning rod may need to be installed. Usually the best place for lightning rod installation is the highest point of the roof. The lightning rod is connected to a lead wire made of copper or aluminum. When lightning strikes the lightning rod, the energy is safely routed into the ground via the attached cable.
Rudimentary rod/cable/grounding setup; photo by Pearson Scott Foresman/Wikimedia Commons
When the lightning strike is attracted by the lightning rod and the electricity sent into the ground via the attached cable, the presence of ground rods allows for the safe dispersion of the electrical charge in the ground. Failure to provide adequate grounding results in lightning damage not to the top of the house, but instead to the side, its foundation, or an adjacent property. Since soil conditions vary greatly, manufacturers have devised a wide variety of grounding systems that work for virtually any situation.
Historic lightning rod system installation requirements; by J.A.H. Reimarus/Wikimedia Commons
Too many hobbyists are trying to install lightning rods, cables and grounding rods without realizing that in some cases they are doing little more than investing in a false sense of security. It is imperative that all components of the lightning protection system are UL labeled and brand new. Since lightning strikes carry huge bouts of electricity, only system components specifically manufactured to accommodate this kind of charge can safely divert it away from the home. If you are a do-it-yourselfer, it is worthwhile to read the system requirements as outlined by the Independent Protection Company (a link is listed in the resources section).
