Remove the cold water ground?

[GG]

Hello fellow sparkys. I was on a bid today where the plumber was already there and He was giving the customer a bid for some plumbing pipe that he said needed to be replaced. He was the first plumber/salesman I have seen in a suit and tie. :roll: Anyway he informed me that the customers plumbing pipe had major "Electrolysis" damage from current traveling on the plumbing pipe and that I was to remove the CW ground and NOT reconnect it. That didn't sound like a solution to the problem so I asked him what would happen if I clamped my meter around the water pipe, shouldn't I read amperage flowing on the pipe causing the electrolysis? He said you you?sure will. Well needless to say I didn't get any amperage at all and no voltage at all with my meter on the water pipe. So what gives? Is this some new sales pitch they give the homeowner so they can replace a bunch of water pipe that has just corroded due to age? Is there such a thing as electrolysis? Should I listen to him and not reconnect the cold water ground?

 

[petersonra]

Re: Remove the cold water ground?

the code requires a connection to all grounding electrodes available. if the incoming cold water pipe meets the requirements of a GE, it nees a green wire on it.

this is the kind of thing that needs to be reported to the local AHJ so they can deal harshly with someone who ought to know better.

 

[inspector 102]

Re: Remove the cold water ground?

It is my understanding that the electralysis can be caused from numerous items, both internal and external to the pipe. The GEC is required by the code and needs to remain connected. I have been told that electralysis can be created due to excess solder in the pipe at elbows creating air turbulance. I have seen where the copper is completely pitted on the inside due to some type of reaction. I would not allow the GEC to be removed.

 

[electricmanscott]

Re: Remove the cold water ground?

Originally posted by petersonra:
if the incoming cold water pipe meets the requirements of a GE, it nees a green wire on it.

Sure per code you have to connect to this but it does not have to be green.

 

[macmikeman]

Re: Remove the cold water ground?

They also make good copper pipe and they make lousy copper pipe. This house might have gotten lousy copper pipe.

 

[physis]

Re: Remove the cold water ground?

I've gotten into a couple discussions about electrolysis and grounding electrodes. It can get a little involved and I forget some of the things that come up. But there is one point that's important. Electrolysis is something that usually happens in a DC environment. Not to say it doesn't happen but the bond to the service neutral probably has nothing to do with any electrolysis.

If you want to find current associated with electrolysis you'll want to set your meter for DC.

And give the plumber what for for suggesting an illegal remedy to a potentially nonexistant problem. I'll bet he didn't offer any evidence to support his hypothesis.

Edit: I left out half a word.

[ June 28, 2005, 02:13 AM: Message edited by: physis ]

 

[pierre]

Re: Remove the cold water ground?

We have not seen this action from plumbers here, but the Water Company has been trying this.
Because pipes have been turning green and they blame it on the electricl system.

 

[don_resqcapt19]

Re: Remove the cold water ground?

Sam,
While I agree in general that the gounding connection does not normally cause damage to the water pipes, there is some reason to believe that it can. Metal oxides can act as a diode and in some cases the oxide at the connection to the water pipe will become a rectifier and DC current can cause electrolysis damage to the water piping system. The damage would have to occur where their is current flow between different conductors like joints in the pipe or connections to other types of pipe.
I think that the use of the metal underground water pipe is a danger to the plumbers who repair the underground lines and if I was the water utility I would install a dielectric fitting just outside of the water pipes entrance to the building to remove this safety problem.
Don

 

[straps]

Re: Remove the cold water ground?

Don:
Sorry old friend but you are dead wrong. What has to be done is you are supposed to put a jumper wire with 2 pipe grounding clamps around the area of repair and then cut the pipe and after all repairs are done then remove the temporary by-pass ground the telephone co has been doing it this way since the beginning of time . Why cause their bsps say to do it that wy also the metal sheathing on the cable requires it as that is the safety ground on the Bell System.
Ex Cable Splicer who got smart and became a sparky a long time ago.

In NYC 90 percent of the grounds are done via the galvanized plumbing system thruout the city thats why pvc is outlawed in nyc and mc cable / bx is manditory in all structures inside the 5 counties the only alternative accepted is of course emt inside and threaded aluminium outside emt outside the structure in nyc is a automatic red tag.On the job.
Dont let the plumbers bulldoze you They have won the fight in South Florida where its manditory for 2 ground rods on all services with a pice of 1 1/2' pvc put over the end of the ground rods.If you go back in 2 years and grab the ground rods they snap off from the high concentrations of minerals in the soil ( Very acidic soil 8 feel down to I cant dig that far) The Orientals keep popping out of the hole ( I guess I got to China)

 

[physis]

Re: Remove the cold water ground?

It is true that copper oxide and copper make a diode Don.

I don't know how often it causes a problem, it's possible.

 

[hurk27]

Re: Remove the cold water ground?

electrolysis damage can happen with AC or DC current, We had a apartment building with a loss primary neutral that caused the exposed concentric neutral to first dissolve then the water pipe started getting leaks so plumbers replaced it with plastic then the rod electrodes finely dissolved enough that there was 56 volts on all the grounding in and around the building including the POCO's pad mounted transformer. We were finely called when basement floor tenets were getting shocks off the shower handles while standing on tile over concrete floors, I say all of this to say one point, Find the cause of the current!!!

If the last of the ground rods were to completely dissolve there could have been the full primary voltage (7200v in this case) placed upon all the grounding and everything connected to it. So think about this when disconnecting a EGC with current on it, It might be your last!

 

[physis]

Re: Remove the cold water ground?

If you're gonna energize the ground you probably will have some electolysis.

 

[steve66]

Re: Remove the cold water ground?

There must be something we can blame on the plumbers. Stray voltage, arc faults, dimming lights when the HVAC kicks on, or even global warming.


Steve