How does electricity figure out if you’re standing on an insulator or not?

Question

So as we know for a person to get electrocuted a circuit needs to be completed. You cannot stand on a wooden chair and get electrocuted. So when you stand on a wooden chair and touch a live wire, how does the electricity figure out that you’re standing on an insulator? Does the electricity pass through you first before failing to complete the circuit because of the wood?

In: 19

Answer 1

You can absolutely stand on a wooden chair and get electrocuted.

Electricity moves from a place where electrons are bunched up to an area where they can spread out — like gas helium in a canister moving into a balloon.

You can put barriers in the way, like a valve, but if you cram enough potential into one place, it will explode out (helium blowing up the gas canister because of too much pressure, or voltage arcing or piercing an insulating material to move to somewhere else).

Electrocution refers to being killed by electrical current. It doesn’t take much to stop a person’s heart, and the current doesn’t need to go to ground — it only needs to pass through the heart, which it can if a person completes a circuit with their two hands (in one arm and out the other). Mind you, it’s possible to head or hand to floor too, if the conditions are right.

There are materials that have a nice atomic structure that lets electrons flow easily through it like water through a pipe. There are also things that have a structure that doesn’t let electricity pass through easily, like water through concrete. When something restricts the flow, that’s called resistance. If the resistance is high, the flow is stopped (at least until the force is enough to overcome it). Ever see a spark travel from one thing to another (your finger to a doorknob after scuffing your feet on the carpet, perhaps)? That’s electricity overcoming the resistance of air to leap across the gap — about 75,000 volts are required to jump a 1” air gap.

Electricity doesn’t know where to go anymore than water does. It simply flows “downhill”, which really means “from a spot where electrons are bunched together trying to push each other away, to a place where they are spread out as much as possible or are fully absorbed by something”. It doesn’t figure out that you are standing on an insulator, it simply bumps up against too much resistance to move.