I keep seeing videos of people coming home to a burst pipe or the neighbors above them having a flood. The water pours down from the ceiling and from the light fixtures (lights are on), but the people walking around the house don’t get electrocuted.
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Cartoons lied to you. Water is a poor conductor of electricity. However, the more salt you add the more conductive it becomes. Also, enough raw electricity can overcome the poor conductivity and the electricity will get to you.
Enjoy this guy showcasing the precise danger of water and electricity: https://www.youtube.com/watch?v=dcrY59nGxBg
Quite a few reasons.
1. A flooded house needs to be pretty extreme before it gets to the height of power outlets. Usually water flows either down stairs or out doors before it builds up in a house (unless we’re talking about water from outside coming in). The wide majority of wiring in a house is insulated, so some water running near those wires isn’t a problem. This is why you can have your electrical wires in the wall right next to your metal water pipes without causing a problem.
2. Electrical systems will typically shut off when they’re drawing an unsafe amount of electricity — this is what the circuit breakers in your house do. By the time you could walk into an electrified pool, the circuit has probably been shut down.
3. Home electric systems don’t have that much power relative to a giant pool of water. If a whole home is flooded, any electricity in the pool is being spread out, making it less dangerous.
4. Electricity is really only dangerous when it is going somewhere. Electricity is lazy and will usually take the easiest path. Jumping in a non-continuous stream of water from the lamp to the floor isn’t *generally* going to be easier than just going through the lamp.
As for actual flooded homes — where people are probably walking around with rubber boots in several thousand gallons of water — the human body is probably not the most conductive path to ground. So even if there is electricity, it probably won’t try to run through a person.
That said, live power lines are *always dangerous*, so don’t just go walking around in random flooded houses assuming its safe.
The rate at which voltage drops off in water is incredibly fast. Your home has 240 volts maximum. Even in conductive water it at most could travel maybe a foot. Even a lightning strike is dissipated within about 5 feet of where it strikes (otherwise you would have lakes full of dead fish every thunderstorm).
To get shocked, you need a difference in potential, for electricity to flow anywhere. That’s why birds can sit on a high voltage line, because the wire is all at the same potential. They would need to reach their little foot over and touch the pole or a ground wire to get zapped.
A flood of water would probably be at the same potential as ground, since it’s in contact with pipes that go into the ground. If you were to touch a live wire, or any electrical connection that’s hot while standing in water, you could get zapped, same as if you’re standing on the ground and touch a live wire. But if the water itself contacts a live wire, the electricity will only flow to the easiest path to ground, and would probably blow a fuse if the resistance is low enough. But no matter what happens, the water is all at the same potential, so there’s no place for the electricity to flow.
Main thing is, electrical code dictates a ground. If your house was built to code, the most efficient route for electricity is the ground wire which should be bonded to all metal pipes in your house.
The ground also happens to exist in every outlet and switch and should always be the closest possible discharge route from any live wire.
So.. even if the water does reach a source of electricity there should be a ground really close by which will always be the most efficient path. Given the high resistance of water, it might not trip the breaker but it will also not decide to take a much longer path and electrocute you. If your house was built even more recently, code requires arc fault and gfi breakers for a lot of the rooms which would 100% trigger and shut off in the above scenario.
Water has a very high resistance as does your body. If electricity will travel to a ground using you or water, it will always take the shortest possible path and your body will not be on it given what i said above.
**Short answer, flood gives electricity the chance to pick its most preferred return path. There are times that it doesn’t prefer you. So you won’t get electrocuted.**
Long answer, Electricity returns to the source which is the power plant. Under normal conditions, its return path is via neutral wire (which is connected to the ground wire at your main that is connected to the grounding rod buried in soil/earth). The power plant also has its own connection to the Earth
In the event that a flood happens and your home’s power line gets submerged, electricity will start to bypass the normal return path. And its preferred return path….is not you.
Electrical services in the wall and ground are covered in water proof pvc conduits. There are also earthing wires connected to the distribution boards that goes into an earthing pit. You can still get electrocuted if the breaker in the db was shutting off properly but modern technology advanced enough that modern breakers failing is extremely rare.
The question is how the power is still on? Any modern house with a correct electrical installation should have its mail circuit breaker shutting down the whole thing.
I had a pipe burst a few years back pouring water by litres in a nearby wall plug, the electrical panel did its job
They are! Or at least they can be. This is one of the greatest dangers when you walk into a flooded basement. I mean, it can be that the circuit breakers already switched the current off, but I wouldn’t bet my life on it.
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