![]() ![]() Cost is usually between $2,500 and $4,500. ![]() Have a system installed by a UL-certified installer, whose work must pass third-party inspection. ![]() Wires and cables may have outdated or inadequate surge protectors, grounding systems may need updating…but general electricians may not be experienced in lightning protection requirements. Roofers, chimney masons, and house painters may disconnect cables and connectors and forget to reattach them in your contracts, specify a mandatory inspection by a UL-certified inspector. Regular inspection is the key to safe functioning. Keep aluminum components away from copper roofing or gutters. To avoid oxidation and even fire, don’t mix copper and aluminum components thus, don’t use a copper rod with aluminum roofing or siding. A braided copper or aluminum cable made for lightning systems connects the rods and runs into the ground to dissipate a charge. Rods at least 1o” higher than the structure are placed at intervals along high points such as the roof crest, ridge, chimney, or along the perimeter of a flat roof. Today’s rods are usually made of aluminum or copper a pointed Franklin rod looks historically correct. Today’s rods are called “air terminals,” and they’re accompanied by bonding conductors and cables connecting them and running to the ground, along with two or more grounding rods or plates in the earth. King George III had his palace equipped with blunted rods, but Americans stuck with the pointy ones, which was taken as a sign of their bad attitude.) British scientists maintained that a rod topped with a ball was better. (Turned out that Franklin’s pointy design had problems, as it tended to ionize the air, making it conductive and thus a strike more likely. The lightning’s path from storm clouds was thus facilitated (though neither directly attracted nor repelled), deflecting it away from the structure, into the rod, and then down a low-resistance brass wire to the earth. The Franklin Rods were simple: a pointed iron spike 8′ to 10′ tall with a gilded tip (to prevent rust), fastened to the highest point of a building. Church spires used to be the highest point in a town, so pragmatic pastors told congregants to stay away, not come to pray, during thunderstorms. The height of the building is an important consideration. During a storm, it’s dangerous to be near a filled sink or bathtub, and to stand too close to conductive metal, like a stove. The high heat of the strike can flash-steam water, causing an explosion (it’s why trees shatter when hit). Patriotically, he refused to patent his invention, and by the 1760s lightning rods were marketed throughout the Colonies.Ī lightning strike can not only start a fire but also blow apart even masonry, and may injure or electrocute indoor occupants. Lightning rods are an American invention, thanks to Benjamin Franklin’s 1740s experiments with electricity. A lightning rod on the tower of the author’s house. ![]()
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