A couple of questions regarding water and electricity. Specifically, the danger of electrocution while in water. I’m aware that water itself is not a particularly good conductor, but I think the general idea is that water and electricity is still not a particularly good combination.
A week and a half ago or so, my basement flooded. The water was deep enough to cover many of the basement outlets (half of which are probably too low for code, apparently built before the code was written). I spent quite a bit of time mucking around in that water trying to salvage things before my wife and mother finally enjoined me from spending any more time down there lest something bad happen. At one point I did receive a mild shock from a surge protector, but obviously I didn’t die. The circuits never tripped, and a lamp that was plugged in remained on the whole time.
So, was I ever in any real danger? Was there so much water that any current was diffused enough to not matter? Am I just a ridiculously lucky bastard who should have been fried but didn’t for some inexplicable reason?
It’s generally considered a good idea to avoid showering during a thunderstorm, since there’s a pretty direct connection from plumbing-water-you-drain. But what about a bath? After the water has stopped, is there still danger, since there’s no longer water coming out of the faucet?
Well, pure water is not a very good conductor. But the water in your basement wasn’t pure water. Probably had lots of salts, minerals, ions and whatnot in it.
Pretty much what happens is that electricity flows through the (ions in the) water from one terminal in the outlet to the other. The hazard is when you touch something that’s plugged in. Normally you don’t provide a very good path to ground compared to what’s installed in the equipment. With all the water around, that’s not the case anymore… thus you get shocked if you handle, e.g., a surge protector. or touch a conductor that provides a good path to ground (e.g., metal plumbing in the overhead).
You’re a ridiculously lucky bastard that didn’t touch anything that made you a lethally desirable path for electrical flow.
There’s this Hollywood idea that water mysteriously all becomes “electrified” somehow and if you touch it you die. You are correct in assuming that this isn’t quite true. However, Crafter_Man is exactly right. Water and electricity don’t mix, and it’s usually easy enough to just kill the main house breaker.
Electricity kills you in two ways. The first way is that it simply cooks you to death. That’s how the electric chair works. If you take two nails and stick them into either end of a hot dog, then cut off the electric cord from your lamp and connect one wire to each nail, when you plug it in you’ll cook the hot dog in under a minute, easy. Electricity does the same thing to your body. It takes a fair amount of current, but if you’ve got this much current flowing through you, death is pretty much guaranteed. People never survive the electric chair. It’s not a hit or miss kind of thing.
The second way that electricity kills you is that it can get your heartbeat all out of whack. If your heart gets a shock it can go into fibrillation, where it gets its rhythm all screwed up and instead of making a nice beat it just kinda sits there and shakes. Your heart has kind of a funny design in that it is stable in the fibrillation state, so if you can get it screwed up, it stays screwed up. If someone happens to be standing next to you with a portable defibrillator, maybe you’ve got a decent chance of survival. Otherwise, you’re toast. Your heart shakes, it’s not pumping blood, you pass out, and then you die. It takes very little current to throw your heart into fibrillation. The shock that you got from your surge protector could have easily done it. You can very easily die from currents that don’t even come close to tripping the breaker. That’s why they invented GFCI’s.
Are you extremely lucky to be alive? No. People get shocked all the time and don’t die from it. Dying from a low level shock is very hit and miss. Your heart is particularly sensitive during certain parts of its cycle. Get hit with a shock at exactly the right time, and down you go. At other times during its cycle, the heart can handle a much greater shock without skipping a beat, so to speak.
The important thing though is that “low risk” and “zero risk” are not the same, and it’s your life you are playing with. Turn off the breaker.
Yes, there is still a danger. Heck, people have been killed by lightning while sitting on their toilets (what a crappy way to go). You don’t need to be in direct contact with a constant stream of water to get killed.
Remember, by the time lightning gets to you, it’s already passed through about a mile of thin air. A few more feet from the faucet to you isn’t going to make any difference at all.
The answer the that question may be a little suprising.
The amount of water is only part of the equation.
Also of great importance is:
your location in the water
the conductivity (!resistivity) of the water
what parts of your body are in the water
what you are touching while in the water.
If you are standing between the electrical source and the grounding path with your hands in your pockets, you may want the water to be very conductive for safety. If the water is highly conductive, the current will flow around your legs (rather than up one and down the other).
This concept is especially true if your head is underwater (say near a leaking light fixture in a swimming pool). Even very low voltages across the brain can dis-orient and cause drowning in water with currents flowing through them. The more conductive the water, the lower the voltage drop arcross your head.
If you are touching the grounding the path with a hand, say the metal cover on the water heater, you want the water to be as reisitive as possible to limit the current flow that will pass from your feet to the hand on it’s way past your heart.
If you’re standing in water, several feet from an outlet that is completely submerged, you should be OK regardless of the conductivity provided you keep your feet near each other and do not touch any thing with your hands. Would I be willing to back up this claim by joining you in the basement? NO WAY! Touching water that is touching an outlet is pure crazy talk.
Water can be a great conductor or not. I worked in a hotel. The parking lot had 480 vac lights. There were junction boxes in the garden area. The water table next to the bay was around 4 inches. If you opened a junction box it would be full of water with the wires and wire nuts under water. Never had a parking lot breaker trip or any short in the cristy boxes. I never stuck my hand in one of the boxes when the lines were live.
Electricty will take the shortest path (ie least resistance). If an outlet is under water and shorting the shortest path is from one side of the outlet to the other.
Also to give you heart problems the current has to pass through the heart, a shock from one leg to another will have little effect on the heart. Left hand to right leg is another.
I would never go into a basement with water over outlets until I turned the power off. If you touch a grounded object you may become part of the path. You never know.
I have read that the typical way you die from an electric shock that is not powerful enough to burn you up or blow flesh off your limbs is by suffocation because you can’t control your lungs anymore, and you can’t move off the wire, once your nervous system is being overwhelmed by the current flowing through you. It paralyzes you, in a practical sense, and if nobody comes along in a minute or so you die.
Why this problem doesn’t stop your heart and cause death sooner, I don’t know, but the heart does have local wiring that keeps it ticking, whereas your lungs don’t. Maybe that’s it.
Or maybe my information’s bad. I don’t remember its source.
I think most people would survive working in a basement while the recepticals get flooded. If “most” is good enough for you to trade it for the convenience of not turning the power off, have fun; but otherwise take the advice others offer and turn it off.
The house I grew up in had a wellhouse, an underground room about 7’ cubed. A pump sat on a concrete block a few inches above the floor, and there was an air compressor down there too. When the rain was heavy this room would flood and I would have to bail it out, filling buckets and lifting them overhead through the manhole to somebody above. In our house the wiring was done with black and white wires, but with no particular order observed for what was connected to the black and what to the white (since the recepticals had no grounding pins this is not surprising). Also, though I don’t remember about the well pump, based on more modern experience I would guess it was 220 VAC so both its supply wires were 120 V away from ground. I do remember how it often tingled to be down there, sometimes barely perceptable but sometimes strong enough to be really uncomfortable, sort of like a mix of sunburn and poison ivy and being weirdly exhausted from exertion. But it never got bothersome enough to drive me out (and living in the country without water would have been a big counterincentive). Since then I have wondered how close that chore put me to electrocution.
I guess another approach would be to go ahead with things like this, and then back up a couple of minutes if anything does kill you…
Right. I knew that, I just didn’t actually say it.
And whatnot is rather an understatement. That water was foul. (I got a tetanus shot the next day.)
The breaker, of course, is in the basement.
I do want to point out that had I been clear-headed, I almost certainly wouldn’t have been in the basement (at least, after I had saved the music scores and texts). However, I was a little overcharged with adrenalin; I almost drowned in the initial surge that flooded the basement, and it’s rather incredible what sort of focus that will give you. In this case, that focus was “save stuff” and “drain basement”. The electrical issue occurred to me, but I didn’t really care; I sort of figured it hadn’t killed me yet, so it was unlikely it would do so in the future. I did stay away from anything electrical or metal (except that damned surge protector, which I ended up throwing a ball at to turn off).
This is a popular misconception. Electricity does not take the path of least resistance. Electricity takes ALL paths. It’s just that more of it goes through the path of least resistance.
Leg to leg also goes through your torso. Part of the current will be going across your heart. Many people are killed by lightning even when they aren’t hit, just because the voltage gradient across the ground (as the lightning dissipates through the ground) causes current to flow up one leg and down the other.
That’s one possibility, but from what I’ve read your heart is usually your main problem.
There’s different types of shocks. At the lowest level, death typically occurs from your heart going into fibrillation. As the current increases, instead of going into fibrillation, the entire heart just contracts. This is still a problem, because while contracted it’s not pumping blood, but if the source of the current can be removed, the heart typically starts beating again and the victim usually survives. As you pointed out, though, if you aren’t able to move, you’re toast. At even higher current levels, you start suffering burn damage. It’s kinda odd but it means that often the intermediate voltages are more survivable.
I don’t have odds or statistics for you, but uncomfortable tingling is in the range of potential fibrillation.
For those who don’t want to click:
Guy standing on roof of train grabs electric train wire. BANGBANG He falls over dead and smoking, on the roof of the train. It was that quick, around a second. He might have been on fire, even.
