Galvanic Action?

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rattus

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Experts tell my neighbor that the ground wire on his cold water pipe has caused a leak under the slab foundation. Tell him to connect the ground elsewhere! House is 42 years old.

Anyone have similar experiences?
 
Is the pipe copper, lead, PVC, PEX???

Is the conductor AL or CU?

Is the clamp AL, CU or brass/bronze?
 
rattus said:
Experts tell my neighbor that the ground wire on his cold water pipe has caused a leak under the slab foundation. Tell him to connect the ground elsewhere!
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Is relocation of the connection supposed to repair the leak? :-?
 
celtic said:
Is the pipe copper, lead, PVC, PEX???

Is the conductor AL or CU?

Is the clamp AL, CU or brass/bronze?
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Copper pipe, and copper wire I think. Clamp is bronze I think. Will check it out.
 
rattus said:
Copper pipe, and copper wire I think. Clamp is bronze I think. Will check it out.
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If this is the case, I would say that the expert needs to provide more info as to how the copper conductor and brass fitting caused this leak. Remember that alternating current does not create pinhole leaks in copper pipes, DC current does.
 
Me Too:

Me Too:

Pierre C Belarge said:
If this is the case, I would say that the expert needs to provide more info as to how the copper conductor and brass fitting caused this leak. Remember that alternating current does not create pinhole leaks in copper pipes, DC current does.
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That is my opinion also.
 
Have the HO tell the water co. to install a dialectric break, and be done with it.

You must bond. If the water co. doesn't like it, they can instal the PVC break.
 
Pierre,
I would also appreciate a link to this theroy.
I have had this question posed to me before, and I did not have any solid information to pass along.
Rich.
 
Pierre C Belarge said:
If this is the case, I would say that the expert needs to provide more info as to how the copper conductor and brass fitting caused this leak. Remember that alternating current does not create pinhole leaks in copper pipes, DC current does.
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1./ Alternating current does have a small DC component during faults and even during switching.

2./ Two dissimilar metals placed in an electrically conductive substance will create a battery. This electrogalvanic action will cause electrons to flow from anode to cathode and will inturn cause material migration in the form of a chemical reaction - forming a salt - from the anode to the cathode. This effect is used in cathodic protection of underground metallic objects when large magnesium blocks - sacrificial anode - are welded with a copper cable to the metallic object. Couple of decades later when they think the electrode needs replacement they dig it up and most of it, if not all, is gone, so they just weld on another one.
 
What they really said:

What they really said:

Finally read the report and found that the leak was in a cast iron sewer pipe and unrelated to the ground wire.

They did however recommend removing the ground wire from the cold water pipe and grounding it in some other way, perhaps a ground rod. The rationale was that "incase of an open neutral, excess current would flow through the plumbing and cause problems".

I told the neighbor, "Don't do it!"
 
This is an exserpt from another article found here
http://www.wsscwater.com/copperpipe/copperpipewp.cfm

Stray Current Effects due to Electrical Grounding

The practice of using the water distribution piping as part of the grounding system for homes and buildings has been common place for more than 80 years [17]. It has long been assumed that alternating current (AC) has practically no effect on corrosion of the piping system. It is well known, however, that direct electrical current (DC) discharge from a metallic object can cause rapid and extensive corrosion. Documented cases of stray current corrosion have always been associated with DC.
A survey of public utilities was conducted [17] requesting case history information on experience with electrical grounding and water pipes. While many utilities acknowledged that grounding currents were thought to contribute in some instances to corrosion, the problem is essentially an external pipe corrosion problem. There is no clear indication from case histories or the literature that electrical grounding of the AC system through the water piping contributes to corrosion on the inside surface of the pipes. The water on the inside of pipes represents a far less conductive and favorable path for current discharge as compared to the soil or other metal objects in direct contact with the outside surface of the pipe. Corrosion, if it were to occur due to electrical grounding effects, should originate on the outside of the water pipe rather than the inside.
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