slight electric current from shower head

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Old 09-04-09, 02:43 PM
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slight electric current from shower head

As strange as it sounds, when I adjust the shower head, I feel a very slight electrical current. There has been no electrical work done in years. Where should I start and how does one diagnose the electrical short? Thanks, JB
 
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Old 09-04-09, 02:45 PM
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Do you have an electric water heater. Do you have an analog multimeter?
 
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Old 09-06-09, 10:25 AM
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This would be an "advanced" electrical troubleshooting problem. And can be quite dangerous to troubleshoot!

I would recommend hiring an electrician.

Basically ask the electrician to...

Find the source of the leak to ground...

Any grounded appliance could be the cause of the leak to ground. Grease/dirt in an electric motor, a stray wire touching the frame of the appliance, etc. This would place a hot voltage on the entire ground system!

Turn off all breakers and using a multimeter to a good ground, see if the problem goes away.

Turn on one breaker at a time and see if it returns.

If one breaker does this, turn off, then turn on all others to see if it is just that one breaker.

Then see what is on that circuit and check each appliance.

Some appliances like an electric hot water heater may only be on when making hot water. So run the hot water so it will activate. There is an upper and lower heating element. When the top has reached the set temperature, the lower element will activate. Cold water goes into the bottom of the tank. Mostly just the bottom element runs. So need to run the hot water for quite awhile to get the top element to kick on. The heating elements can sometimes leak to ground.

Another way to measure this is test the shower head for voltage to a ground. Before shower see if no voltage, then see how long it takes for the voltage to show on the meter. If quickly, then bottom element is suspect. Takes awhile, then top element is suspect. And if no voltage when water heater has had a chance to warm up for several hours, and voltage when running hot water, then hot water heater has a problem!

There is "resistance" in electrical wire. And there would be resistance in the ground wires going back to the main panel. So basically the leak to ground voltage would be a bit higher closer to the source of the leak. Therefore testing various water pipes with a multimeter with one lead connected to a good ground (and the SAME ground for all tests - long wire to ground source) might show a higher voltage in a particular location. This would be closest to the source of the electrical leak. (Another clue.)

Check your grounds...
Two ground rods placed 6 ft. apart at the main panel is good.
Cold water pipes bonded to ground.
Hot water pipe bonded to cold water pipe.
Metal gas pipes bonded to ground.

If you have a water meter, a ground jumper around the meter is good. Some water meters have rubber grommets and will isolate the ground connection from the house side to the street side. If there is plastic pipe run to the house, this would be useless.

Look for plastic pipe added to the plumbing. There may be "isolated stretches" of metal pipes. Be sure these are bonded to ground.

Checking the grounds with the power on can be dangerous! Especially repairing/disconnecting/connecting main grounds or adding bonding wires to metal pipes, etc. A malfunctioning appliance may be placing a hot voltage on a pipe and a poor ground is keeping that pipe near ground potential. Removing the ground may cause the metal pipe to float up to full hot potential! If you then touch the pipe, you could be electrocuted!
 
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Old 09-06-09, 11:35 AM
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Originally Posted by Bill190 View Post
This would be an "advanced" electrical troubleshooting problem. And can be quite dangerous to troubleshoot!
Why dangerous, if the person followed your excellent instructions and did the tests involving one circuit at a time? That sounds like a really good tip to try to find if isolated to one circuit, then find the source within that circuit.
 
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Old 09-09-09, 03:21 PM
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thanks to all that responded. I called an electrician and he suspects the lower element in the electric water heater is bad since the slight current is intermittent and coincides with the water heater turning on and off. He disconnected and cleaned the grounds. I'm replacing both water heater elements. Thanks Again, JB
 
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Old 09-09-09, 04:00 PM
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Thanks for letting us know.
 
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Old 09-09-09, 07:56 PM
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An interesting story for you. Back when I was in electrical school a friend of mine asked me to go over his house and look at something. He said that for years and years and years every time he took a shower and backed into the spigot he felt a little jab. He always assumed it was a sharp point on the metal. But when he looked for the edge he couldn't find it. After some out-of-the-box thinking he grabbed a small piece of wire and a flashlight bulb and strung the bulb between the spigot and the drain and the bulb lit up. Then he went under the house and took an amperage reading on the main water pipe and got something like 4 amps. So he called me to go in the panel and find the problem. Well I found the problem, but it wasn't in the panel. It was on the roof. He had NO neutral. The neutral from the pole came to the house ... and ended there. It did not go down into the meter. I told him this and that he should get it fixed and he said, "ok," and left it alone for ten years.

Fast forward and the town was working in the street on the water pipes going to his house and someone got shocked. They called LIPA and had the power shut down. They wound up running a neutral for him and the current on the water pipes was gone.

His father had built the house in the fifties and I guess electrical installation wasn't something they taught in the police academy.
 
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Old 09-10-09, 07:41 AM
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another thought

Take Bill190's advice first because that seems like a good way to isolate the problem. I just wanted to add one thought though. I've lived in some older houses that didn't have grounded outlets, and talked to various electricians about adding a ground wire. Although it is technically against the NEC, some people have suggested running a ground wire from an outlet to a nearby water pipe. It's possible that someone did this in your house prior to your residence there, and there's a faulty appliance which is causing a current to be running to the water pipe which happens to be connected to your shower head.

Also if you do find out, let us know - I'm curious.
 
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Old 09-10-09, 09:18 AM
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Originally Posted by bachrach44 View Post
Take Bill190's advice first because that seems like a good way to isolate the problem. I just wanted to add one thought though. I've lived in some older houses that didn't have grounded outlets, and talked to various electricians about adding a ground wire. Although it is technically against the NEC, some people have suggested running a ground wire from an outlet to a nearby water pipe. It's possible that someone did this in your house prior to your residence there, and there's a faulty appliance which is causing a current to be running to the water pipe which happens to be connected to your shower head.

Also if you do find out, let us know - I'm curious.
Why do you say thats against NEC code? Which code would that violate?
 
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Old 09-11-09, 06:08 PM
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And to add to nickdel's post - I have felt electric current so miniscule coming from some appliance to my own body, that I can only feel it when an open cut on me touches the metal. I have always found such causes, and never disregarded them, always figuring the problem may get worse, rather than better on it's own.
 
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Old 09-11-09, 06:44 PM
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Two things, the grounding wire should only be carrying current in the event of a fault.

Secondly the Code compliant methods for grounding receptacles are spelled out in 250.130(C). Water lines are not listed in the choices.
 
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