Lightening

[patrickg]

I am curious how prevalent lightening damage and other interesting phenomena are as observed by rural folks. In just a few months at my new location I have experienced at least 2 if not 3 close encounters of the lightening variety.

My well pump is 240 volt and is on a breaker on the shops breaker pannel A N D has a fuse in each leg in the disconnect box on the wall in the well house. These are cartridge fuses about the diameter of and half as long as a .410 shell. Breaker did not trip off-line. One of the fuses looked good but was bad the other had exploded like a firecracker. They are 30 amp and are supposed to protect the pump against lightening. Replaced fuses and pump works. Second time in 4 months. A couple months ago lightening blew a limb off of a tree about 40 ft from well house. Next tree over (30 ft from well house) now has dead limbs and evidence of a lightening hit. Hopefully this is N O T predictive of how it will be in the out years.

The new alarm system installed in my mom's house 6-700 ft from well house was damaged also. It went bonkers and put digital noise on the phone line making loging onto the net virtually impossible although you could talk over the interference (a repeating seriec of clicks some louder clicks then repeat, alwas same number of soft and loud clicks.)

No other damage noted.

I saw a TV special on lightening while in Iowa and they quoted some statistics about the number of people killed each year in the US by lightening. Pretty scary stuff. Being on the phone or a computer with lightening within several miles is a very dangerous thing. One man was truly hit out of the blue. There was not a single cloud in sight (but there was one 10 miles away on the other side of a mountain) and this guy is smoked out of his socks. Another was a concert at a large outdoor sports complex. A lady in mid level seating surrounded by thousands of other people was nearly killed by lightening that did not touch anyone else. And on and on and on...

Anyone have any personal experience of lightening damage to share?

Patrick

 

[HR_Mutt]

Re: Lightning

patrickg
sure do/w3tcompact/icons/wink.gif. saw what appeared to be a large wooden water tower take a lightning strike. big errr...BIG bolt hit it right down the middle and it was instantly burning the most intense fire i've ever seen.
you have a ground wire on the pump?if you did is it still intact?
not sure why i ask i dropped outta the electric lesson thread after the first page/w3tcompact/icons/laugh.gif.
maybe it's the whacko neighbor with some super new weapon/w3tcompact/icons/wink.gif
peace thru superior firepower
regards
Mutt

 

[Bird]

Patrick, while it wasn't personal experience, the news media reported on a teenager killed (standing in his front yard) and a golfer in critical condition at the hospital in the Ft. Worth area just last week.

The only personal experience I've had was about 3 years ago when we were in the house, saw a bright flash, heard loud thunder, and found that it had burned out one TV, two telephones (one in the house; one in the shop), one lamp, the Direct TV receiver box, and one clock. We learned later that it also burned up one ceiling fan in the house next door. And we never did see where it actually hit or any damage outside.

Bird

 

[jinman]

Patrick, I recall many instances of seeing old rural homes with lightning rods installed. I think as we get more and more high-tech with low power electronics, we are going to see more damage. I can even remember the first IBM computers with static mats by the keyboard with "touch me first" printed on them because the PCs were so sensitive to static. For whatever reason, I believe if you are in a rural setting and not surrounded by metal, you should take precaution by installing lightning rods and protecting yourself as much as possible. Let's face it, if you live in tornado alley (and you and I do) you should expect some damage and protect yourself with insurance if possible also. Of course, if the bolt is big enough, nothing is going to stop the damage. Ain't triboelectricity fun?

JimI

 

[patrickg]

Re: Lightning

Mutt, When I was in the USAF (Strategic Air Command) at a base with 150 ICBM's in the ground (Multiple Reentry Vehicle types, up to 9 warheads each if memory serves) and a squadron of B-52's with several nukes in the belly and nuke warhead missles under the wings (enough firepower to basically end civilization as we know it with no help from any of the several similarly equipped bases) I used to marvel at the hudspah required to keep a straight face while contemplating the SAC motto, "Peace is Our Profession."

Ground wire, your supposed to have a ground wire? (Just kidding.) I had one, I haven't checked to see it it is intact. That poses an interesting technical challenge. If the wire is blown apart a hundred feet down in the well how would you detect that without "pulling the well"? Disconnecting electrical power and testing continuity between the ground wire and the actual "earth" (Drive in a temp ground rod for a test terminal) sounds like an indeterminate thingy. If you did not measure continuity, then the ground wire is definitely bad but if you do get continuity it could be from the burned out wire end via the well water to the earth rather than the pump body (where the ground wire is connected). I suppose a TDR (Time Domain Reflectometer) could be used. That could probably determine the distance to the end of the wire whether that was the motor case or where the wire was blown in two.

Tech note: A TDR instrument can put a signal into a wire and measure the time for the echo to be reflected back to the instrument. Time of flight divided by two and consideration for the velocity factor (percent of the speed of light of an electrical signal in that wire) will give you the distance to the discontinuity. Howszat?? If you tie a long rope to a tree, stretch it snug, and pluck it at the end away from the tree a mechanical "wave" will travel down to the tree (an abrupt change in characteristics, trees not being like a rope) and reflect back to you. Electrical waves in a conductor do that too when they hit a discontinuity like a short, open, different wire characteristic, etc.

Patrick

 

[ERNIEB]

Re: Lightning

I don't know about the technical stuff, but my closest encounter with lightning came when I was a teenager about 1968.
A few of us country boys had a couple of places where we could buy a six pack or two. We would usually drive to someones pasture and sit around on our cars drinking beer. One stormy night it was too wet for any of our usual parking spots, so me and a couple of other guys drove around on the gravel back roads. When the rain slacked up, we decided to pull over and answer natures call. We had just finished and were about to get back in the car when suddenly lightning hit an electric pole maybe 15 yards from us. The flash produced the whitest, brightest light I have ever seen. The crack was so loud it made our ears ring. I looked over my shoulder, as I was diving into the car, and I could see that a transformer had been hit and was exploding sparks into the sky. The guy driving took off like a shot, and out the rear window I could see the glowing sparks falling behind us.

Ernie

 

[patrickg]

JimI, Ben Franklin really started something with that lightening rod thing. Being just back from Iowa where I was in the company of up to 3 history buff women (could have done without the history and settled for buff) at a time. We went to look at old houses and barns and churches and cemetaries where there ancestors were burried (Including civil war vets). Anyway, there were a lot of lightening rods in evidence. I was surprised that my brother-in-law-in-law (wife's sister's husband) who is a real sharp analog EE didn't have a clue about lightening rods, grounding systems, and hoiw they worked.

Tech note: Lightening rods are not intended to be hit by lightning but are there primarily to prevent lighting from hitting a structure by draining off the static charge (potential difference/voltage) between the ground/building and the cloud/air. They are pointed on the end (small radius of curvature) because that geometry increases the electric field strength (typically well above the ionization potential of the air, about 10, 000 volts per inch in dry air at sea level with no microbiota flying through the aparatus. When the electric field is great enough (above ionization voltage) electrons are ripped out of the air's atoms rendering them positive ions. The positive ions migrate toward the negative charge (ground or cloud depending on which charge it has) and the electrons (negative) migrate toward the positive charge (ground or cloud, depending). This flow of ions (and electrons in the opposite direction) constitutes an electric current which may suffice to reduce the electric tension between the cloud and the ground enough so that a lightening bolt doesn't happen. Ground cables on lightening rods are sized to witstand a strike, not just drain a cloud because sometimes there is just too much charge and too few rods. They are laid out carefully with few bends as possible (no sharp bends) and run as short and direct to a good ground rod as possible. (This will only be on the quiz if you subscribed to TractorByNet for credit)

A large tuna clipper (not a slicer dicer for large fish but an ocean going purse seiner) came into port in San Diego, CA. Every member of the crew had been wearing an electronic digital watch. The mast was hit by lightening. The current was safely conducted through the (Gausian pill box) metal deck and hull to/from the sea from/to the cloud and didn't hit any combustibles below deck. The EMP (Electro Magnetic Pulse) from the heavy current discharge with fast rise time blew out their RADAR, Radios, Intercom, SatNAv, walkie-talkies, and everything else on board including every wrist watch. I think it hit during an all hands evolution and everone was on deck. I was just there to survey damage and recommend repairs to direction finder antenna located at the highest point of the ship on a pipe sticking above the crow's nest on top of the mast. It was T O A S T. It tried to be a lightening rod B U T failed.

Patrick

 

[TWINKLE_TOES]

Re: Lightning

Ernie,

Whoooaa... 15 yards, thats close./w3tcompact/icons/frown.gif I'm glad nature didn't call a bit earlier and I'm glad you didn't have your dog with you. /w3tcompact/icons/smile.gif

Al

 

[patrickg]

Re: Lightning

Ernie, It coulda been worse. The nature call could have been near an electric fence.

Patrick

 

[Bill_in_MI]

Took a direct hit on the power line from the transformer to the house a few years ago. It blew out the neutral line only. Everything in the house was then at 220v. Light bulbs exploding, motors (fuel oil water heater, sump pump) racing at 2 times speed. I was running around like crazy turning stuff off. Lost my computer and satellite receiver.

Another time had a hit on the satellite dish (big dish in the front field) and lost the receiver again. I suppose I could get a surge protector, but I doubt they help on direct hits...besides, for the deductable I get a technology upgrade every few years.

My now son-in-law took a hit when he was a late teen. Was riding a bike in a storm. By coincidence, another friend of ours saw it happen and immediately got help via the emergency/paramedic unit. Just knocked him senseless for awhile, but it did change his whole outlook on life for the positive.

Last incident for me was being struck while flying in a small commuter plane. We were in sunny blue sky well above the clouds when a bolt came from below and hit us in the tail section. I was in the last seat. There is not a whole lot to be scarred about 'cuz it happens so fast...flash/pop all at once...then you realize you're still intact. Captain said everything was o.k., but I could hear him testing the landing gear for the next 20 minutes. They gave out free drinks...and I took all they gave.