Water ground question

I'm not second-guessing my electrician, just gathering information for later.
We agreed to install 2 ground rods, per code, and then tie a second ground to the water supply line, also code I am told. With that they are also going to connect a ground between the hot and cold pipes at the water heater.
My question, what does the ground at the water supply do that the 2 ground rods don't? second question, as I intend on replacing all of my hot water lines with PEX, obviously the ground at the water heater will no longer exist - am I creating a dangerous condition or can I safely remove the metal hot water pipes and replace with PEX - so that I no longer have any metalic hot water pipes?
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On Fri, 22 Sep 2006 18:34:25 -0700, "Eigenvector"

If your supply into the house is plastic, not much. A metal underground water pipe is probably the best electrode you can get, particularly if the pipes under the street are metal.
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If you don't have a copper water line feeding the building , the two ground rods, ground the electrical system, and if you do have a copper water line it's bonded together with the ground rods to form a better ground. The interior metal water pipes are bonded to the electrical grounding system to prevent them from becoming electrically live, which they could do if isolated from the grounding system. If you replace the metal with pex, it can't become energized, so there is nothing to ground

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advise your electrician of your upcoming pipe changes so he connects to the metal cold pipe that supplies water near its entrance to your home. have him check your wiring to see if any previous homeowner handymen have used the water line for electrical grounding anywhere else inside your building, perhaps at the older washing machine for example. see Electrical Wiring FAQ for grounding info and more at: http://www.faqs.org/faqs/electrical-wiring/part1 /
Eigenvector wrote:

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They're aware that I will be replacing the pipes, however for the purposes of the inspection and code requirements they're still going to install the bonding.
I know they tied the kitchen outlets to the cold water pipes for one. I'll mention it to him when they come back to do the work. Today all they were doing was inspecting the box to make sure it would accept a ground connection and locate the utilities so that the ground rod wouldn't penetrate the gas main or break my crawlspace drains. They are going to tie the water line grounding to the cold water line just as it comes into the house - about 10 feet from the water meter.
Alright, so when I finally replace the hot water galvanized with PEX I simply remove the bonding and not worry about it.

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Ensures that no matter what might ever go wrong in the electrical system, the plumbing system will always be at electrical ground potential -- thus eliminating the possibility of an electric shock hazard from touching a pipe, faucet, etc.
--
Regards,
Doug Miller (alphageek at milmac dot com)
  Click to see the full signature.
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if some sectoions of metal pipe remain after pex intall those should be grounded at the service for safety.
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MAYBE.
At the limit, how far should one go in "grounding" every piece of metal someone might touch.
No question that a grounded sink is safer than a sink which is HOT because of some accident of repair or construction. (E.g.: a screw or nail cuts into a cable.)
But in electricity it takes TWO to tango and to kill you. If your sink is HOT you still need another ground to get a serious shock. A nearby grounded metal object is just a dangerous as the HOT sink!
Unless you live in the country you have a garbage disposal in your metal sink. The disposal will ground your sink.
If you don't have a disposal, I suggest that you don't go out of your way to ground your sink. Aside from everything else, there is no standard way of bonding a sink with plastic drain and supply lines to the local ground. Better that you have GFCI circuits to supply any non-grounded small appliances you handle in the bath or kitchen. Many heating appliances don't have a ground (toasters, coffee machines, irons).

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On Fri, 22 Sep 2006 18:34:25 -0700, "Eigenvector"

Guessing you live in a dry rocky soil area. Since code only requires one ground rod if a sufficient low ground resistance.

1. Meet the requirements of code, it is the first you connect to if the metal piping has 10 or more exposure to earth.
2. It bonds the pipe back to the panel, so if a hot wire comes in contact it creates a strong ground fault to allow for breaker tripping.
3. If the pipe is bonded to the panel, if you come in contact with any neutral and a metal pipe, there will be a zero potential for voltage and shock.

The water heater should be bonded ('grounded') via the electrial supply and from the bonded ('grounded') gas piping. The bonding jumper, from the hot to cold is to ensure 1. You maintain a bonding ('ground') back to the panel should your water heater becomes removed for work. Also, just incase your water heater isn't good for low impedance for ground fault current.
As for pex, you need to preplan all this. Talk to your building inspectors as well as your electrical inspectors. I remember a conversation with someone that pex wasn't allowed since it was believe water applicances(garbage disposal, instant hot water heater), might become engerized, and with no metal piping, a path for current would be lost, and the situation could remain deadly.
Remember, do work per codes and inspector recommendations, not by Newgroup posts. Be safe.
imho,
tom @ www.NoCostAds.com
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Tom The Great wrote:

<snip>
My town requires two rods on any new service or panel upgrade, 5' apart IIRC, and it is all farmland. Probably just some towns go code+.
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The NEC only requires one rod, but if you don't have equipment to determine the quality of the ground connection, you're required to drive a second rod six feet apart. For most of us, it just means you drive two rods
wrote:

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RBM wrote:

Hi, Checking the quality of ground? Use a light bulb. If light is full brightness = good ground.
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Tony, you're to practical for the NEC
wrote:

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wrote:

I never perform repairs per newsgroup, you all could be a bunch of paranoid schitzophrenics for all I know. However it does give me a good direction to look. I do appreciate it.
Actually my soil is glacial till, hard clay with tons of rocks, but 2 grounds is the code here. As for code and inspection requirements, in my city/county they are severe. The only thing I can do without a permit is paint, replace interior doors, and vacuum. And I deeply resent this fact as unnecessary, as time consuming, and costly.

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Eigenvector wrote:

You could move to the boonies where representatives of the "gv'ment" are routinely shot when they poke around. Or, if you like large cities, consider Houston.
We have no zoning in Houston.
When I recently replaced the breaker box, no permit was required. I just had to coordinate with the light company (private). They wanted 24 hours notice to break the seal. Said to call when we were done and they would re-seal the meter within two days after (it was up to us to actually unplug and re-plug the meter).
Somebody recently posted a link to the building regulations of some small town (I think in Nebraska) regarding -- you're not going to believe this -- municipal requirements for stairway bannisters. How wide, how far from the wall, how high from the risers, intimate detail on how to navigate corners and curves in the stairway, material requirements, combustibility, coefficient of friction, strength of attachement to the wall, on and on. Many pages. Dealing with just the bannister!
I didn't see any prohibition, however, on whether you could coat the bannister with lead-based paint....
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wrote:

Many places regulation is good, since it's percieved motive is safety, but the truth is it puts more home owner money in other people's pockets.
:)
Here is for crazy codes, I saw on some "this old house' show, pvc isn't allowed for waste pipes any homes in San Fran? You need to use copper?!!!!!
loving life,
tom @ www.FreelancingProjects.com
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Good lord that's a dumb one. Has to be someone on the city council that owns stock in a copper mine.

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wrote:

ground
It's usually easier and cheaper to put two rods in than to just put one in, measure the "resistance" and then MAYBE put in another rod.
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