electrical engineers.. a question!

Discussion in 'Shop Talk' started by comfortablynumb, Oct 3, 2004.

  1. comfortablynumb

    comfortablynumb Well-Known Member

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    We have had some biggie floods around here and I have a question on behalf of even a few electricians who honestly dont know the answer (how being electricians they dont, i dunno)

    ok, we got flood water... filled basements and first floors, service panels under water....
    power still on, and when they pump the houses out often the lights are still on UNDER water.
    I was chatting with an electrician who was telling me about how he was drying out a house, he yanked the meter, was downstairs cleaning the panel and the power guy came by and put the meter BACK.... to which he told him to yank it they were drying the panel out.

    I ask em "why doesnt everyone get fried dead if the panels have power and they are under water? "
    well that stumped him... he and his buddy had various electician talk on why maybe it was so but no explinations... his bud said he didnt know why, in that situation the transformers wernt exploding from all the short cuircuts.

    another friend of mine is activly pumpling out basements and said it isnt at all unusual for the lights to be on under water, he doesnt know why no one is getting fried either...

    toss a hair dryer in a tub, you get boiled.

    submerge a live 200 amp service, and nothing happens, and the power remains flowing even under water.

    why?

    yes a lot of homes lose power, a lot of transformers have gone kerpowie... but whole towns here are submerged and A LOT of this power on/live panels/under water/ no electrocutions are being seen.

    standing in a foot of water, cleaning a live panel when they put the meter back in he should have been cooked to death... he wasnt, the lights were on and no one can explain why.

    I myself saw submerged lights on and people wading thru water not 25 feet away. there had to be a submerged HOT line nearby.

    explinations???

    ive seen news stories here of downed power lines and people getting killed stepping out of their cars on wet pavement.... so hot lines near water = dead meat but.. not always??

    this is a real quizzer..
     
  2. moopups

    moopups In Remembrance

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    My opinion (and its opinion only) is that electricity will follow the easiest path, the panels are complete circuits, those who get zapped do so when they themselves do complete a circuit by comming into contact with a live wire.
     

  3. Maybe everyone is wearing rubber suits! :D
     
  4. comfortablynumb

    comfortablynumb Well-Known Member

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    aww come on someone has to have a real answer to this one....

    your basements flooded and your lights are on under water and your service panel is under water, why aint you getting boiled alive when you are in the water too??
     
  5. aaatraker

    aaatraker Well-Known Member

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    I'll give it a shot, not all water is equal, pure water {no mineral content}
    is a very poor conductor, flood water I would have thought would have a high content, but there are so many varibles. What the person is wearing what they touch to become part of the circuit. Thats why electricty is so dangerous. It doesn't do what we think it should, when it should. And if the water doesn't make a circuit between hot conductors for a phase short or to ground for a ground fault then the powers on until it does. You never know when that will occur, thats why water and electricty is so dangerous.

    I worked on a test machine that used water under pressure, a cycle counter, and a electrical solenoid, to cycle water valves for endurance
    tests. The valve was in a sealed glass container, the counter was use to cycle count how many times the valve was hit with water pressure before the seals broke. The glass container had a open circuit on the bottom, so that when the water filled the container, the circuit would make and stop the counter. We used tap water , no circuit, added salt no circuit, add sea salt no circuit, added iron no circuit. Finally, I think { its been fifteen yrs and lots of projects since} we added copper sulfate to the water and we got the circuit to make. You were encouraged to be Mr Wizard, , Macgyver and the plant electrician at that company, had a great time!!! Not sure this helps, but its my experience with water and electrons. Electricty is wierd stuff!!!!!

    kurt
     
  6. comfortablynumb

    comfortablynumb Well-Known Member

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    in some places the flood hit the panels and the transformers exploded along the street like fireworks, other places the power was on in hot panels under water for days with the lights on underwater.
    the ground for miles was saturated, perhaps it was such a good conductor the flow was undisturbed and bled off into the ground and disipated the charge to the point it just wasnt felt?
    I dunno if thats even possible.... it was wierd.
     
  7. mary,tx

    mary,tx Well-Known Member Supporter

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    Let me give a try from what I remember from chemistry class many many years ago... (I may also have a few errors in my description, but here goes....) Go ask a chemist not an electrician for the most accurate answer.

    aaatraker almost has it right (note that salt water will conduct--in theatre years and years ago, they had "salt water dimmers" that employed a wooden paddle with a conductor lowered into a tub of salt water).

    PURE water does NOT conduct electricity. Salt water (there are several kinds of salts, not just table salt which is sodium chloride) and water with certain disolved minerals does. The disolved salts and minerals are in solution as ions (for example, sodium with a positive charge and chloride with a negative charge) and have the capability to transport electrons (supporting the flow of electricity). Molecules that do not dissolve into ions do not cause the water to conduct.

    Water from the water supply or pumped from underground will usually have disolved salts and minerals in varying amounts. If the flood is from rain water, it is mostly pure and therefore mostly a poor conductor (if it is not 'polluted' from other sources of ions).

    Now, do NOT attempt fate just because the power still flows in the conductors. NEVER expect the water to be pure enough to protect you--there will be some level of conductvity. There are lots of things that can be easily disolved that will make the water conductive.

    [Homeschool lesson: flashlight bulb, wire, glass, distilled water, and various things to disolve in the water.]

    Dale (dh of mary, tx)
     
  8. aaatraker

    aaatraker Well-Known Member

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    Lets assume that in every case there is enough disolved solids, salt and minerals in all water, to conduct current when it comes to electricity. And you treat it as such!

    Assume= I'll take the chance of making an ass out of you and me if we both stay safe with that thinking.
    kurt
     
  9. gspig

    gspig Well-Known Member

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    Whether you are or aren't fried in electrified water depends on your location to the current source. You won't get fried if you aren't part of the circuit. You could hang on a high power supply wire as long as you don't touch anything but that wire. The electrician could have been fried, but he must not have been touching a live contact when the meter was plugged in. As for the lights staying on, as has been already said, the water must not have been conductive "enough" to carry enough current to short out breakers.