Lightning rods

[BoFuller]

I did a search and didn't find anything. The last couple evenings I have been sitting out watching the thunderstorms and some of the lightning was extremely loud and very close. Do any of you use lightning rods on your homes? I'm sitting up pretty far on the hill, but not at the top. Any pros and cons to use of lightning rods?

[rreidnauer]

I don't think it's a terribly bad thing, though it's probably mostly benign. I've thought for sure that my heavily grounded radio tower would have taken a hit by now, but hasn't happened. Of course, with that said, years ago, a friend of mine had an ungrounded CB radio tower of about 50' attached to the house get hit, and the lightning came down the mast, but took a turn through the asbestos siding to jump into a piece of romex wire in the wall, which led to a small fire. So, if you want lightning rods, don't expect them to attract lightning, but be sure to strictly follow grounding guidelines if you do.

[project]

I have a 160' radio tower and can't believe that I haven't been hit yet.

[AkChas]

Bo - Unless you're the only thing around for miles and the highest thing at that, I wouldn't be putting up a lightning rod to INVITE a bolt over to my house. Let the surrounding trees / terrain take the hit. Extremely high temp lightning bolts and wood, don't tend to mix well. That doesn't preclude you from grounding your place via a good ground (ground rod, ground mesh/matrix, depending on local conductivity).

[loghousenut]

Not wanting to hijack the thread, but not wanting to miss a chance for an old LHN story either. Just after the Boss and I got legal, 24 years ago, we were living in the old bus, way out on the other side of noplace, in a fairly remote piece of southern Oregon heaven. We had 6 miles of our own private phone line that ran across Forest Service property. It was a single wire "farmer line" that used the Earth as a return line to the converter box at the end of the County Road 6 miles away. It was a 40 year old system and the wire was about 1/8" diameter and mostly laying on the ground. Yes, it was fun (but a lot of work) to maintain service.

I was out on a truck, making a living, and Patty was home in the bus trying to occupy herself during a summer thunderstorm. The phone was an ancient desktop rotary dial phone and it was sitting on the kitchen table about a foot from Patty. All of a sudden there was one of those "right HERE and right NOW!!!" lightening flashes with the accompanying big noise. At the same time there was a big arc of lightening between the mouthpiece on the phone and the aluminum frame of the closest window on the bus. She said it smelled funny and it was like everything glowed for an instant. She wanted to call someone but thought she should let the phone just sit there as she snuggled down in bed with the dog and let the thunderstorm pass.

When I got home and she told me the story I was surprised to hear her tell such a whopper. She's kinda well grounded and not prone to exaggeration. True, the phone was fried, as was a bunch of phone wire, but I knew better than to believe her "hand of God reaching out" story. Next day I ran into town to see the guy at the phone company who had educated me about how to keep this system alive. He asked how far it was to the closest lightening arrester. From his description, I knew there was no such thing in our 6 miles of wire. He backed up her account of what happened and blasted me for being such an idiot. He rounded up a box full of lightening arrestors and ordered me to put one at each test point (test points were 1 mile apart).

In the process of running new wire, I came across the old original lightening arrestor nailed to the side of an old outbuilding but it had been bypassed long ago. It was a spark plug. The phone line was hooked to the top of the spark plug and then the line going to the phone was connected to the other electrode but went straight off to the side at a right angle from the plug. The bent wire electrode of the spark plug was connected to a ground wire that went straight to a ground rod. The idea was that a jolt of lightening would come straight in on the phone wire and, instead of turning 90 degrees, would jump the gap in the spark plug and go straight to ground.

Sure glad the old Gal didn't get herself fried that day.

[WNYcabinplannin]

Wow! Great story!
I've always wondered about the scenes in the chic flic I think it was sweet home Alabama (w/ Reese Witherspoon )
Where the guy put rebar or lightning rods in the sand on the beach before the storms, and it'd strike and make big balls of glass in the sand. Was that just Hollywood or could that work??

[rreidnauer]

Where the guy put rebar or lightning rods in the sand on the beach before the storms, and it'd strike and make big balls of glass in the sand. Was that just Hollywood or could that work??Partly true. I recall a show where some scientists were experimenting with barrels of sand. They were launching model rockets during thunderstorms, trailing a fine metal wire connected at the top of the sand stack in the barrel. Every once in a while they'd get a strike, then would carefully dig out the sand to reveal a rough, random fused-sand tube where the bolt had passed through the sand.

I wouldn't expect any pretty glass orbs being formed though.

[AkChas]

Partly true. I recall a show where some scientists were experimenting with barrels of sand. They were launching model rockets during thunderstorms, trailing a fine metal wire connected at the top of the sand stack in the barrel. Every once in a while they'd get a strike, then would carefully dig out the sand to reveal a rough, random fused-sand tube where the bolt had passed through the sand.

I wouldn't expect any pretty glass orbs being formed though.

I saw that one too! Pretty cool.

[hammerhead 67]

Did a bunch of research on this prior to a sailing trip in the Bahamas.

There are 2 operating theories.

1. The lightning rod at the top of a sailboat mast is not to attract lightning but to disperse the charged ions which are seeking the opposite charge in the clouds. Typically the mast top "rod" is several feather like rods to increase surface area. The theory is that this will provide a small cone of protection over and around the boat. Since the ions have ridden up the mast and dispersed off the rods, there should be LESS charged particles in the cone around the boat making it less likely to be hit by lightning. IF lighting was to strike, it would ride the outside of the cone of charged particles to the opposite charge/ground thus missing the boat.
Real world results are mixed.

2. Second theory is simply providing a desired path to ground. Lighting rod at the top of the mast leading down a heavy wire to the lead filled keel at the bottom of the boat. In the event of lighting strike, the charge follows the path to ground without damaging the boat. Results are mixed in real life, from no damage at all, to minor electronics damage to blowing the keel off the bottom of a fiberglass boat.

The research did nothing to alleviate the pucker factor when we got into a couple thunder storms that more closely resembled an artillery barrage mating with a fireworks show.

We have several lighting damaged trees in the general area of where we are building. In fact, the farmer next door had a haybale hit by lighting and catch on fire 3 weeks ago. I am thinking of rigging up a couple lighting rods on those half dead trees. With any luck, lighting will hit the sacrificial tree and not the house.

[rreidnauer]

Did a bunch of research on this prior to a sailing trip in the Bahamas. . . . . . . . Results are mixed in real life, from no damage at all, to minor electronics damage to blowing the keel off the bottom of a fiberglass boat.The answer is simple. Take that sailing trip in a submarine! ;)

I do wonder if those multi sharpened stainless wire dissipators work to alleviate the charge buildup and arrest a full on strike. I can understand the concept of it. Anyone with an old tube type TV can play with that theory. Turn on the set and move your finger near the screen and you'll get an instant static snap. However do the same again, but hold a pin towards the screen and slowly move towards the screen, and you can hear the charge slowly bleed off, and you never get the snap.

But that's comparing inches to miles when talking static, and I doubt the two respond in similar manner.