Having electrical work done on my house today & this thought popped into my head 😊
m0le: Your body uses electrical signals in its nerves, which is why electricians are told it’s better to brush a suspect wire with the back of your hand (so the involuntary cramp pushes your hand away rather than clamps on). The major way people die from electric shocks is if it goes through the heart. Your heart is a finely tuned machine that does not appreciate a sudden external signal saying contract all muscles. If you’re lucky, your heart resumes beating with its normal pattern. If not, hope someone around knows CPR.
Incidentally, this is also a bugbear for medical shows – the device with the paddles and the shouting clear doesn’t restart the heart, it stops the heart and is used when the rhythm has gone wrong (called fibrillation). The heart can then restart itself with the correct rhythm (hopefully).
Edit: thanks to the 5000 electricians who have correctly pointed out that devices exist for checking if a circuit is live. Use a device if you have one (and if you haven’t got one, why are you working on your electrics?). The only time that tip saved by bacon was when I found an unknown wire in my loft. The main house breaker was off, but it turned out some enterprising previous owner had hooked the loft lights up to my neighbours power. 240V is unpleasant (and made my hand & arm contract fast enough to bruise all my knuckles on a joist).
bmrhoads: The human body is not a perfect conductor for electricity and when electricity encounters resistance it generates heat. If you happen to become a part of an electrical current of a high enough amperage(the measurement of an electrical current), you could be severely burned.
More importantly, electricity causes muscle contractions. Since our body controls its muscles through the nervous system with electrical signals, an overload of these signals might cause serious contractions and even paralysis. What’s worse is that this could even cause your respiratory system to fail and ultimately stop your heart.
kodack10: There are two things really. One of the biggies, is that often electrocution over rides conscious muscle control, and so the person who becomes electrocuted is unable to let go or jump back out of harms way once it starts. They may be thrown clear by their own muscles spasming, or they may instead grip the wire even tighter.
1. Your autonomous nervous system such as heart beat and your internal organs, uses electrical impulses to keep everything working. Electrocution can interrupt or over ride these signals, preventing the heart from beating correctly or sometimes stopping the heart all together. In order for this to happen, the electricity must pass over the critical chest area and vagus nerve. For example touching a livewire with both hands would form a connection from one hand, through the arm, chest, and out the other arm, stopping the heart. Grabbing it one handed might cause it to form a circuit going up the arm, down the side of the body and through the feet.
It doesn’t take much amperage for this to happen, but it usually requires high voltage. Also alternating current is more disruptive to the body than direct current, and more likely to electrocute somebody even at lower amps and voltage.
And #2 Amperage can cause burns. The same action that causes the filament in a light bulb to glow bright orange, causes your body tissue to get hot and can cause electrical burns as the rapid influx of electricity pushes past the electrical resistance of the body and creating heat in it’s wake. These types of electrocutions may not stop the heart, but may literally cook the body. People who get electrocuted and have to have limbs amputated, are usually the ones who were burned by high amperage but not long enough to kill them.
Direct Current with low resistance and high amperage can cause electrical burns to a person just as readily as alternating current can. Amps kill and amps burn. Even a lower voltage direct current could burn you readily if the amperage is high and resistance is low.
This is also responsible for the numb tongue you get when licking a 9v battery. The tongue completes the circuit and begins to be burned, which causes us to yank the battery away before any real damage is done.
Thneed1: Lots of talk here about stopping hearts, burns, etc.
Those are the kinds of effects from lower amounts of power, like household electrical outlets.
Once you get up to larger amounts of power ( for example a piece of equipment touching an overhead line, or giant cable that power buildings), your heart stopping is the least of your worries. Your heart will be cooked far beyond well done before it even has a chance to stop. It would cook you instantly from the inside out.
A downed live power line can kill you even if you are standing ten feet away, and you can be electrocuted by standing with your legs too far apart.
formervoater2: There are two things that make it dangerous.
First, if it takes the right path through your body it overpowers the proper signals from your nervous system causing heart to stop beating or beat too rapidly and weakly to effectively pump any blood. It can also mess up the signaling in your brain, rendering you brain dead.
Second, if you have a power source able to supply high current and you connect something with some, but not very much, resistance across it a lot of power will go into it and it will heat up really fast and possibly explode. Short circuits are typically what causes this.
yJIuTo4Ka: Not claiming this is full answer, but every energy transfer has it energy losses (like frictional losses with every object movements).
In this case losses come as heating. Just whole your body heats, as energy/electricity comes through you. That’s why you are literally will be burn to death in worst cases (your brain will be fried). In common cases youll just have burns and singes. And in rare cases only some of you neurons will be burn, so you could achieve only a partial paralysis.
Apparently, this heat losses is a reason why an electricity burns treats almost as common ones. Something like this, sry for englando.
zeidrich: A couple of things.
First your nerves make you do things like contract muscles. The signals get passed through the movement of ions that creates an electrical potential (voltage) that causes a reaction to do something like constrict the muscle. If you create that voltage in another way than moving those ions naturally, your muscle still contracts. This causes bad things to happen like injury from your muscles contracting, or contracting and relaxing quickly in the case of AC. You can end up sending yourself flying, or causing other damage. Your heart is also a muscle so it can disrupt your heart by screwing up its rhythm by forcing it to contract and relax 60 times a second.
The next part of it is that as current passes through something with high resistance it creates heat. This can cause burns, burns are generally bad, but electricity can burn you inside.
But that’s basically it, it interferes with signals traveling across our neurons, this on its own is temporary, but the physical response, like our muscles all contracting and throwing us backwards can be damaging, or our heart going into fibrillation, can be very dangerous or life threatening. Then, it causes burns as it travels through your body to ground, these burns can be internal, and a lot of things internally handle being burnt a lot worse than your skin can handle it.
High voltage AC is dangerous because it will make you go flying and make your heart go into fibrillation, and you can get burned. High voltage DC is dangerous because it will cause you to grip tighter on to whatever you grabbed on to to, and you will be unable to let go while you cook, and it can stop your heart.
These aren’t the only things that they do, but it’s the gist of it. You don’t want voltages higher than a few mV at most generated by external electricity or it will cause your neurons to fire inappropriately. You don’t want enough current to go through your body that your resistance adds enough energy to start reactions that shouldn’t be happening, like proteins reacting and denaturing.
“Electricity” isn’t dangerous. The problem is it’s required for our bodies to function. But because our bodies rely on electrical potentials to be a certain way, having that potential change because of something outside of our body makes that not work. Otherwise it’s not electricity that’s damaging us, it’s heat caused by that electricity. The wrong kind of electricity at the wrong place is dangerous.
But that’s like saying what is it about gasoline that makes it so dangerous to a car? It’s not dangerous to a car, it’s necessary for a car to function. But if you go to a gas tank, and fill every crevasse your car with gasoline, that’s not good. Not because the gas is specifically dangerous to cars, but because while the car needs gas, it needs to have areas without gas, it needs gasoline vapors to ignite, not liquid gas in the engine, it can’t wash the windows with gasoline instead of wiper fluid, it can’t vent exhaust when that’s filled with gasoline, and a spark from the battery or spark plug can cause the whole car to burst into flames.
Like gasoline, electricity can cause burns/heat to pretty much anything. Like the engine in a car needs to have a particular ratio of gasoline to not-gasoline to work properly, the human body needs a particular combination of high and low electrical potentials to be in a working state.
If you stick your fork in an electrical socket, that’s pretty much like going to the gas station and pouring the gas all over your car. Neither are a good idea, but it doesn’t mean gasoline is particularly dangerous to cars.