There has been so much flooding recently, and Im just wondering about how if a house floods, or any other building floods, how are people even able to stand in that water and not be electrocuted?
Aren’t plugs and outlets and such covered in water and therefore making that a really big possibility?
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Electricity takes the path of least resistance. Human bodies have more resistance than water. So if somebody jumps in to an energized pool, they likely won’t be affected. If they step in to the pool, they may complete a circuit and become the path of least resistance.
In theory, so long as you’re not completing a circuit, you can hold bare-energized wire and not get a shock.
I had a weird experience one day at the lake. There was a big crowd and people had their boats on the lake. Suddenly I began to feel the weirdest thing. I kept getting cramps on the feet and toes and sometimes other parts of my body. It turns out there was a boat I was near that had a short and a cable was in the water from the battery. I’ve been shocked by a car/boat battery before and this was way milder. So yeah, the more water the more things are are in direct contact with electricity, the less intense it is.
As others said it’s because the current is spread out in the water. Similar to how lighting can hit the ocean and you’re fine.
Electricity has a place that it starts from, and a place that it wants to get back to (the hot prong and the neutral prong of an outlet, for example).
Whenever it sees a conductive path that goes where it wants to go, it moves along that. The more conductive the path, the more electricity moves. If there are multiple paths, the electricity divides itself up proportionate to how easy/conductive the various paths are. You’re only in trouble if your body is a significant part of an easy path (or, by degrees, if there is a lot of electricity). In a massive lake, you’re relatively unimportant. There are plenty of better paths for the electricity to take.
EDIT: good chance the breaker has already tripped by the time a massive lake is involved anyway.
EDIT EDIT: this is the same principle that explains why a bird can sit on a bare high-voltage wire and not get electrocuted.
Last night we had 4 inches of water in our basement in Brooklyn. I unplugged a power strip that was completely submerged and still functioning. The reset light was still on.
The simple answer is – ordinary water isn’t very conductive. Consider that all your wiring and plugs and are already submerged in air and you are yourself in contact with that air, but you don’t get electrocuted. Pure water is more conductive than air, but still not enough to significantly affect you from any reasonable distance.
Now, if you were to have things dissolved in the water that increase its conductivity (like salt if the flooding is from seawater), conductivity will be greatly enhanced. However the electricity will take the shortest available path, which in most cases is right across the water standing between the two prongs of the plug sockets. That’s why you’ll see an arc across the plug’s contacts. The electricity has no reason to jump all the way to wherever you’re standing, some distance away from the exposed plugs.
If you were to drop a hairdryer in a bathtub though, it’s a little different. Your hand and body are right near the electrified heating element. Most of the electricity will take the normal path through the hairdryer. But some will take a secondary path through you. If you’re unlucky it will be enough to interrupt the electrical signals to your heart and cause it to stop.
Also, especially in saltwater or otherwise contaminated water, a downed mains wire or damaged underground cable can cause electrocution if you swim or wade very close to it. Firstly, power/distribution lines can carry higher voltages than what’s in your house, increasing their effective range, and secondly you will be standing very close to one end of the wire with no electrical ground (return) nearby, so you become the ground/return path. Conversely, in a home mains socket, the live and ground (return) are right next to each other (hence the two pins).
Electricity really wants to go to the ground. In house wiring, one wire will be “hot” and the other will be connected to the ground. Electricity goes through whatever you plugged in, because that’s the easiest path to the ground.
When the whole thing is covered in dirty water, the easiest path to ground is usually right across the water to the other wire, so a bunch of current flows that way. That usually overloads the system and trips the breakers, shutting off the power. You can still be shocked, though, if you’re near a wire in the water, because you might be an easier path to ground, and the electricity will flow through you instead.
Technically, the electricity takes *all* of the available paths to ground, but that’s a little over ELI5, and *most* of it takes the easiest path anyway. Also, pure water isn’t a very good conductor, but flood water is pretty much the opposite of pure.
So… because of how household electrical systems are designed… electricity wants to go to ‘the ground’. As in the floor. The dirt.
If you stick a fork in a socket, you happen to be standing /on/ the ground. The electricity passes THROUGH you. And that HURTS.
If you stick an extension cord (not touching it yourself though) in a big puddle of water, and then step in that big puddle on the other side… nothing happens to you. The electricity can pass from the cord to the ground (or back to the cord more likely, but that’s not the point). It doesn’t go through you.
Being near electricity isn’t an issue. Being in it’s path, is.
EDIT: Please do not test this. PLEASE do not stick an extension cord in a puddle. It is NOT safe because of other variables that I cannot foresee. For one, you’d have to touch the cord to get it into the puddle, thus potentially being wet+touching the cord, which violates my example case anyways.
E. Eng. here (practicing engineer, also studying for my Graduate degree). Misleading answers all over the place, here are some clarifications:
– water on your skin greatly increases your shock hazard (reduces your contact resistance) *when you are directly in contact with an electrical source*. If sitting in a large body of water, but nowhere near the electrical source, no immediate danger
– a large body of water has a proportionally large resistance. Current will flow through it and dissipate as heat. As others have mentioned, this is similar to a grounding system, where fault currents are intentionally diverted to the ground (actual earth ground, at one point) to safely dissipate the energy
– non fault currents to not have significant enough energy to propogate through large bodies of water and shock a human standing in it
– large bodies of water may not even trip a circuit. As mentioned above, large bodies of water will have a reasonably high resistance, thereby limiting the current
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