Shocked from the plumbing pipe

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GilbeSpark

GilbeSpark

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A friend today told me about how he had a plumber doing something at his house and when he was in the crawl grabbed the water pipe and got a nasty jolt.

The house is all plumbed in copper and the water main into the house is copper all the way to the street. He recently upgraded from a 150A to a 400A service and he says he's sure the electrician didn't bond the plumbing pipes. I've got a few ideas about how the water pipe got current on it, but maybe you guys can shoot out some ideas I haven't thought of.

What are your thoughts on a method without just tearing apart everything in the house to find out where the voltage or current is coming from?
 
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First shut off the main and see if you still have voltage. This will determine if it is coming from your service. Once you determine it is either or not from your service then turn on the main and flip breakers off one at a time until the prob disapears. You know what to do from there. Ps also check neutral bond /ground at service.
 
Sounds like it could be a neutral issue. A visual of the overhead at your friends house, and/or the neighbors to determine if you see a neutral conductor damaged or disconnected from the weatherhead or the pole.

Put a clamp-on meter aroung the GEC going to the cold water from the service.
 
GilbeSpark said:
He recently upgraded from a 150A to a 400A service and he says he's sure the electrician didn't bond the plumbing pipes.
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Well, he surely should have! They might have a breaker tripping right now instead of having an energized pipe.
 
Hot water pipe or cold water pipe? And not a gas pipe I assume?

FYI there are sometimes "dielectric couplings" used on a hot water heater which could electrically isolate one run of pipe from another.

Then rubber grommets might be used on water meters which electrically isolate the street piping from the house.

And rubber/plastic grommets at sink fixtures/valves.

And of course short "replacement repair runs" of plastic pipe.
 
I am with Pierre here chaeck the service neutral. If that is not the problem then perforn other checks stated here.
 
I would be asking a lot of questions as to what exactly happened. In the absence of other symptoms on the building electrical system I would not expect there to be a voltage on the metal water piping. What else was he touching?
 
Went over there today to look things over. There's no cold water pipe bond and the hacks I mean professional "electricians" who did the service upgrade did a peach of a job on the service drop. No weather head, no mast, just a piece of SE split bolted (with rubber tape on the hots) to the triplex, coming curvedly down non-supported to the side of the house into the bottom of the meter can through a half-bent/knocked out concentric knockout hole with nothing protecting the SE.

He also replaced his AC unit and the guys left the old feed in place with the conductors dangling with the fork-terminal ends suck in the dirt and the other side still under the breaker. At least they left it in the off position, what a bunch of nice guys.

About the water pipe, there's no voltage on it just amperage. Depending on what's running in the house I got readings ranging from .9A to 8.4A.
 
GilbeSpark said:
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About the water pipe, there's no voltage on it just amperage. Depending on what's running in the house I got readings ranging from .9A to 8.4A.
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If there is amperage on it, it must be bonded. With a metal underground water piping system in a code compliant installation the water pipe is in parallel with the grounded conductor and there will be current on it. It is not uncommon to have 25% or more of the grounded conductor current on the water pipe.
 
25%? That seems like an awful lot. I've seen 5 amps pretty commonly but not much more than that. That just doesn't seem safe that anyone could go under the house and touch a water pipe with a knee in the dirt and get a good zap.
 
don_resqcapt19 said:
If there is amperage on it, it must be bonded. With a metal underground water piping system in a code compliant installation the water pipe is in parallel with the grounded conductor and there will be current on it. It is not uncommon to have 25% or more of the grounded conductor current on the water pipe.
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This is why I hear that plumbers/pipefitters do not like us using the water pipe as a GE. They would like to see this changed.
 
Well it so sad to read these things, in what fine county did this offense happen? (don't tell me it happens
every day across this country)
Surely, it sounds like a drive by job, including service drop, no inspection and no licensed installer.

Depending on their location are you sure that the Poco Service lateral
is large enough for their new service?

I know I've read a lot about working for friends here.
Why now are they bringing in you to fix it ? |: ) (let me duck)...
 
GilbeSpark said:
25%? That seems like an awful lot. I've seen 5 amps pretty commonly but not much more than that. That just doesn't seem safe that anyone could go under the house and touch a water pipe with a knee in the dirt and get a good zap.
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Just because there is current flowing on it doesn't make it a shock hazard. The only voltage to drive a shock is the voltage drop on the pipe and the parallel grounded conductor. This will normally be a voltage too low to feel. The same is true when you open the metal water pipe and get across the two ends assuming that the grounded conductor is in good repair. In this case again the only voltage between the two sections of pipe will be the voltage drop on the grounded conductor. If the neutral is open or has a high impedance connection there will be a hazardous voltage across the two open sections of pipe.
 
GilbeSpark said:
Went over there today to look things over. There's no cold water pipe bond and the hacks I mean professional "electricians" who did the service upgrade did a peach of a job on the service drop. No weather head, no mast, just a piece of SE split bolted (with rubber tape on the hots)

never seen a 400 amp service with a gooseneck before...could you take a picture? but i have seen 2 screw romex connectors used as split bolt connectors. never know what you will find from someone else.
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Could it be that the water service is plastic, then turns to copper in the house? If the copper is grounded in the middle of the run and your under the house on your back grounded. In LA you have to bring the bag to the main water service befor the enterence to the house. I drive a ground rod there and run it unbroken to the water pipe. The gas has to be bonded now also.

Terry
Power Tech
 
Power Tech said:
Could it be that the water service is plastic, then turns to copper in the house?
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The copper goes out of the crawl into the dirt, it does not transition from plastic to copper in the crawl space like most installs do around here that have plastic run out to the water meter. I'm taking the homeowner's word that it is copper all the way out, he said he had that part of the front yard dug up a couple of years ago because of a problem of a tree root going through his sewage pipe and he saw it when the plumbers were repairing.
 
This should be of a major concern if someone was to open up a metal water pipe.

I've seen it posted here OSHA requirements for plumbers to use and install a temp. re-bond of a water pipes if it becomes isolated.
I beleive the post was referencing servicing the water meter and using a temp bond. But the potentional doesn't stop at the meter!

Don, makes a very good point of this potional difference, don't get between it!
 
People get killed opening up current carrying water pipes. I no longer trust water pipes. I do what Pierre suggested and throw the clamp-on on them.
 
iaov said:
People get killed opening up current carrying water pipes. I no longer trust water pipes. I do what Pierre suggested and throw the clamp-on on them.
Click to expand...

But as Don said it is not just current, one also needs voltage present to make it dangerous. One also needs to take a voltage reading between the pipe and reference ground.
 
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