Saturday, June 3, 2017

electricity - Is wearing metal armor during lightning safe?


I recently saw in a television show that wearing a metal armor during lightning is good because metal provides the path of least resistance for electricity to flow to the ground. Now my question is,is it really safe for the man inside?If he is in contact with the armor the electricity will try to flow through his body which will face grater resistance and burn him (as $H=I^2RT$). So, am I correct or the wrong that the person inside is not safe?



Answer



Metal is much more conducting than the human body, but in order for an armor to act as a Faraday cage the shoes and soles also should be metal soldered on the armor. Otherwise the body will be the line to the ground.


These insights in instructions for metallic cars is enlightening:




Reported incidents and related injuries make it clear that a person inside a fully enclosed metal vehicle must not be touching metallic objects referenced to the outside of the car. Door and window handles, radio dials, CB microphones, gearshifts, steering wheels, and other inside-to-outside metal objects should be left alone during close-in lightning events.



Wearing a metal armor makes it impossible not to be touching the skin someplace.



Damage. Reported damage to vehicles includes pitting, arcing, and burning on both exterior and interior places. See the photographs below, courtesy of Mr. Brown, of his Jeep Cherokee that was struck by lightning. Cases have been reported of total destruction of vehicle wiring, and associated electrical and electronic systems. Cases from police departments report bad burns to the hands and mouth where officers were using radio microphones when their vehicles were struck.



Interior to an armor means your skin. Bad burns may happen.


In addition the human shape is pointy. Covered by metal it becomes a lightning rod, from which streamers that go up and meet the down coming leaders will start, just because of the metal and the geometry and the strong electric fields in thunderstorms.


This video is wrong, imo, to give a check to the armor. Ignores the huge number of Joules, between 1 to 10 billion joules which will heat up the armor and the impossibility of no contact between body and armor. A google search gives a lot of weight to this urban myth.



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