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Posted By: aldav53 Shock from shower fixture - 07/16/03 03:00 AM
Went on a repair and the customer said he got a shock off the shower fixture. I tested to see if the water pipe for it was grounded and was getting weird ohm readings. Found later that someone replaced part of the water pipe in the attic with a PVC type which isolated half the water pipe from ground. I ran a #4 ground wire to connect them which grounded it. But not sure where the voltage was getting picked up in it before. Maybe through inductance from wires crossing over it? The customer said he got a good shock off it when he touched the shower head and the metal edge on the shower door. (The shower door edge was not tied to ground at all). Kinda strange.
Now that the shower water pipe is grounded there should be no way it can become energized. Any opinions on what might have happened and whether its completely safe now?
Posted By: pauluk Re: Shock from shower fixture - 07/16/03 09:03 AM
Were there any cables running near and parallel to the pipes in question? If so, then the shocks could have been a result of capacitive coupling. It wouldn't take a lot of capacitance to result in a noticeable tingle to somebody standing wet in the cubicle.
Posted By: PCBelarge Re: Shock from shower fixture - 07/16/03 11:17 AM
About 2 years ago a local man was killed in his shower. The culprit was the shower rod, which had long screws anchoring it, and one of those screws had pierced a cable and was energized. Maybe you should take a reading between the shower door and the cold water/drain pipes.

Pierre
Posted By: james S Re: Shock from shower fixture - 07/16/03 12:55 PM
I guess its possible for the induction theory but would need single core cables (maybe lighting) to be able to induce any voltage into the pipe.

as for the shower door edge there might of been damp in the walls enabling tracking voltage within the walls. i have found 240 v on damp walls due to faults in sockets and switches before !!!!

just an idea thats all [Linked Image]
Posted By: aldav53 Re: Shock from shower fixture - 07/16/03 03:20 PM
Pierre, I did take a reading at the shower door from the ground at the bath recept and it was isolated, no reading. But the damp wall thoery from james S is possible.

(Did not see any cables near the water pipe in the attic).
This one has me baffold..
Posted By: golf junkie Re: Shock from shower fixture - 07/17/03 01:04 AM
FWIW.....I have seen a case where an ungrounded electric water heater was shocking people when they touched the shower nozzle.

GJ
Posted By: aldav53 Re: Shock from shower fixture - 07/17/03 05:08 AM
I probably need to run a ground wire to the shower frame too. Just in case the frame did become energized somehow.
Posted By: kale Re: Shock from shower fixture - 07/17/03 06:43 PM
I've received a shock from a tub faucet caused by shorted well pump, and this was after the metal pipe had run through the ground several hundred feet and was bonded. So I no longer trust that grounding a pipe will stop the current from being felt.
Posted By: aldav53 Re: Shock from shower fixture - 07/17/03 07:34 PM
Kale,
Current takes the path of least resistence and unless you have a good ground it may take another path.
Posted By: PCBelarge Re: Shock from shower fixture - 07/18/03 12:21 PM
Another thought.
Check for a subpanel. If there is one see if he grounded the panel to a pipe and did not properly ground it back to the source where the subpanel receives its power.

Pierre
Posted By: condenseddave Re: Shock from shower fixture - 07/18/03 05:11 PM
I ran into a bathroom sink in a grocery store a few years ago, where the faucet was connected to the main plumbing with those flexible polybutylene lines.

The faucet was causing a rather painful shock.

Never really found out why it was becoming energized, though. A #12 jumper from the CU to the faucet itself stopped the shocking, though.

I often wondered how that was possible, as the faucet was connected only to the porcelain and the PB water hoses.

What are the chances that it was being conducted by the water in the piping, rather than the piping itself?

Doesn't make sense. The water supply was "city water", and there was only one faucet out of about twenty (throughout the store) that was effected.

The building was only a few years old, and there was never any shocking problems from anything else in the place...

Things that make ya go "HMMM".
Posted By: aldav53 Re: Shock from shower fixture - 07/19/03 06:03 AM
condenseddave, Yep, I know what you mean, can be very frustrating not finding out why.
Posted By: resqcapt19 Re: Shock from shower fixture - 07/19/03 05:53 PM
aldav53,
Quote
Current takes the path of least resistence and unless you have a good ground it may take another path.
Current takes all available paths, the amount of current on each path is inversely proportional to the impedance of that path.
Don
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