– how does a 2ft lighting rod make a house safer?


Most houses I’ve looked at don’t even have them (at least visibly) but I’ve seen them on office buildings. Doesn’t the lightning still burn the house/area the rod is attached to?

In: 1

The rod is made of a highly conducting material like copper. The rod is attached to wire to take it to ground. Usually there are more than one wires. This is what makes it safe is the wire giving a safe path to ground. Sometimes the wires become disconnected, and it can then cause fires when hit

Lightning rods are typically isolated from the house and direct the current into the ground, they are also *much much much* more attractive for lighting than anything else on the home (ideally) to strike. The lightning wants to go the Earth anyway, it can either stay in the highly-conductive rod/wire or leave the wire and enter wood/brick/drywall on the house. Why would it leave the rod/wire? Think of lightning like an obese midwesterner and the rod is lobster at the all you can eat buffet. It’s *that* appealing, ain’t no one saving room for the steamed asparagus.

Anywho, yes, there might be some damage to the structure but these components are somewhat sacrificial, you don’t really care if there are some little melting or burns where the tiebacks connect to masonry, but it’s unlikely enough to cause a structure fire.

The lightning rod is connected to a wire and the wire is connected to the ground. This gives the lightning a good, predictable path to the ground.

Physics is what it is, and there can certainly be circumstances where the lightning heats the rod/wire enough to start a fire. In general the materials and installation are done to try and prevent this from happening, but every now and then nature really does something extraordinary like striking the rod 3 times in a row very quickly. We can’t plan for everything.

The lightning rod’s biggest value is making it extremely likely that IF lightning strikes near the building it strikes a thing we’ve built that is designed to direct all that energy along a predictable path in a safe way. Without it, lightning strikes somewhere unpredictable and takes an unpredictable path to the ground. That means a lot of energy goes through things that weren’t designed for it and, usually, a lot of damage happens.

So like a lot of other “safety” things, it doesn’t mean buildings with lightning rods *never* take damage or catch fire. But the ones with lightning rods catch fire or take damage so much less frequently the lightning rod setup usually pays for itself many times over. Think about it like fire sprinklers: they don’t STOP fires from happening. They only work after the fire starts, and often the water does damage to the building. The hope is they stop the fire quickly enough the water damage is less severe than the fire would have been. Lightning rods have the same idea. We’re hoping that if lightning strikes a thing with a wire to the ground, the damage that does costs a lot less and is safer than if lightning struck somewhere else.