shocked while in the shower

[Coastalguy1]

I have been asked to troubleshoot the reason why a friend is getting shocked whenever they touch the shower head pipe. Also gets a tingle when touching the metal soffit around the house.:? I believe it to be a loose building ground. Any thoughts?

 

[don_resqcapt19]

... I believe it to be a loose building ground. Any thoughts?

It is very unlikely that a poor connection to the grounding electrode or even the total lack of a grounding electrode would cause this.

 

[Dennis Alwon]

Is the metal soffit grounded or energized?

 

[hurk27]

Sounds more like a bad neutral connection or the transformer has lost it's primary neutral connection.

Is it a pad mounted or pole mounted? If pad mounted you can check to see if there is voltage to earth on it, pole mount the POCO will have to do it.

is the transformer fed from a delta or Y system? Delta primary will use a two bushing transformer, Y will have a single bushing, delta is not subject to this type of problem.

Measure the voltage from the meter can to earth and or if pad mounted transformer measure the voltage from the transformer case to earth, if you have above 10 volts I would call the POCO if it is not a problem in the main panel, but check out the neutral as much as you can on your end.

 

[ptonsparky]

Piping systems not bonded properly. Possible loose neutral either POCO or at service. This could be a neighbor's or a neighborhood problem. Ask the neighbors if they are having problems.

 

[renosteinke]

I have addressed similar situations twice; the key here is to be systematic - don't guess.

First determine the source of the power. You do this by turning breakers, even the main, off ... untill the problem goes away. Now you know exactly what part of the system is at fault. Now you can begin to take that system apart until you find the issue.

You also need to review the return path to the electrical service. That is, your grounging of the circuits and the panel case, your water bond, and the ground / neutral bond in the main panel. While a bad (or missing) ground / neutral bond will not cause your problem, it will prevent breakers from tripping - leaving things energised.

My two instances?

One was a trailer with 'live' siding. There was no neutral / ground bond. A short to ground was caused when a nail in a piece of metal tub trim pierced the wires under the wall.

The other was an extension cord in the bathroom. The end of the cord was sitting in a puddle next to the tub, concealed by the shower curtain.

Perhaps it is simple chance that both of these problems were in the bathroom. Perhaps not. I don't know.

 

[kwired]

You need to figure out what it is you have potential between, and then find the source of the voltage.

Maybe there is something common between the metal soffit and the water piping but is not bonded to electrical system ground.

One of the last times I had a problem in a tub or shower they were getting shocked only when they were in the tub and when they touched the water faucet.

I found I had voltage (don't recall how much, maybe only 10VAC max) between the faucet and the drain.

Water piping was bonded to electrical system, drain piping was metallic (it was an older home) and was metallic into the ground, but it was not bonded to electrical system. So this put drain pipe at earth potential, and water pipe at service neutral potential. Any voltage drop on the neutral (as well as the POCO neutral which is bonded to the secondary neutral) would show up between the two points. After some additional checking I was pretty sure the neutral connections were fine and that some of the voltage was likely coming from voltage drop on POCO neutral as I still had voltage with service switch opened. Bonded the drain piping to the electrical system and never was called back.

 

[K8MHZ]

My sister had the same problem. It turned out that the metal in the water pipe was not bonded anywhere. This was an easy fix, I just bonded the pipe above the panel which was only a few feet away. Problem solved. Now both the drain and the shower head are at the same potential and there is no more tingly sensation.

 

[don_resqcapt19]

My sister had the same problem. It turned out that the metal in the water pipe was not bonded anywhere. This was an easy fix, I just bonded the pipe above the panel which was only a few feet away. Problem solved. Now both the drain and the shower head are at the same potential and there is no more tingly sensation.

That just masked the problem. It did not really solve the problem. That can only be accomplished by finding the voltage source and correcting the problem that is letting the voltage run on paths that it shouldn't be running on.

 

[K8MHZ]

That just masked the problem. It did not really solve the problem. That can only be accomplished by finding the voltage source and correcting the problem that is letting the voltage run on paths that it shouldn't be running on.

Some questions about that.

Was it not a code violation to have no bonding of the metal water pipes?

And what does it mean, 'letting voltage run?'

What I saw was a difference in potential between the floor drain and the shower head along with pipes not bonded. Bonding eliminated that difference.

What are you suggesting was (is) wrong and not corrected? A ground fault somewhere?

Was kwired's fix incorrect, too? Or just what I did?

Seriously. My sister still lives at the house we are talking about so I'm not looking for an arguement. If I missed something I will go there and check it out.

 

[renosteinke]

Bingo, K8. That electricity had to come from somewhere. You need to find that 'leak' and fix it.

 

[K8MHZ]

Bingo, K8. That electricity had to come from somewhere. You need to find that 'leak' and fix it.

A little more precision, please?

Let's start with what I measure at my house, a couple miles from hers.

The voltage difference between the metal pipe that is bonded to the neutral at my house and the earth is 2.6 to 2.8 volts no matter if the test electrode is three inches or three feet from the bonded pipe. This ground to neutral difference is a POCO thing and less than three volts is considered normal.

Now, let's say for arguement that before I bonded the pipe at my sister's house, the well pipe to drain pipe difference was 10 volts. Obviously, the drain pipe was grounded but not bonded. After the bonding of the well pipe, the difference went down to a volt or so.

So, now with the pipe properly bonded and the consumer complaint gone, what do I look for? If I disconnected all my metal water pipe from the neutral at my own home, where there never has been such a problem, what would the expected difference in voltage be? (I'm not going to do it, just wondering).

 

[don_resqcapt19]

Some questions about that.

Was it not a code violation to have no bonding of the metal water pipes?

The lack of a bond was a code violation.

And what does it mean, 'letting voltage run?'

That there is voltage where it does not belong

What I saw was a difference in potential between the floor drain and the shower head along with pipes not bonded. Bonding eliminated that difference.

Yes, I am sure that it did.

What are you suggesting was (is) wrong and not corrected? A ground fault somewhere?

I am suggesting that the voltage has to originate some where and that the correct fix is to find and eliminate that origination point.

Was kwired's fix incorrect, too? Or just what I did?

Just bonding is masking, not fixing the problem.

Seriously. My sister still lives at the house we are talking about so I'm not looking for an arguement. If I missed something I will go there and check it out.

It could be that you did. It is possible that the voltage was only the "normal" neutral to earth voltage and bonding is all that you can do. However the "normal" neutral to earth voltage is not high enough for a person to feel

 

[K8MHZ]

Don,

Thanks for the replies.

Before I did the bonding, there were three grounded metal systems at the house and none of them bonded.

The panel was grounded with one ground rod just under the panel.

The well water pipes ran above and were connected to the earth via the well, which is about 10 feet from the panel.

The drain water pipes are in dry sand until they leave the house, about 25-30 feet from the panel. From there they run away from the house, but toward the pole the transformer is on.

The transformer is on a pole with a ground rod, about 30 feet from the end of the sewer pipe.

So, over a distance of less than 100 feet in very wet (home is on a lake) soil, in nearly a straight line, we had:

Tranny electrode, sewer pipe, well, panel electrode. The only metal connection was from panel electrode to tranny electrode. The other systems were only electrically connected because they were in wet soil.

The connection to earth for the well and sewer systems were 20 feet or so apart, in line with the panel and tranny electrodes, but there exists only a few inches of difference between faucet and drain.

Several years ago, after I did the bonding, a storm came through and ripped out the neutral. The drop was replaced along with some other lines going to the house. So if the original problem was a bad neutral, there is a relatively new one there now.

I never saw, nor heard any complaints that would lead me to think there was a bad neutral, but there may have been. A small one may not have been noticed anywhere besides the shower.

 

[renosteinke]

As I said, get systematic, find out where the power is coming from.

Turn off the 'main.' Is there still voltage present? If so, the problem comes from somewhere else. If not, you have a fault somewhere.

Turn on your breakers one at a time. Find the one circuit that brings back the voltage. Your source is somewhere on that circuit.

Remove all appliances and turn off all switches on that circuit. If the voltage goes away, your problem is with one of the lights or appliances.

Test each appliance one at a time to learn which one is causing the voltage to come back.

 

[K8MHZ]

As I said, get systematic, find out where the power is coming from.

Turn off the 'main.' Is there still voltage present? If so, the problem comes from somewhere else. If not, you have a fault somewhere.

Turn on your breakers one at a time. Find the one circuit that brings back the voltage. Your source is somewhere on that circuit.

Remove all appliances and turn off all switches on that circuit. If the voltage goes away, your problem is with one of the lights or appliances.

Test each appliance one at a time to learn which one is causing the voltage to come back.

Are you suggesting that I disconnect the bond to the pipe?

That's the only way I will be able to check for the voltage that USED TO be present there.

 

[renosteinke]

Might have to, to see if the voltage is still present. Be a nice use for the Fluke with the reote display head!

Just for giggles.... amp-clamp the pipe. Can you measure a current draw?

 

[K8MHZ]

Might have to, to see if the voltage is still present. Be a nice use for the Fluke with the reote display head!

Just for giggles.... amp-clamp the pipe. Can you measure a current draw?

I posted a longer reply, and it evaporated....site maintanence or something.

I could clamp the bonding conductor, but I think the amount of current I am looking for will be less than my meter can see.

This amount would be what it would take to provide a tingly sensation while standing in water but nothing more severe than that.

 

[renosteinke]

It was just a thought .... that trailer with the 'live' skin - you definitly felt a shock - had no bond between the ground bus and the neutral bus - but it did nave a ground rod. When I asked about that, the maintenance guy told me he had removed the N/G bond because the 20A breaker kept tripping - suggesting that there was the possibility of some serious amps going through that metal.

Now, if only I had known that at the START of my troubleshooting ....

 

[j rae]

No ground

No ground

I once had a switch box ungrounded. The hot wire was shorted to the metal box and if in the shower and touched the screws that hold the swich cover plate you would get shocked.