OT / Lightning Rods

When I was about 12, I spent a couple of weeks visiting my cousins on their farm on the plains of Eastern Montana. I noticed that all their buildings had lightning rods, but didn't think too much about it. One night we had a tremendous lightning storm that was a real show. The next morning, their herd of cows was out, so we rounded them up and put them back in and began looking for where they had got out. On top of a small hill, we found where apparently lightning had struck the barb wire fence. One steel T post was completely gone, as was about 40 or 50 feet of wire. The barb wire looked like it had been cut off with a cutting torch and there was some slag on the ground. Probably if it hadn't rained during the storm, there would have been a grass fire. My cousins and I spent the rest of the morning fixing the fence. They said that they had seen the same thing happen before, but I was pretty impressed.

Luckily, they didn't lose any stock. About 10 years later, my Dad lost 7 head of cows to lightning. They were bedded down under a pine tree that obviously got hit by lightning in a storm. We didn't find them until the next day when my Dad counted the cattle and went looking for the missing ones. Our cattle operation sure didn't make any money that year! At least we didn't have to pay to have the carcasses hauled away--the rendering company came and picked them up for free.

Lightning is something to be concerned with. Since you already have the system, it shouldn't be too much work to put it back up after reroofing. Good luck!

Lightning rods do work, provided they're reasonably well installed. Once you get past the marketing hype, the basic rods work just as well or better than any of these fancy things.

Lightning rods at the height of a house do NOT attract lightning. If you get an attachment to the rod, it would have attached to your house had the rod not been there. There is some anecdotal evidence that high structures do attrack lighting, but nothing to support any contention that something the height of a house would.

The sole purpose of a lightning rod is to minimize the chances of a fire or other physical damage due to a lighting attachment to the structure. They neither repel nor attract lighting, except over the small area that they're intended to protect. The fact that they're not required for new construction has everything to do with cost and risk management and nothing to do with whether or not they work.

Lightning effects are divided into two categories, direct effects, which are the result of the passage of the actual lightning current through a structure, and indirect effects, which are the results of the transient voltages generated by the lightning strike. Most of the effects such as burned out electronics are indirect effects resulting from the transient voltage induced on power, phone, or cable conductors. That's why stuff can get damaged from a strike some distance down the line.

In conclusion, yes its worth the effort to put the rods back, since you already have all the materials and there wouldn't be much labor involved.

Keith

Bob

Lightning will start a fire when the there is enough energy deposited into the material its passing through to raise the material temperature to the ignition point. Depending on how flamable the material is, a fire may or may not sustain itself once the lighting stike is over.

Keith

Positive lightning is stronger and lasts longer then 95% of cloud-to-ground lightning which is "Negative Lightning" -- before I knew about the names and differences, I did know there was a different "look" to the type of lightning that was likely to start a fire and you could usually predict which storms would start fires from looking at the bolts. Also knew we the fires usually started by strikes at the end of the storm, sometimes at the beginning -- but seldom in the middle of it.

For a fairly small town that may see 3-4 structure fires in a year, 1/4 of those are lightning strikes which always surprises me just how common it is.

Of those fires, 3/4 of them are basement fires when the lightning hits a tree in the yard or well and follows the plumbing / wiring inside. The other 1/4 are attic fires after the roof gets hit.

Hard to cast a vote either way, not being knowledgable enough on the subject, but if the system is in-tact and all you have to do is temporarily re-locate or disconnect the fasteners that hold it, while performing the roofing work, seems like it should stay, to replace that system would certainly be a cost and it would seem that such a system should have value in that it creates a path for the electricity to discharge, whatever way it travels.

• ALRCI

The house I grew up in in Ohio always had lightning rods and was hit by lightning three time that I know of. One time a ball of energy came down the chimney into the living room and did lots of damage. There are many pros and cons. I now live in a house with metal roofing. Don't know how that factors in. By the way, metal roofing in pretty much a longtime fix and can save you money over the long haul. More people are using it.