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Thread: Electrocution From Kneeling

  1. #1
    Join Date
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    Electrocution From Kneeling

    As I was performing an inspection I came across a few outlets on the back of the house near the water pumping system. The house was destroyed by the home owner when he was forced to leave the property due to forclosure.

    The outlet wweather box seals were not intact and water had been in them for quite some time. The GFCIs didn't work and no voltage present with all breakers on. I notice a switch on the wall heading to the water pump switch and I removed the cover and bugs came pouring out of the liquid tight, and it was energized @ 240V.
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    Once it left the water pump switch the LT went underground somewhere. 40 feet away I could see a wooden post with a junction box mounted to it and that flex pipe going into it. I put my fluke on voltage alert to the side the box and get nothing. I then remove the cover and 0 Volts. Hmmm..what is going on here?
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    I left it alone and then continued. As I moved through the side of the building the ground was becoming more moist as the rain collected there it seems. As my boot slid I turned around and saw another wooden post about 25 feet away but the LT was not going into the junction box. It came out of the ground and then arched over back into the ground. I was getting ready to kneel by it to inspect it but I decided to shut the entire main to the abandoned house off. I picked up the LT pipe and the conductors were burnt to a crisp. It appears that they were arching together while in the dirt.
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    I capped the wires, turned on the power and 240V present. Would anything have happened if I kneeled next to this pipe? Is there a method to perform a voltage check on the actual ground, not the ground conductor?
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  2. #2
    Join Date
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    Wow, a pressure switch with the EGs connected to it!

    is it safe to assume that the EG was also sticking into the earth along with the Hots? Most of the current would have been flowing between those three conductors.

    Your system is 120v to ground so that is the max exposure you would have had and that would mean touching one of the hots directly.

    Meassuring the step potential is possible with a meter but it tells us only the voltage between the leads. How much do you weigh? Are you wearing E rated boots? Bare knee? Did your hand touch the ground on the way up/down? What is the soil type? Male/female? That and more will determine if you would have felt a shock had you kneeled.
    Tom
    TBLO

  3. #3
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    The part that is going into the earth only L1 and L2 were present. No grounded conductor was attached on the end and my assumption is that it may have been ripped out with some force as its not inside of the tubing.

    To clarify: If the EG was present and also into the dirt, this would prevent a shock from happening and the most I'd experience is some arcing between the wires. However, If no ground is present, I am susceptible to step voltage?

  4. #4
    Join Date
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    Quote Originally Posted by Cybatrex View Post
    The part that is going into the earth only L1 and L2 were present. No grounded conductor was attached on the end and my assumption is that it may have been ripped out with some force as its not inside of the tubing.

    To clarify: If the EG was present and also into the dirt, this would prevent a shock from happening and the most I'd experience is some arcing between the wires. However, If no ground is present, I am susceptible to step voltage?

    a
    anything could happen in the perfect storm
    CircuitRyder --- Unfortunately not all good ideas are code enforceable.

  5. #5
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    Quote Originally Posted by Cybatrex View Post
    .....To clarify: If the EG was present and also into the dirt, this would prevent a shock from happening and the most I'd experience is some arcing between the wires. However, If no ground is present, I am susceptible to step voltage?
    Check out this sticky over in the Grounding vs Bonding section of the forum - http://forums.mikeholt.com/showthread.php?t=95495
    If Billy Idol or John Denver is on your play list go and reevaluate your life.

  6. #6
    Join Date
    Dec 2007
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    Most of the time you wouldn't get shocked, but there is always that one time when conditions are just right and you do.

    Soil moisture and conductivity as well as where you make contact within any voltage gradient present is what will determine how much voltage is present and between what points. If it had been energized before you got there, any current flowing will tend to dry out the soil around the primary contact point with the conductor(s) and increase resistance at that point - which will lessen shock potential.

    There will be voltage "zones" in the earth in circular pattern around this fault to earth. The narrower those "zones" are the more voltage you will be able to reach across and make contact with.

    Those zones are typically much larger for 120 volts then for 7200 volts though, which is why they tell you to shuffle or hop and not to run away from downed high voltage lines so you don't make contact across too much voltage between feet.

    Short answer - it depends.

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