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Old 06-06-2007, 09:32 AM   #16
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Almost got zapped


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Originally Posted by JohnJ0906 View Post
Yes.

Dangerous voltage levels- 30 volts dry, 15 volts wet.
Volts doesn't kill, amps kill.
If memory serves, 30 milliamps is the "let go" threshold. More current than that, and you can't let go.

Ohms law - Amps = Volts/resistance. Higher the volts, higher the Current, so higher voltages are more dangerous.

Its actually only around 15mA for the average size guy. 10 for the average female.

The electrical teacher at my high school had muscle contraction happen to him once, luckily he wasn't holding anything rather touching, but he had his muslces cramp. He told the story to every student on day 1 of classes.

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Old 06-06-2007, 10:14 AM   #17
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Almost got zapped


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....that's why if an electrical wire falls on your car in a storm DO NOT GET OUT - your tires are perfect insulators and if you were to have one foot in the car and one on the ground you would be a perfect coductor and Die.....your car is always insulated.....
Any questions let me know....
Rick
Not true. Your tires are actually pretty good conductors due to all the additives and steel belts. What protects you in a car is known as the shell effect... all the electric charge stays on the outside of the vehicle. As long as you don't touch any part of the outside of the car, you will not be shocked. If you have to escape a car in contact with a live wire, you need to jump away so that you never have part of your body in contact with the car and the ground at the same time.
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Old 06-06-2007, 01:37 PM   #18
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Almost got zapped


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Not true. Your tires are actually pretty good conductors due to all the additives and steel belts. What protects you in a car is known as the shell effect... all the electric charge stays on the outside of the vehicle. As long as you don't touch any part of the outside of the car, you will not be shocked. If you have to escape a car in contact with a live wire, you need to jump away so that you never have part of your body in contact with the car and the ground at the same time.

Yup. That is an urban legend. I remember doing the math once in physics class. We looked at an average bolt of lightning and the known resistance of rubber to figure out how thick your tire would have to be to actually prevent the grounding of lightning. It worked out to be something like 1.5 Miles thick. You would need a tire 1.5 miles thick to stop a bolt of lightning. Something like that.
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Old 06-06-2007, 01:43 PM   #19
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Almost got zapped


So what is the answer,

if I am inside the the car, lightening hit the car... will I die?

if not, I suppose I should stay in the car until someone come by (fireman) who come by to discharge all my outside charges...

but then would the gas tank expose before the fireman arrive?

should I buy those thing from auto shop to hang on the license plate which touch the ground...

Honest, when it is lightening hard.... it is very scary to drive but sometimes you have to drive...
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Old 06-06-2007, 02:05 PM   #20
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Almost got zapped


but from everything I've seen and heard (15 years fd service) you are safe inthe car, other than driving accidents, fallen trees, etc.

If a live wire was on your car you'd be told to stay in it unless there was imminent danger (fire, etc)....if wires were burning on an unoccupied car, we have to watch it burn until the utility co kills the power. (just like any electrical fire, remove the electrical charge, then extinguish like a class "A" fire (wood, etc))
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Old 06-06-2007, 02:52 PM   #21
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Almost got zapped


Shell effect? I always thought you were not supposed to touch any metal part of a car with a live wire on it, inside or outside.
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Old 06-06-2007, 02:59 PM   #22
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Almost got zapped


should we separate the case for live wire vs lightening?

as live wire has continuous supply of electricity, shell effect may not be good enough...

vs lighenning is a big accumulation of electricity which shell effect should have a role...
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Old 06-06-2007, 03:02 PM   #23
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Almost got zapped


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So what is the answer,

if I am inside the the car, lightening hit the car... will I die?

if not, I suppose I should stay in the car until someone come by (fireman) who come by to discharge all my outside charges...

but then would the gas tank expose before the fireman arrive?

should I buy those thing from auto shop to hang on the license plate which touch the ground...

Honest, when it is lightening hard.... it is very scary to drive but sometimes you have to drive...
The answer is: most likely not. But there are variables. The outer shell of the car WILL usually provide the easiest path for lightning to the ground. However, lightning is a little unpredictable though and it may choose to route through you to get to the ground depending on a large number of variables. In that case, you'll likely die. Also, vapors trapped inside the fuel tank may explode as well. There are many forces at work here, but mostly you would be ok. There was a story on the news somewhere years ago - a car got struck and provided path to ground. The occupants were FINE but there was a huge hole in the ground under the car afterwards...

BTW - if you drive a saturn or a corvette, you should probably take your chances outside the car... the plastic and fiberglass respectively will not do the trick....
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Old 06-06-2007, 07:07 PM   #24
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Almost got zapped


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Originally Posted by KUI****G View Post
should we separate the case for live wire vs lightening?

as live wire has continuous supply of electricity, shell effect may not be good enough...

vs lighenning is a big accumulation of electricity which shell effect should have a role...
every material/object has a dielectric strength; the amount of voltage required for current to begin to flow. anything, with enough voltage will conduct electricity.

things like rubber (in your tires) needs something like 100,000 volts for each centimeter of thickness. You're never going to be exposed to man-made power like that on earth in your car, so if a power line lands on your car, you'll be ok if you don't step out and touch the ground while touching the chasis, just jump...

lightening kills people who aren't even near the strike, i guess that's just a luck of the draw. I never thought about discharging your car after a strike, I guess you'd have to?

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