Stray current?

Discussion in 'Electrical Forum discussion & Blog' started by das108, Apr 2, 2011.

  1. das108

    das108 New Member

    Messages:
    23
    Location:
    DC
    Hi all:
    Hoping you can help put me on the right track here, but I know the solution does is unlikely to be DIY here. (You just helped me solve a simple upside down Moen cartridge)

    Lived in this condo for about 4 years. Noticed about a week ago that if i touched by stainless steel kitchen sink and the stainless steel front of my dishwasher at the same time I was getting a shock. Can't say I remember it happening before, and I am fairly sure at some time in 4 years I would have touched those 2 things at the same time. To be on the safe side, shut off the breaker for the dishwasher till I got it dealt with.

    But just now, screwing on a new shower head, I am fairly certain i got a mild shock from THAT.
    Again, have done some light plumbing in this place before and don't remember this happening.

    The pipes are copper through the building, much of it treated with epoxy Ace Duroflow because of a pinhole problem. Building is circa 1968.

    My instinct is that this is a building problem, and someone has changed something or such.

    Anyone else have thoughts on if this is likely in my unit, vs a a greater problem that the building should be looking into?

    Thanks a ton.
    David
  2. jwelectric

    jwelectric Electrical Contractor/Instructor

    Messages:
    2,566
    Location:
    North Carolina
    This could be due to multiple reasons. I would recommend that you have someone look at your unit to establish if it is your unit or something that the association should address.
  3. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    22,325
    Location:
    New England
    Could be something like someone put up a picture, sank a nail, and hit something they shouldn't have. Could get nasty finding it. This is one reason why in most places, a homeowner of a multi-family dwelling isn't allowed to do stuff that he could if it was a single family dwelling...there's too many other people that could be affected.
  4. das108

    das108 New Member

    Messages:
    23
    Location:
    DC
    Unfortunately that's pretty much what I expected....it could be anything, anywhere, and will likely be a fiasco to figure out.... thanks for the wisdom...
  5. LLigetfa

    LLigetfa DIYer, not in the trades

    Messages:
    4,185
    Location:
    NW Ontario, Canada
    If all is working as it should, the metal of the door is connected to the protection ground. Turning off the breaker would not change that. If the shocks ceased by turning off the breaker it might suggest a fault with the wiring or dishwasher.

    It would be interesting to know what other conductive material you were in contact with at the time to help understand what two points held a voltage potential.

    Years ago, a friend's starter blew on his car which was parked under high tension power lines. I was helping him to change the starter. He was laying on the ground under the car, complaining about getting shocks, and insisting that I had not disconnected the battery. The battery was disconnected and the shocks were coming from the voltage induced by the overhead powerlines. The rubber tires were insulators and he was completing the circuit to earth ground with his body.
  6. das108

    das108 New Member

    Messages:
    23
    Location:
    DC
    Well with the showerhead, I was standing in my fiber-glass tub and had both hands on the showerhead/pipe. There may have been a little residual water around my feet and its not impossible i put a toe on the drain, although it seems unlikely based on the angles of things.
  7. LLigetfa

    LLigetfa DIYer, not in the trades

    Messages:
    4,185
    Location:
    NW Ontario, Canada
    Was it a single hit like a static discharge, or a lasting tingle? Did the shocks at the dishwasher cease? The voltage potential source could be outside your apartment and the potential difference could be intermittent making it very difficult to track down. It helps of course if the tests are repeatable.

    I have seen where the neutral to a building was open and the copper plumbing was providing the return. There was enough current carried by the pipe that it warmed the water a bit. The current/voltage potential difference was enough to blow circuit boards.
  8. ballvalve

    ballvalve General Engineering Contractor

    Messages:
    3,261
    Location:
    northfork, california
    Next time you drive under large transmission towers push the button your voltage sensor - lights up like a xmas tree!

    Have to wonder what it does to pacemakers.

    And for the guy with the hot plumbing - your next shower might be like the ones the germans gave in 1939 through 1945.
    Last edited: Apr 4, 2011
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