Lightning strike

[capncarl]

So.... It appears that lightning rods were an early American marketing ploy! Kinda like the big box stores selling extended warranties, playing on customers fears. I could see an old Sears Roebuck catalogue or magazine with a lot of hype about some houses getting struck by lightning and lightning rod sales soar!
Capitalism at its finest!

[cwsmith]

The thought that lightning is inevitable probably goes into a lot of the thinking over "lightning rods". It's simply going to happen, and if you own (or are) a fairly high structure, then that is a pretty prominent target for lightning. Lightning Rods would offer an easier path to ground than your barn or silo roof. The problem of course is that lightning is not totally predictable and what may seem like a logical target or pathway, may not be so. Still, a lightning rod seems like a better pathway than the metal roof's peak on your barn. It would at least provide a less destructive path. However, much of the challenge (as I understand it) is to bleed off static electricity, which is often the attraction of a strike.

When I got my Ham Radio license back in the early 90's, the thought of a lightning strike was pretty concerning. To maximize my ability to send and receive, you've got to have a decent antenna system. Considering cost and efficiency, I decided to put up approximately 300 feet of wire to make what we call a "delta loop". Worked fantastic, but imagine having 300 ft of wire hanging like a big halo over your house, in a lightning prone area. Add to that big wire circuit the fact that it is tied directly into your house and hooks to your radio via a coax cable!

For me, a lightning arrester and a good grounding system was essential; but even then, the thought of such a strike entering the house would be devastating to say the least! While I never could find a definitive answer, what I did find in my reading was that the build-up of static electricity was a major factor in many recorded strikes. To that end, I installed two grounding rods (as defined by NEC) and then bonded that cable to a 1/4-inch thick copper plate on the outside of the concrete basement wall where the coax came in. The outer copper shield was directly attached to the plate.

At my desk, I had a copper pipe running horizontal at the back wall with welded lugs attached at intervals. All my equipment: transceivers, antenna tuner, and power supply were all attached to that pipe via heavy copper braid and the pipe itself strapped back to the grounding plate at the entry point. Further, I added a coax connector to the the grounding pipe and when my equipment was not in use, I'd simply remove the coax from the back of my radio and attach it directly to the ground pipe; thus grounding both the outer shield and the center RF feed. Idea was to keep any static from building on the wire antenna and out of the radio equipment and removing the path directly to my radio's sensitive circuitry.


As rain and wind shear across the surface of a wire or other conductive materail, static electricity builds pretty rapidly. That can be almost anything that can conduct, including non-conductors that get wet and thus conduct. So whether it's wire or rigging on a boat (Moby Dick, Saint Elmo's Fire) you've got a probable for static build-up.

But of course it doesn't always have to be raining and you can simply be out there on the golf coarse where you may be the highest object that lightning is looking to discharge to. Lone trees are also a problem, but even in a stand of trees you'd be taking a chance should you decide to seek shelter there.

I'm no expert by any means, but my quest to be safe caused me to read a lot. Problem was that I could never find a definitive answer, where someone said just said do this or that and you'll NEVER get struck! So what I did seemed to work... or was I just lucky?

CWS

[onedash]

Tree guys came and cut them down. It's pretty cool watching the climber at the top of the tree. He cut off some branches and then the top before felling the first one to avoid hitting other tree branches. The second tree had two trunks. It y'ed at 4 feet from the ground and they were very perfect straight poles so they cut one off and then the rest of the tree. I got almost all of it cleaned up. Still have a few small logs to move but that can wait till the weekend. I signed up for a surge protector on the meter from my electric company. $5.25 a month. So about $1,000 every 16 years. if that along with surge protectors can stop my devices from getting fried I guess it's a good investment. It is advertised to only protect big items like electric water heater, fridge etc... I read the fine print on the surge protector I just bought and it only covers your devices with the replacement warranty for five years. And based on what my buddy told me it takes about 3 months to get a check from damaged items. They also give you a 2 outlet surge protector when you get the one installed on the meter.

[LCHIEN]

Lightning is difficult to predict. You have 100,000 Amps in typical lightning strike.

You have water, pour a little trickle on a roof and it will find a meandering path and run a simple rivulet down the roof.
Pour a 100 gallons on the roof suddenly and it will flow everywhere. Some will even flow uphill for a ways.
Lightning is like that, It will find the most unusual paths as 100,000 Amps works its way around...seeking an easy path to ground. It will split into many rivulets of 100 A here and 100 A there. Its just not very predictable.It can even jump many feet through the air (again).