Customer getting shocked from bath tub

[aarifisher]

I have a customer that complaints about getting shocked from there bath tub.
When I got to the job I couldn't imitate the problem
So I checked the switch and the main panel.
All voltages was fine but there was poor grounding
I drove a new ground and regrounded the water main.

But customer still complains.

Can someone please direct me what else to check

 

[steve66]

I would suggest checking the voltage on the shower head and faucett and drains, and any other misc. piping.

If its got an electric water heater, I'd suggest checking that pretty well too.

I'm sure others will have more suggestions. Its important to fix this before someone gets really hurt.

 

[aarifisher]

this is an old house. not one i wired
also i didnt get any voltage at the time i was there

 

[raider1]

Also check out the main bonding jumper to ensure that there is a good connection between the EGC's and the Grounded neutral conductor.

Chris

 

[ptonsparky]

Had one customer that had to be in the tub and touching the faucet. Short of getting her to duplicate that process exactly make sure you get a good reference point for voltage measurements. Check for leaking water or damp areas that could be conducting current from.... just about anywhere. Bonding the drain lines now, if metallic, may just mask the problem now but make sure they are after you find the problem.

 

[philly]

Also check out the main bonding jumper to ensure that there is a good connection between the EGC's and the Grounded neutral conductor.

Chris

Are you suggesting there could be a ground fault that is not being cleared because there is no bond to the neutral and thus causing this voltage?

 

[ptonsparky]

You must use a meter to check for voltage. Work hardend fingers are not a good comparison with a wet body in a tub. Besides, not safe for you. Things could have changed just enough to make you another statistic.

Used my fingers to check voltage on a frig once. Figured that thinned skinned little old lady was exagerating. I'll never do that again.

edit: Did you mean to say that you did check for voltage? If so ignore this.

 

[quogueelectric]

Check for grab bars screwed to the wall with 3 inch deck screws penetrating a cable in the wall. This was always my electrocution favorite.

 

[qcroanoke]

Check for grab bars screwed to the wall with 3 inch deck screws penetrating a cable in the wall. This was always my electrocution favorite.

Had a friend who told me he was getting shocked when he grabbed some metal shelving
that had been there for years. After accusing him of drinking to much I tested the shelving
to ground with my Fluke and got 120 volts.
Found a 16 penny nail holding the shelving to the wall had nicked the hot wire. Shelving was isolated from ground so he never knew it till he touched it while barefooted.

 

[LarryFine]

this is an old house. not one i wired

That's a clue. It's possible there's energized metal lath behind the tile, or a shower door frame with a screw penetrating a cable. It could even be something on a switch in another room that isn't on when you're there.

also i didnt get any voltage at the time i was there

You have to find out what is energized that shouldn't be. You have a voltage between two points that "should" be at the same potential, but one of them is hot. What points are you measuring between?

You need a reliable reference point, such as at the main disconnect itself, where the neutral is bonded and the electrodes land. Use a wire from there to measure conductive parts and surfaces against.

Don't miss something like you're there during the day, but she showers at night, with the lights and fan on. In other words, duplicate her coditions. Ask her to show you how she turns on the water, steps in, etc.

Also, be sure to check the voltage between the neutral and both lines for a poor POCO neutral. A large 120v, load such as a heater, will create a larger imbalance. Ask if she's noticed changing light brightness.

 

[LarryFine]

After accusing him of drinking to much I tested the shelving to ground with my Fluke and got 120 volts.

Did you then accuse him of not drinking enough? :grin:

A non-contact tester would have shown that, too, and may in fact be the best sniffer for the OP to start with.

 

[kwired]

Old metal drain pipes usually are not bonded to electrical system, but the metal water pipes usually are. When a person is in the tub the water is at same potential as drain since the water is in contact with the drain, and when they touch faucet they will feel a shock if there is potential between them. In that case you may want to find out the source of the potential and correct it. You should also bond the metal drain pipe so it is the same potential as the water pipe.

If there is a small voltage like 3 to 5 it is probably just voltage difference between the neutral that is grounded in one place and the drain pipe that is in contact with earth in another - this is one reason why metal piping systems are required to be bonded together - If you have 120 volts between drain and water line proper bonding jumper would allow operation of overcurrent device that is energizing one or the other.

 

[gar]

100806-2232 EST

Larry gave you a very good suggestion to obtain a reference point from the neutral and ground bond at the main panel.

Very important to use a high input impedance meter, such as Fluke 27 or 87. Also check for DC, not likely, but make sure.

Any voltage difference over maybe as low as 100 millivolts between two points that could be touched by a person probably needs investigation. In this case the meter needs to be between the two points rather than taking the difference between two larger voltages. When the skin is saturated with water the resistance from the surface of the skin to an internal body point can be quite low. 100 millivolts and 100 ohms is 1 milliampere. That amount of current is detectable.

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