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?
$\begingroup$
$\endgroup$
3
-
$\begingroup$ I think the biggest problem is that some parts of the armor because of their shape, will create higher concentrations of charges, hence large electric fields and atract more lightnings. And although current should flow only through the armor, it will heat up considerably. Also it provides no shock wave protection. $\endgroup$– rmhleoSep 9, 2015 at 9:53
-
1$\begingroup$ Not everything that is on tv (or the internet) is true. Yes, it is true that a Faraday cage can protect against electric fields and lightning, but armor is not a Faraday cage, at least not unless it has rather solid copper wires connecting the moving pieces. I would even suggest that the parts would have to be welded together to produce a sufficiently low impedance system, otherwise the potential differences will be plenty large enough to electrocute the person on the inside. $\endgroup$– CuriousOneSep 9, 2015 at 10:04
-
1$\begingroup$ The idea that electric current does "follows the path of least resistance" is an over-simplification. If you provide an electric charge with two paths to ground, current will flow through both paths. If one path has less resistance, then it will receive a larger share of the current, but it won't receive all of the current. $\endgroup$– Solomon SlowOct 17, 2017 at 21:18
Add a comment
|
2 Answers
$\begingroup$
$\endgroup$
2
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.
$\begingroup$
$\endgroup$
Given that the alternative is being blasted by lightning without wearing armor I would say there is a better chance of surviving simply because it would divert most of the current away from the heart.