ECN Forum Forums Code Related Discussion NEC & other Code issues Bonding of water piping.

Yes Winnie, you are correct. I meant electrolyte.

You are better with batteries than me. I have a clearer picture of them already now just from reading your last post.

Assuming it's electrochemical, how does the current path include metal outside the immediate area? There would need to be another electrode involved. Sort of a bipolar battery. Shunting one half essencially removes the common electrode from the circuit. ?

Edit: I don't see the AC effecting the elctrochemical reaction. If it reduces the effect on one side of the rail then it would increase the effect to the same degree on the other side.

[This message has been edited by Physis (edited 01-19-2005).]

They have done some studies around here pursuant to lawsuits against copper manufacturers and water companies. The contention was that most of the corrosion pin holing was caused by current being introduced into the piping by bad grounding/bonding, not that it was actually coming from the metal chemistry in the pipe.
I don't know if it was ever really resolved.

I suppose that is what Harold was addressing with his jumpers.

In my world, you can bet if there's a lawyer involved, everything that can be done to remove the truth has been done.

You, saddly, can rarely find truth in a court room.

I'll stick to science, physics and text books.

So, a legal entity tells a plumber he "must" use copper pipes or he might end up in jail. The plumber goes to the hardware store to buy some copper pipes. The hardware store puts in an order with the guy who makes copper pipes.

So now some lawyer, with the help of some court (possibly from the same jurisdiction that ordered the plumber to use copper pipes) decides the guy that makes copper pipes has caused harm to nearly everybody.

Nobody will point to the authority who "ordered" the plumber to use copper pipes. And study what? Just because I can't readily answer the question, this whole subject has been well understood for at least 50 years if not more than a hundred.

Lawyers.

Edit: The guy just makes copper pipes.

Edit: I was a little sharp with Harold initially, I should appologize for that.

[This message has been edited by Physis (edited 01-19-2005).]

They were pointing to that middle school science project where you put 2 dissimilar metals in water, applied a current and made oxygen and hydrogen, eating away some of the metal. True or not, I don't know but it did get the <government> water company off the hook. I think they were still going after the plumbers and pipe company, contending that the pipe should have held up better. I guess the only thing more attractive than deep pockets is a pocket that is not protected with unlimited government lawyer money. I have plastic pipe and didn't have a dog in the fight so I wasn't paying much attention. I tried to google it and all I got was a bunch of articles from plastic pipe companies trashing copper.
It was in Cape Coral Fl

I think it was Volta that discovered that reaction.

Edit: "didn't have a dog in the fight"

Edit: imagine that, the government interest vindicated.



[This message has been edited by Physis (edited 01-19-2005).]

Physis,

All chemical reactions involve electrons moving around. In an electrochemical cell, you have two separates types of reactions, physically separated, one happening at one electrode, the other happening at the other electrode. One reaction uses up some of the available reagents, and releases some electrons. The other reaction uses up some of the available reagents and absorbs some electrons.

As an intermediate between these two reactions, some ionized material has to physically move between the electrodes.

When current is flowing, the reagents are being steadily used up. A flow of electrons goes from one electrode to the other via some external circuit, and a flow of ions goes though the electrolyte.

There is no requirement that the electrodes be in the immediate vicinity of each other, nor does the external circuit need to be small. The electrochemical cell has lower resistance if the electrodes have large surface area and are close together, but the cell will work even with high resistance. If you stick dissimilar metals into a lemon, separated by inches, you will have sufficient power available to run a clock

-Jon

Ok, but this is going to have to be some pretty poluted water for one union to take out a bunch of pipe.