grounding electric box to copper water pipes

[Steve Bakken]

Our house was built in the 1950's and lately we've been getting pinhole leaks in the copper water pipes in the basement. Our plumber who fixed them said that it was from the electrolysis caused by the fusebox being grounded to the water pipes. Makes sense. Suggested that we have an electrician take care of it to prevent it from getting worse. Had the electrician out and explained the problem, so he ran new ground cable along the water pipes, clamping it to the pipes every six feet or so from the fuse box about thirty feet to where the pipe comes out of the floor slab. Now I may not be understanding something, but didn't that just make the problem worse? Now it's REALLY grounding on the pipes. Or was the problem that it wasn't grounded well enough before? I'm confused.

[LightningBG]

Hmm. Few things to consider...

Could be galvanic corrosion. Galvanic corrosion is caused by self-induced current created by electrical potential of two dissimilar metals in contact with an electrolyte. It can occur when two dissimilar metals (such as copper tube and steel pipe) are connected in the presence of an electrolyte.

But, assuming it was due to a bad ground...

(cut from another source)

Many times a house's electrical ground wire runs along next to the cold water pipe. A braided cable is usually found running along next to the water pipe, then your house's electrical ground becomes the water supply entering the house. This braided cable should connect around the water meter and reconnect at the pipe inlet to the house. Your situation may be that this braided cable is missing or has an open circuit or it is corroded somewhere along its length. To correct this a new braided cable should be run from the water inlet to the house all the way along the pipe until the electrical meter. Leave this exercise to an electrician to make sure this is indeed your situation.

If this doesn't do the trick, I'd get a dedicated ground installed (instead of piggy backing the water lines)

[DANR]

Years ago I had a camper with copper plumbing. Went through 2 water heaters before someone told me that was the problem. I strung ground wire and never had another problem

[Steve Bakken]

did you string the ground wire along the tubing then? It seems to me that any sort of connection between the electrical system and the plumbing system would compound any electrolosys problem

[CAMAN]

A couple things to check is to make sure you have a copper jumper across the water meter, if it is not there DO NOT touch it call an electrician, but hopefully the one you had made sure it was there. Another thing to check is the sacrificial anode in your water heater, it may be completely gone and now your plumbing is being eaten. Anodes should be inspected every couple years, and if your water heater is 10+ years old and never been inspected there is a good chance it is completely gone.

Another good idea is to get a grounding rod installed, its a heck of a lot cheaper to do than replacing your entire plumbing system or having a flood on your hands.

[krinkle]

You might just want to look at getting your copper water pipes replaced. 60 years is a pretty good run on copper want piping. I would bet you dont have many other things around that are 60 years old and still survive daily use. There are parts of the twin cities that copper water pipe doesn't last much more than 5 to 10 years.

There is more than just electrical current running threw the pipes that can eat away at it. Water pressure, speed of the water, minerals or other stuff in the water, temp of the water, and so on can all play a part in deterioration of the pipe. It seem to me that if the inside of the copper piping does not form a build up on it then the water is free to eat away at the copper. Water will eventually eat threw any thing.

If you have had just one pin hole in the piping maybe its just dumb luck. If you have had a few spots leak look at replacing the system. Many times when we cut out these pin hole copper leaks if you look inside the pipe you can see long areas where the water has eaten away the copper. Even if it was the electrical ground that caused the problem the damage may all ready be done.

I have not seen any newer water piping systems where they use pex or cpvc have these issues with water eating threw the sides of the pipes. Just make sure who ever puts in the new system does a quality job and you should be good to go for another 60 years or more.

[Whoaru99]

Had a similar-sounding situation at my GF's house. Seemed like every month or two I was patching in a new piece of copper pipe due to pinholes.

There was bad/loose connection on the water pipe bond and (as best I can recall) no jumper across the meter. I fixed the connection and added a jumper across the meter and haven't since had to patch-in any pipe.

Coincidence or problem solved? Not sure, but it's been almost a year since the last pipe repair.

Also, if there is not a ground rod system I think I'd look into that as well. If the root cause is the pipe grounding, providing a better path should help with the pipes. The system all has to be bonded together so not talking about removing the bond from the pipes, but adding code-approved grounding rod(s) in addition to the pipes, if not present.

[JohnMickish]

I am guessing it's a combination of old pipes and corrosion caused by someone using the wrong clamp. When clampint to copper you MUST use a copper clamp and not a steel or galvanized one. Your electric service MUST be grounded to the water pipe within 6 feet of where it enters the building, and the water meter MUST be jumpered around.

[DANR]

Steve

I should have given more details. It was a 120v/12v system. They used the copper plumbing as the negative wire for the DC The electrolysis ate the water heater full of holes twice. Once the two were isolated, problem solved. Not the same situation that you have, but the point is if you have electolysis metal will waste away.

[Steve Bakken]

so if i replace it all with plastic piping, I will still need to ground it to the water pipe where it comes into the house, correct? I assume this is code? What about running a seperate ground rod. Am I still required to ground it to the pipe as well?

[Whoaru99]

I believe any metal water pipe in the house has to be bonded to the house grounding system.

Also I believe all parts of the grounding system have to be bonded together so while there are separate bits to it, there really isn't anything separate about it because it's all bonded/connected together.

Before you go replumbing the whole place I think you've got a few relatively simple things to try...

Check for jumper around water meter (if you have a meter).

Check anode in water heater.

If there is no grounding rod system then have that installed by electrician.

[JohnMickish]

If you have water coming into the building with metal pipe, you MUST ground to the water pipe. You can still put in another ground rod, but if there is water you have to go there.

[Steve Bakken]

Ya this is the sixth time we've had to deal with this so it's time to just get it all out of there. I think i'm gonna switch to plastic though

[krinkle]

Its hard to go wrong with new. Have seen plenty of people that spend a lot of money on repairs and in the end have the entire system pulled out including the expensive repair areas.

I think many of the plastic piping systems on the market today will far outlast copper.