eli5 Why is touching a live wire dangerous? Doesn’t electricity take the path of least resistance? Wouldn’t your hand be a much worse conductor than a copper wire?
In: Engineering
It takes the path of least resistance to the ground. Most of the time in a home, that is through a copper rod that is driven into the ground outside. If you touch the wire and are not insulated, you become the quickest way to the ground.
Yeah but the copper wire isn’t offering a path to the ground at all. If there was a copper rod going from the wire into the ground right beside where your hand was, then yes the electricity would prefer the copper, which has lower resistance than your skin.
But in your scenario, your body is offering *the only available* path to ground, and it’s much better than nothing. The only other option is jumping through the air, which is a pretty good insulator. Compared to air, your body might as well be copper.
Simply put, the voltage (electrical potential energy), is finding a more direct (easier) path to ground through you. If it continues through the wires, it’d end up also having to deal with whatever loads are on those wires, assuming there are any loads at all. So the voltage can take a path through, say, a heater or motor with lots of resistance, or you with less resistance. Doesn’t matter much that the wires leading there are low resistance.
There’s more details to it but I’ll leave that to someone more familiar with electrical circuits.
Electricity always takes all available paths. If you have a microwave, a toaster, and a lamp plugged in side by side they will all turn on.
Now, you probably aren’t a *super* appealing path for electricity. If the electricity can choose between going through you, or going through a wire, it will mostly choose the wire. If the electricity must choose between you and a refrigerator, well, you’ll end up getting a larger dose. It doesn’t actually take that much electricity to kill you, compared to the energy draw from a regular household appliance.
It specifically wants to get to the ground, and in this scenario, the options are going through air or your body, and your body IS the path of least resistance in that case since air is a great insulator of electricity
We are made of salty water, excellent conductor.
Touching a live wire goes up you arm to your heart, stopping it, then down your torso to a leg to the ground.
Gotta be right flavor of electricity, like those plasma toys from Spencer’s won’t do anything, but the real stuff will excite your heart into a locked position & will prolly not restart its rhythm.
Electricity takes all paths. The idea of “least resistance” is objectively incorrect and dangerous.
Think of it this way, take a plastic bottle and punch a few large holes and small holes. Then fill it up with water and watch it leak. Every hole, large or small has a some leakage – more in the larger hole less in the smaller hole. This is how electricity works – electricity takes ALL paths possible. More in the easier path and less on the more difficult part.
If you happen to be on one of the paths, some current will flow through you – and humans don’t need lots of current for it to be dangerous.
A ‘hot’ wire has a big potential difference and nowhere to go. If you touch it, you suddenly act like a badly designed electric heater plugged into the circuit. A modest amount of energy from the wire will flow out, though you, and to ground. In the process, the parts of your body conducting electricity will be disrupted and heated.
Why doesn’t it stay in the wire? Because you might be a badly designed heater, but you give -some- path to the ground/a lower potential state. There’s no path in the wire, it just ends up waiting there.
Exception: A dead short in the circuit before you, like a wire that goes right from the hot wire to the return or to a ground, will likely protect you from touching a hot wire. The hot wire also won’t stay hot very long though, because a dead short will rapidly heat up the wire as power rushes though it as fast as it can, so either the wire will fail or (hopefully) a breaker or fuse will open the circuit and stop the power.
Two misconceptions here: Electricity takes all paths in proportion to how well they conduct electricity, and the hot wire doesn’t normally drop in voltage much when loads are added. It does drop a little because the wires aren’t superconductors, but anything drawing enough current to drop it a lot will trip the breaker from overcurrent.
The resistance of your body also isn’t a single fixed value, the resistance of your skin especially changes drastically with how wet it is, and high voltages will break the skin down and decrease the resistance further.
Imagine your skin is like a special suit that keeps you safe from little electric shocks, like a superhero costume! This keeps you safe when you touch things like lamps or TVs.
But just like a superhero suit can get ripped, really strong electricity can break through your skin’s protection. This is called “breakdown voltage.”
When your skin is dry, it’s like a super strong suit! It takes a LOT of zap, like from a very strong battery, for the electricity to break through (around 20-40 volts). That’s like needing a giant villain to rip your super strong suit!
But when your skin is wet, from things like playing in puddles, it’s more like a regular raincoat. Even a small zap (less than 20 volts) might be enough to break through, like a tiny raindrop getting through a hole in your coat.
The important thing to remember is that even a small zap can be dangerous. So always treat electricity like a villain: avoid it completely and tell a grownup if you see anything sparking or acting weird! They can help keep you safe.
–Google Gemini
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