55 It’s Farming. And It’s Better. Better Farming | November 2024 LIGHTNING ROD SYSTEMS FOR FARMS The evolution of wiring in lightning protection. By Ralph Winfield Lightning is a rapid discharge of energy between clouds and the ground. Lightning can and does strike the high point of buildings and other structures. The pointed lightning rod on the top of the CN Tower in Toronto can and does attract many lightning strikes. Early wooden sailing ships on the high seas were also very vulnerable to lightning strikes because of the tall masts. Lightning strikes can cause fires if the lightning rods are not effectively grounded. Lightning rods allow the lightning strike to take the path of least resistance and send it to the ground. If grounded, the lightning rod systems should literally take the high-voltage strike to the ground. (Of course, there are some exceptions based on soils such as dry sand or bedrock.) Older wooden barns and houses were and still are vulnerable to lightning strikes. Steel-framed buildings, however, usually have structural members connected directly to the ground to provide lightning protection. Overhead electrical wires between farm structures are also vulnerable to lightning strikes and wind damage. Most older barns were made almost entirely of wood but might have a steel roof. The dry contents – normally hay or straw – made them especially vulnerable to fire. Many of those older two-storey barns had lightning rod systems installed (some with multiple matching rods interconnected by a cable) to draw off the electrical charge and direct it to the ground nearby using a copper conductor and a driven ground rod. Copper used to be the wire of choice until the price of copper went up, which brought on the use of aluminum wiring in houses. Aluminum was never used in barns housing livestock because of the corrosive nature of the air. When my in-laws built their home at the farm down the road, I was working for Ontario Hydro and cautioned them against aluminum wiring because it did not have the same high conductivity as copper. My childhood home farm in West Montrose had lightning rods installed well before my time on both the house and barn. The farm didn’t sell when all the farm cattle and machinery were initially put up for sale, so my widowed mother stayed there for another two years. When it was finally sold, the buyers insisted that the lightning rods be removed as soon as they took it over. They were not opposed for any technical reasons but, rather, religious beliefs. Glass balls were often used on lightning rods to increase aesthetics. I remember the glass balls on lightning rods on the house at my wife’s home farm. One was on a taller stand because the rod had to be higher than the chimney. When we switched to a metal roof, the lightning rods were removed. How it Works A vintage glass ball on a lightning rod stem salvaged from the home farm. Ralph Winfield photo
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