Lightning and Lightning Protection

Lightning is the visible discharge of static electricity in clouds, from cloud to cloud or from the clouds to the earth. As advanced as we are scientifically, lightning is still not fully understood. What we currently believe is ice in a cloud forces positive charges of electricity to stay high in the cloud and negative charges to move lower. When negative charges move down from the cloud, the charges form a "pilot leader" that follows an ionized path to the earth in 150-foot steps. Once the earth is struck the lightning jumps back up following that same ionized path.

When you install a lightning protection system, you are not protecting your building from being hit by lightning, but from being damaged by providing a low resistance path for the lightning to follow. A typical system will consist of air terminals (lightning rods) and ground terminals, which are connected together with low resistance conductors. These conductors are usually copper or aluminum as are the other components of the system. These metals and their alloys are specified not only for their electrical conductivity, but also for their corrosion resistance. Additionally, lightning protection codes require separately grounded systems to be bonded together as well as other metallic items that may provide a short circuit path between grounded items. A properly installed system will also consider the many electrical devices we use in our homes or businesses. Transient voltage surge protection should be provided to keep electrical charges from entering the building through the electrical system, cable television, telephone or data lines.

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