Lightening Strike

[nelz]

I think when talking about lightning, people assume that if you get struck, you're dead, end of story. But a large portion of those struck in fact do not die, though some wish they had.

I know a guy who got struck and survived. However, he claims it gave him super powers, like he's a super he-man stud after that. No, seriously, not kidding.   

[Ron Jones]

1.21 Gigawatts!

I've heard it's hotter than the surface of the sun too. 

ROFL!!!

[Makule]

Two days in a row, while fishing off the Kau coast of the Big Island of Hawaii, there were thunder clouds that moved from the mountains towards the ocean and they passed immediately overhead of us.  Wanting to take advantage of the winds blowing offshore, I rigged up a line with a kite and flew it as the clouds were moving above us.  Brilliant guy that I am, I totally forgot the Ben Franklin experiment even after I started feeling a little tingling.  Only realized what I did (twice) after I got home.  Fortunately, there weren't any lightning flashes that came down the line.  God was certainly looking after me on those two days.

[Gfish]

I think when talking about lightning, people assume that if you get struck, you're dead, end of story. But a large portion of those struck in fact do not die, though some wish they had.

I know a guy who got struck and survived. However, he claims it gave him super powers, like he's a super he-man stud after that. No, seriously, not kidding.   

HA! Sounds like a story someone like me would try on the ladies to maybe get them interested.

[nelz]

Now don't y'all go out lookin' to git struck hopin' to git dem  super powers  now, ya heah? 

[philaroman]

oh, just send out RC boat w/ lightning rod, then go scoop up poached fish (after storm, of course)

I think when talking about lightning, people assume that if you get struck, you're dead, end of story. But a large portion of those struck in fact do not die, though some wish they had.

I know a guy who got struck and survived. However, he claims it gave him super powers, like he's a super he-man stud after that. No, seriously, not kidding.  

HA! Sounds like a story someone like me would try on the ladies to maybe get them interested.

don't do it -- they're more likely to think there's a lodged, battery-powered device involved   

[Brewcrafter]

And while it was mentioned that even if you are struck, many survive (you lost me at "impotence"!) what is more insidious is that electricity being the predictably capricious critter she is, can strike strike at a distance and still have horiffic consequences.  For example leaning on/working on/touching a wire fence that gets hit on the other side of the farm or pasture.  Conductor city! - john

[smnaguwa]

Bill, be careful even in So CA. I was stationed at March AFB in Riverside when 4 airmen were working on a plane wing during a thunderstorm. Unfortunately, they were struck by lightning - 1 died. He had a burn on the upper body and his shoe had a large burn hole. We couldn't get his heart re-started. The others had burn injuries and nerve/muscle problems. I'll never forget that night.

[PacRat]

Airports are notorious for lightning activity. Our biggest client is FedEx (mostly their Memphis hub). We also protect UPS at their Louisville hub. We don't recommend lightning rods (even though they are the accepted standard).
-Mike

[Wompus Cat]

Hey Mike what do you Recommend for a House with a Metal Roof.
House is Brick /Wood Framing . Just installed a Metal last year about 30 sq.
Got LOTS of Trees To Hit first before it hits house BUT I did get hit a few years back apparently as I noticed a Hole Burnt through the overhang Composite Shingles  right beside the Electric Meter Pole  . Got Lucky didn't burn the ol Shack down

[PacRat]

A lightning event is a complicated competition with a lot variables. Typically lightning is expected to strike the tallest topographical feature but that is not always the case. The assumption in a residential neighborhood is that all the dwellings share a fairly equal risk and that lightning will randomly strike any home in the vicinity. There's an old saying that says "Lightning doesn't strike twice." which is pretty bogus and I can fully understand your concern. There are steps you can take to minimize your damage should lightning strike again. These are the steps I  would take for a residential dwelling:

1) Put a quality surge protector at your entry panel. This should stop anything from coming in from the utility. I would also put Class A devices (plug-in) at you most important appliances (refrigerator, TVs, computers). A little secret when purchasing Class A devices is to look at the manufacturer's warranty and replacement policy. Some brand will replace damaged appliances. This is all marketing but worth looking into. Check reviews and see if the manufacturer has made good on their claims.

2) Improve you ground system. Residential code is fairly weak. I believe it calls for 25 ohms to earth and that if one ground rod doesn't achieve that you can simply drive another rod and walk away. Grounding is a 'black-art' that falls somewhere between voodoo and witch-craft but it is very important. It's can be difficult to measure this so you can just do the best you can within budget. If your soil will allow drive 20' of ground rod (do this by coupling 8' or 10' rods) this will give you pretty good results. A big roto-hammer or small jack-hammer with a ground rod tool works good but you'll have to start it from a ladder, then add a section once it's driven. If you decide to drive multiple 8' or 10' rods; you should separate them by 2.5 times their length. 8' rods at 20' apart or 19' rods at 25' apart. This maximizes efficiency. Those are the cheapest way to assure a good ground but there are ways to get much better ground if you need it but the cost is excessive for residential.

3) At the very least bond (connect) your metal roof to the ground system. If you want to really do it right, you could run a heavy braided conductor up one corner of your house then across the peak (or peaks) then down another corner. You should have ground rods at each of these drops. It's better to use aluminum for the heavy braided ground conductor. This is to prevent corrosion of your roof metal (copper tends to rust your roof metal and flashing). I don't recommend lightning rods. They do offer some level of protection but in a powerful storm their function will reverse and trigger a strike. I always recommend running the conductor but omit the lightning rods. This will basically leave you with a Faraday cage.

If you google 'NFPA780' or 'UL96A' you will be able to see the standards for industry.
That's a very basic version of what to do. The problem with residential lightning protection is that you can very easily spend more than the value of what you're trying to protect. Our industrial clients can lose hundreds of thousands of dollars in a single event so cost isn't much of a factor. If I lived in a lightning prone area, I would do no more than what I recommended.
If you want to PM me your GoogleEarth coordinates I could make some more detailed recommendations.

-Mike

[Wompus Cat]

Well that is certainly enlightening.Sorry for the pun 

Is there a formula to go by that one  arrives at a 20' depth for Grounding or can you Drill  a few feet down and then Traverse out away from structure  20 feet or so ?
Thank you very much for your info  and offer .Will P/M my coordinates .

[PacRat]

Yes, you can go shallow. I gave the 20' based on experience. I had a utility for a client and they had a 10 ohm spec. They drove several 10' rods and tested them, then screwed on extensions and drove another 10' and re-measured. I believe it took 30' to make the spec. Your soil resistivity is the variable and it changes with depth most of the time. This is likely because the soil has more moisture down there but it can also be a mineral layer.
What are your soil conditions like there?

Here's some old school advice: Back in the old days we use to take a bundle of 1/2" x 8' copperclad ground rods. I would cut the bundle in half and get twice as many rods. I would dig a trench all the way around the structure then drive the 4' rods at a minimum of 10' all the way around. You can daisy-chain all the rods together with #6 solid ground wire. You can braze or sil-phos the connections and you won't have to worry about connectors getting all crusty from being buried.

The ground rods we use now are 2 1/2" copper pipe filled with salt. We get 3 ohms from an 8' rod. We make horizontal rods for situations where there's shallow bed-rock or no access for an auger. The horizontal rods go down about 30".
There's an interesting book you might find online for free. It's called "Getting Down to Earth" by the Biddle Institute.

-Mike

[oc1]

So Mike, do you measure resistance with a regular VOM?  If you drive one of those copper rods down to shallow ground water at five feet will that pretty much guarantee low resistance?

[foakes]

This is all very good and interesting information, Mike —

Thanks for your expertise and sharing your experience regarding lightning safety.

Best, Fred