Reasons for Using Lightning Rods

Lightning rods are simple in design and yet can protect against dangerous weather efficiently. Without lightning rods, the damage to tall structures would be immense. Skyscrapers, radio towers and broadcast antennas all need lightning rods to avoid damage in storms. Lightning rods also protect smaller structures like houses from the significant danger posed by lightning.

Function

• During a lightning storm, charged ions in the clouds accumulate and begin to reach toward the ground for a release path. This attracts oppositely charged ions at ground level, which concentrate at sharply pointed ridges. The point of a lightning rod, made of highly conductive material, provides the easiest path for these ions. When enough ions accumulate to allow for a strike, the resulting lightning follows this easiest path to the lightning rod. The rod then conducts the electricity to a grounding point via conductive wiring. The electricity dissipates upon reaching the ground.

History

• The lightning rod was an 18th-century invention of Benjamin Franklin. In 1750, he first described the lightning rod as an 8-to-10-foot iron pole attached to the roof of a building. Following experiments that proved lightning was a form of electricity, Franklin began to advocate that long, pointed iron stakes be affixed to the roofs of tall buildings. Even within Franklin's lifetime, many such lightning rods came into use. The basic design for lightning rods remains the same today.

Benefits

• Despite the saying, lightning does strike twice. Tall buildings can receive dozens or even hundreds of lightning strikes over the course of a year, with multiple strikes possible during single storms. Without a lightning rod, each of these strikes could cause damage, electrocution or fires. Modern skyscrapers depend on lightning rods. Lower buildings and private homes also benefit from lightning rods, especially if the roof of the structure is the highest point in the surrounding area. With fire a likely result of even a single lightning strike, you should have a system to redirect lightning away from the house.

Considerations

• A lightning rod does not work without a good location to ground the charge hitting the rod. You should ground all lightning rods in the soil, preferably soil that is moist and filled with electrolytes. If you do not have a good grounding location, electricity has more opportunity to spread from the original grounding site and affect more area.

Geography

• Some parts of the world are more prone to lightning strikes than others. Regions with higher instances of thunderstorms need more protection than areas with little lightning. In the United States, lightning strikes with the greatest frequency in the southern, eastern and central parts of the country. Lightning is also a seasonal threat in desert areas like the Southwest. Buildings in lighting-prone areas should always have lightning rods.