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Old 06-03-2015, 07:59 PM   #3
NN5I
Carl, nn5i
 
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Join Date: Sep 2011
Location: Tallahassee, FL
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A metal car body is indeed a pretty good Faraday shield -- most of the time -- but not necessarily during a lightning strike.

First, let's wonder what resistance might exist between the floor pan and the roof. I'd think it would not be less than about 0.01 ohm. Could be much more if body panels are poorly bonded.

What's the current in a lightning bolt? References that I've seen say typically about 30,000 amperes, but often as much as 120,000 amperes.

Now suppose that lightning current is flowing upward from ground through your car, because the lightning bolt chose your car as a target. Say, 120,000 amperes through your car body's 0.01 amperes. During the strike, there will be 1200 volts between the floor pan and the roof. Your feet are on the floor, and your head is near the roof.

Will that Faraday shield protect you? Eh? Oh, OK. I don't think so either.
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