1000 ways to die - electrified basement water

Discussion in 'General Electronics Chat' started by strantor, Jun 8, 2011.

  1. strantor

    Thread Starter AAC Fanatic!

    Oct 3, 2010
    4,302
    1,988
    Ever seen that show 1000 ways to die on Spike channel?

    I saw an episode the other day where a couple of girls were killed by walking into a flooded basement, where an electrical outlet had been submerged. Is this possible? I'm thinking that if the outlet was submerged (first off, the breaker would probably trip, but if it didn't...), current would just flow from L to N inside the plug (or through the shortest distance of water to the nearest ground) , and the water would be safe. In my mind, I can't see the current flowing out through the socket, across a room full of water, up through a leg, torso, heart, and back down through the other leg, back across the water, and back into the outlet. The only way you should get electrocuted is if you complete a circuit, which you shouldn't be able to do by standing in a flooded basement with a flooded outlet. They showed a regular 120v outlet and then their "expert" - a 20-ish blonde chick said that there was 440V passing through their hearts.

    BTW, don't their "experts" seem a little fishy? they always seem underqualified, or they just plain don't state their qualification.
     
  2. Wendy

    Moderator

    Mar 24, 2008
    20,766
    2,536
    I've watch the series, and have the same opinion. I've seen some of the stuff they claim has happened on MythBusters, and it didn't pan out. I suspect the writers of this series take a lot of liberties with the show.

    I wouldn't want to try walking in potentially electrified water, but I tend to agree with your assesment.
     
  3. strantor

    Thread Starter AAC Fanatic!

    Oct 3, 2010
    4,302
    1,988
    yeah, like the guy who pee'd on an electric fence and his junk blew up
     
    #12 likes this.
  4. tom66

    Senior Member

    May 9, 2009
    2,613
    214
    In any event, the GFCI should trip if there is a significant live-earth or neutral-earth current flow, which would probably be caused by water.

    I measured the resistance of water to be quite high, actually. A cup full of tap water from end to end measured 40k ohms. I imagine a basement full of water (assuming nothing tripped) would tingle at 10's of megohms, but not kill.
     
  5. strantor

    Thread Starter AAC Fanatic!

    Oct 3, 2010
    4,302
    1,988
    This supposedly in an old historic church basement in new orleans after katrina, so highly possible there was no GFCI
    I also have done experiments on the resistivity of water as part of an issue I had at work, where we dunk spools of wire in a pool of water and megger them to check for pinholes/current leakage. in my initial testing with a DMM I encountered the high resistance (into the megohms for long distances) as you mention. I setup a chart and measured from all distances across the pool and everything. All of that data went out the window when I did the same testing with a megger. I don't know if you would call it "breakdown voltage" or what, but at higher voltages, the water acts as a direct short, not even able to be measured by the megger, which has a minimum range of 100kohm, so it should have agreed with the DMM in the lowest range but it didn't.

    ALSO, assuming this might have been salt or brackish water, resistance would be even lower.
     
    Last edited: Jun 8, 2011
  6. lightingman

    Senior Member

    Apr 19, 2007
    374
    22
    Water in a basement will conduct electricity, as the salts come out of the eath and concrete. We had a flood in our main power room. The 415 volt, 3 phase, 600 amp bus bars were under 15 inches of water. There was no effect for about the first 30 mins, then lots of small bubbles apeared from the concrete floor. Slowly the water started to conduct and heat up, until it started steaming. Then we shut the whole thing down. Once it had all dried out it was fine, and is still ok now.

    Daniel.
     
  7. strantor

    Thread Starter AAC Fanatic!

    Oct 3, 2010
    4,302
    1,988
    Interesting!

    Do you think you would have been electrocuted if you were to walk into the water? My theory is still no; since the water is a conductor, and you are merely on/in the conductor, you won't be electrocuted, just like birds aren't electrocuted sitting on power lines. Unless you provide a lower resistance to ground (through your heart) than the water (which I doubt) then you should be safe I would think.
     
  8. tom66

    Senior Member

    May 9, 2009
    2,613
    214
    You're more likely to be burnt from the boiling water than the electricity; which could be the reason they were reported as electrocuted. Both would cause similar burns.
     
  9. CD-RW

    Member

    Feb 26, 2011
    33
    1
    I don't watch TV, but would this depend on the height of water, and how high the mains feed is, for it to go to ground?
     
  10. strantor

    Thread Starter AAC Fanatic!

    Oct 3, 2010
    4,302
    1,988
    well, the reenactment that they showed (which porbably was not accurate) showed a 120V outlet mounted in 4" metal box, with conduit attached to a concrete wall, about 2ft off the ground. considering the wall is underground, i would assume that it is ground and the current would need only to travel about .5" inside the box... but we will never know the true details of it i guess
     
  11. CityguyUSA

    New Member

    Sep 12, 2013
    1
    1
    I've done the basement walk of shame. I didn't even think about getting "zapped". This was after Flood Lee in 2011. I had 23" of water in the basement. The dehumidifier, the furnace blower motor and circuit board, the freezer compressor and on/off indicator and the shop vac all under water.

    It was after I had walked into the water and I looked at the dehumidifier floating like a buoy that I was like what the hell, how is this possible? Why am I not getting shocked at the very least?

    No one has been able to explain it to date. But what I'm reading here is that the water is a better conductor to ground than I am and therefore it's just kind of a lucky rule of grounding. Is that right? What I don't get was I seem to remember that the freezer light was on even under water which was how I knew that the breaker hadn't shutoff. But why was the light still lighting rather than shorting?

    This all leads to my second question of why when you're in the ocean and somewhere in the world there's a lightning strike that hit's the ocean why don't we all float up to the top like dead fish? Is there just too much water causing the current to be so dissipated that there's no energy left to electrocute us? If that's true would being closer in proximity to the strike have a different outcome?
     
    shortbus likes this.
  12. MaxHeadRoom

    Expert

    Jul 18, 2013
    10,548
    2,373
    The was a recent article on the lightening phenomenon, and it is discovered that as electrical conditions that harbour lightening storms travel above the earths surface, there is a opposite charge in the ground that follows it as it moves along and when the charge has reached sufficient level, the flash over occurs.
    I did some low level tests with 24vdc on some circuit terminals that were exposed to tap and river water, even at 24v it can be quite conductive for semiconductor circuitry.
    Max.
     
  13. strantor

    Thread Starter AAC Fanatic!

    Oct 3, 2010
    4,302
    1,988
    I
    it's ironic you should dredge this up now, as I was just thinking about it yesterday. I was thinking, technically a brushed dc motor should work under water, though I've never tried. My thinking is, yes, there is a new current path from brush to brush, but at low speed, the armature is probably still the lowest resistance path, so it should still turn. If it were driven by a dc motor drive, the drive would probably go into current limiting early, but for example if it were for an ebike or egocart, as long as you went slow to prevent high counter emf, you should be able to drive through water with the motor submerged.

    In answer to your question, is similar to my hypotheses about the dc motor. Under water, the current has a new path(s) around the bulb, but the bulb is probably still the lowest resistance path, so it still carries the bulk of the current and still works despite being submerged. This would probably hold true in most water except salt water; just more guesses. You're welcome to experiment.
     
  14. PackratKing

    Well-Known Member

    Jul 13, 2008
    850
    215
    1000 ways also once had a feature about this pizzed-off chick that threw either a fan or a heater into the bathtub with her sig-other, and supposedly he was zapped....
    Makes more sense than the basement scenario...
     
  15. #12

    Expert

    Nov 30, 2010
    16,298
    6,811
    Just a note on water conductivity. I used to work in a place that designed and built conductivity meters (and a bunch of other water quality measuring devices). I learned that deionized water is so clean that you can't light a neon bulb through an inch of it with 120 VAC. I know because that was what they used to tell when the deionizing tank needed replacing. If bulb lights, water is not completely deionized.

    At another moment, I was supposed to test a conductivity meter, with no training, of course. I was barely getting a flicker on the available scale, so I cautiously stirred the glass of water with my finger and the conductivity went up by 1000x.

    The moral of the story is that really clean water is a very good insulator and it only takes a tiny bit of dirt or sweat to change that drastically.
     
    strantor likes this.
  16. #12

    Expert

    Nov 30, 2010
    16,298
    6,811
    And about lightning...it disperses. Lots on the interwebs about it. Point of contact: sand turns to glass. Nearby, 10,000 volts per meter as the current disperses through the soil. Stand on one foot and your wet tenny starts steaming. Two feet down, a golf club apart, and your junk starts steaming.:eek:
     
  17. DerStrom8

    Well-Known Member

    Feb 20, 2011
    2,428
    1,328
    No, if the water is high enough to reach the live prong of the socket, it's also high enough to reach the ground and/or neutral leads. It doesn't matter how high the outlet is.

    Strantor, I'm with you. Total bull crap.
     
    strantor and #12 like this.
  18. strantor

    Thread Starter AAC Fanatic!

    Oct 3, 2010
    4,302
    1,988
    How much contamination does it take to transcend the boundry between DI water and tap water, and further, water that can rival a copper conductor? My crude findings with crude criteria indicates that it takes a huge amount of salt to make water anywhere near as conductive as wire. IIRC it took more salt than water in a glass of salt water to be conductive enough to replace a wire in a circuit consisting of a 12vdc power supply and a 12 vdc relay coil to make it switch.
     
  19. wayneh

    Expert

    Sep 9, 2010
    12,127
    3,048
    While we're on the topic - which I find fascinating - I think you'll all agree a toaster in the bathtub is a more likely hazard than an outlet across a flooded room. But still, if you're not actually touching the conductors, and you're no better grounded than anything else in the water, is a toaster in the tub really a guaranteed electrocution like they show in the movies?
     
  20. #12

    Expert

    Nov 30, 2010
    16,298
    6,811
    Cut the third prong off the cord, reverse the conductors so the case is hot, and holler, "Catch!".:D
     
Loading...