Why static electricity only concentrates and flows on the surface? Anything insides Faraday Cage or Faraday Suit is protected from Electric Field outside. I don't understand what restricts the flow of free electrons to surface on the cage only? How does that happen? Could you explain me please?
 A: Suppose we have a metal loop, with a circular cross section, suspended by an insulator. If several electrons were added to the loop, you can easily see that the extra electrons would move to the outside of the loop to maximize the distance between them. We can add more electrons until the distance between the electrons become shorter than the diameter of the metal loop, then there will be some electrons on the inner side. If we stretch the loop to form a sphere, it would take a large charge before any electrons are forced to the inner side.
A: I have just do some calculation. If we consider an arbitrary closed Gaussian surface wholly within the conductor material, this cannot contain charge since everywhere on the surface $E=0$. Therefore, inside the conductor, the charge is zero at every point.
A: same charge repel each other, electron repel other electron so it mostly stay as far from each other as possible. so it go to surface of object
However faraday cage is another thing. It just the air is insulater for anything inside the cage, not because charge flow on surface
