Is it possible that if i wear a faraday's cage

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Discussion Overview

The discussion revolves around the safety implications of wearing a Faraday cage during a lightning strike, exploring theoretical and practical aspects of electromagnetic shielding, thermal insulation, and the behavior of electric fields in such scenarios.

Discussion Character

  • Exploratory
  • Debate/contested
  • Technical explanation

Main Points Raised

  • Some participants propose that wearing a Faraday cage could redirect lightning around the wearer, potentially preventing harm.
  • Others caution that wearing the cage may still result in heating effects, suggesting that it might be safer to have the cage surrounding rather than worn directly.
  • Concerns are raised about the extreme temperatures associated with lightning, with one participant questioning the feasibility of thermal insulation that could withstand such heat.
  • Some participants discuss the limitations of a Faraday cage, noting that if it is not perfectly spherical, electric fields may still be present inside, potentially allowing current to flow through the air and harm the wearer.
  • There is a debate about the actual current levels in lightning strikes, with some participants suggesting that the current can be much higher than initially stated, raising concerns about safety.
  • One participant mentions that while a Faraday cage may provide some protection, it is not foolproof, and there are cases of injury in vehicles that are considered Faraday cages.
  • Another participant emphasizes the need for a sufficiently large cage to minimize the risk of lightning jumping to the wearer.

Areas of Agreement / Disagreement

Participants express a range of views on the effectiveness of a Faraday cage in protecting against lightning, with no consensus reached on its safety when worn versus being used as a surrounding structure. Disagreement exists regarding the implications of electric fields and the potential for injury even within a Faraday cage.

Contextual Notes

Participants highlight various assumptions about the behavior of electric fields, the nature of lightning, and the effectiveness of thermal insulation, indicating that these factors are not fully resolved in the discussion.

quietrain
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is it possible that if i wear a faraday's cage, does it mean that all lightning would pass through the cage into the ground (or ground electrons going up), then i would be unharmed?

thanks
 
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Yes and no.

Yes, because the electric would flow around you instead of through you.

No, because it may get a tad hot.

You'd be better off having the cage around you and not actually wearing it.
 


oh, but i could add an thermal insulator around myself in the inner side? but i read that lightning charges up the surrounding air to around 20000 celsius :O is that even possible? then wouldn't everyone around the lightning rod be cooked if we were on the roof or something

also is there such a thermal insulator that blocks off 20000 degreeC ?
 


quietrain said:
oh, but i could add an thermal insulator around myself in the inner side? but i read that lightning charges up the surrounding air to around 20000 celsius :O is that even possible? then wouldn't everyone around the lightning rod be cooked if we were on the roof or something

Yes, it is very possible.

The heating doesn't last long enough to do any damage. It's only as long as the bolt of lightning - just long enough to super heat the air to give you thunder.
 


oh so around what temperature will i feel it if i add a thermal insulator between the suit and me? i would feel nothing?
 


quietrain said:
oh so around what temperature will i feel it if i add a thermal insulator between the suit and me? i would feel nothing?

If you are touching the metal you will feel it.

If you are not, you won't feel it - look at some videos of faraday cages to see how close you can actually get.
 


thanks a lot!
 


I have read reports that people riding in cars have been severely injured when the cars were struck by lightning. A car would seem to be a fairly good Faraday cage. And it is connected to ground by the carbon black in the tires.

Also, in theory, if the Faraday cage were perfectly spherical, then the electric field inside it would be zero, because all the field vectors from the charges on the surface would cancel each other.

However, if it were not spherical, then the cancellation would not occur, and it would seem that a giant field could be present.

That field could break down the air, and allow a current to flow through the air, and through you if you were near it.

In addition, it seems significant that the lightning may not be like a current in a wire, in the sense that, in the wire, in any imaginary boundary box, the net charge is zero, because the number of protons balances the number of electrons.

However, lightning represents a net movement of charge from the ground to the sky (or the reverse), I believe. Thus, it would seem that the Faraday cage will acquire a net charge, and a gigantic charge at that. I am not sure that a simple analysis is sufficient.

Just a comment.
 


I think a perfect Faraday's cage is an electrostatic concept, because as long as currents flow in the walls of the cage, the field in the metal of the cage isn't perfectly zero (though it'll be small for a good conductor and moderate currents) and because of that the field inside the cage need not be perfectly zero either.

It should still protect by reducing the fields in the interior greatly, so if people have been hurt by lightning while riding a car, I'm guessing it could have been even worse had they not been in the car when lightning struck.
 
  • #10


so judging by a typical lightning where around 0.5C in 5ms, giving 100A (is this huge?) , i assume that since i am in a faraday cage, all the current would flow into earth?

and the generated e field due to the flowing current would not be big enough to cause a breakdown in air between the cage and me, so no spark were to fly?

or let's say i just put a thermal and electrical insulator between me and the cage, then i would be safe?
 
  • #11


Only 100A? You may want to check that. Try nearer 30,000A!

If I remember correctly, it only takes ~0.07A to kill (might be 0.7A, but it's well under an amp).

100A is big, 30,000A is horrifically high.
 
  • #12


:( so faraday cage won't do me any good?

so if i were to attach a lightning rod ,earthed, to myself, will i be spared the fury of the lightning? assuming i insulate myself from the lightning rod
 
  • #13


I'm not sure where you're pulling half of this from, but it doesn't correspond to the facts too well.

A farady cage is your best bet.

Again look at the videos available of faraday cages in action.

For lightning you'd want it to be quite big to reduce the chance of the lightning jumping to you whilst you stood in it.

For the record, you do not want to try this in real life. There is a very good chance you will be killed if it goes wrong.
 
  • #14


yea ok just wondering :) thanks
 

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