My City's Code for Ground to Water Pipe

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This is a follow up to my previous post where the electrician ran a ground wire laying on the dirt outside the building before clamping to a water pipe faucet.
I called the city to find out the code on this. The guys said that the wire on the dirt was definitely not acceptable.
As to grounding a receptacle to a cold water pipe: the code allows it with no restriction whatsoever on location. I asked about the "first 5 feet" that some brought up, and he said that was not a requirement.
Anyway, I am of course going to undo that electrician's work and start over. I am having another electrician come over and take a look. He said he is open to doing it anyway I want (i.e. first 5 feet, add grounding rod also).
So I want to get opinions on what you think should be done. Remember, the object here is to ground 2 or 3 outlets--NOT to redo the entire electrical system.
I think what had been confusing me here is that I thought ALL houses had a grounding rod. Now, if I am correct, these houses (1960) were built with no grounding rods, and the water supply pipe (metal) IS the ground! So if that is true, then the grounded wire that they did run to the kitchen and bathrooms is grounded by the water pipe. Am I correct?
So, if that is true, if I just ground these to the water pipe it should be equal protection to what I have in the kithen, bath, and garage now. In that case, I am thinking what is the point in exceeding that for a computer or TV? (again, this is not meant to "upgrade" the entire electrical system or ground every plug).
So this gets to the issue of the ground rod. If it is just for these 3 outlets, I can't see it making sense. I'm sure you will have opinions on that :)
Now where to clamp to the water pipe. First, I am positive ALL the water pipe is metal. But I am open to suggestions on this. I can see the 5 foot thing making sense. But obviously will be more expensive. So should I request that (especially if there is no ground rod)???
Again, to be clear, my city does allow grounding to the water pipe in this situation.
So what do I do? I'm pretty open to the five foot thing, but the rest I am not sure if it is necessary in this situation.
-- John
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John Ross wrote:

Attaching an electrical system to a water pipe does not ground the electrical system - it grounds the pipes. Doing so is a safety issue for the plumbing, not the electrical system.
In my house, for instance, the piping in the house is metal. A metal pipe extends about two inches out of the side of the house where it connects to a plastic pipe for access to the municipal water system. The chances of any meaninful electrical "ground" by using water pipes is miniscule. The pipes in the house are, nevertheless, connected to the electrical ground elsewhere (by clamps).
So, then, you need an appropriate electrical ground consisting exclusively of a ground rod. You also need the piping in your house connected to that same electrical ground.
Bottom line: Drive a ground rod AND clamp on to a pipe (anywhere).
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HeyBub wrote:

The main water supply pipe (assuming it is metal) is a required part of the grounding electrode system -- and you are allowed to use it as a grounding point for the first 5 feet after it enters the house (that's a fairly recent restriction.) If he connected to it *outside* the house, that's the same as connecting directly to one of the existing ground rods. The only real issue I see is whether the wire is sufficiently protected from physical damage.
For adding an equipment ground to an existing ungrounded outlet (but not for new work) you are allowed to run a separate ground wire back to the panel or to any point on the grounding electrode system. It does not have to be run with the current-carrying conductors.
Bob
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zxcvbob wrote:

I don't understand what you mean by if it was connected outside it's the same as a ground rod?

Bob, just in case you mised it, here is what the new electrician is proposing.
1) Drive an 8 foot copper ground rod next to the water faucet bib.
2) Connect that to the water pipe.
3) Go in the crawlspace to this location (i.e. right where that pipe passes through wall) and attach clamp to water pipe.
4) Attach ground wire to that clamp and connect it to a box immediately above to be secured on floor joists (I am not sure but I think he said "junction" box).
5) From each receptacle that I want grounded, he will run a ground wire from that receptacle to the box he installed.
Does that sound appropriate?
-- John
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HeyBub wrote:

However, MY house is nothing like that.
The water supply enters the house through all metal pipe that is around 40 feet long to the street supply. So, since there was no plastic used back when this was built, I assume they considered that a better ground than an 8 foot rod.
Obviously no one else here seems to have such a set up. It was common in my city back in the '60s.
I'll report back what the new electrician says.
-- John
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John Ross wrote:

...
...
...
... It was common all over before the advent of plastic and NEC-compliant until (relatively) recently -- I think somebody else here mentioned the '87 Code revision which sounds about right.
Your city appears to have not yet required the later code and with the type of distribution system you have the water line ground will be perfectly adequate electrically (and, unless you were given bum information, compliant w/ the local code.) So, run your new ground(s) in a "workmanlike manner" and clamp to the existing system and you're good to go. Note, of course, that if the pipes have been painted for example you'll need to "shine 'em up" before making the connection.
--


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dpb wrote:

I think that would work, too, but funny enough the new electrician insists on a ground rod! Here's his proposal:
1) Drive an 8 foot copper ground rod next to the water faucet bib.
2) Connect that to the water pipe.
3) Go in the crawlspace to this location (i.e. right where that pipe passes through wall) and attach clamp to water pipe.
4) Attach ground wire to that clamp and connect it to a box immediately above to be secured on floor joists (I am not sure but I think he said "junction" box).
5) From each receptacle that I want grounded, he will run a ground wire from that receptacle to the box he installed.
Hopefully, nothing there opens a new can of worms!
-- John
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John Ross wrote: ...

...
What _should_ do is ensure your house has an adequate grounding system and if not, do what is a reasonable solution to make it so. Once that is done (or established that the present is adequate), the decision on how to add any additional ground connections should be pretty straightforward.
Any competent electrician should be able to answer the first question -- clearly, the one you had previously would likely fail that basic competency test.
As for conjecture, it is possible the house was built utilizing the city water system distribution as their ground. I think that would not meet today's NEC, but is possible it might still in some local jurisdiction that has their local code not refer to current NEC. It is probably adequate electrically but has some "issues" that are the basis for the current NEC requirements.
--
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wrote:

Your city must be on the 1987 national electric code. I guess they never heard of plastic parts (dielectric couplings etc) in the plumbing there.
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Ditto, either you didn't clarify what is being done, or the person you spoke to is clueless, or your city just doesn't follow NEC
If you look in your service panel, you'll probably find a ground conductor going to a driven ground somewhere

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There was a time in at least some areas when a metallic main water line was considered a better system ground than a driven rod. I have installed many such grounds. A driven rod was permitted only if there was not a metallic water main. As time went on and non-metallic pipe began to be used for the street and service lines, the codes changed to require both a driven rod for a system ground and a connection to ground any metallic plumbing to the system ground. So the metallic pipe in the house changed from being what you ground the electrical system to, since it was generally really well connected to the earth through the metal service and main line piping, to being something that you grounded to the electrical system because it might not be well connected to the earth because of the plastic. It's a little confusing but it all makes good sense when you understand the whole story.
Don Young
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wrote:

Back in the olden days when plumbing was one solid soldered copper system from the street to every faucet it was an excellent ground. Then the yuppies came. All it takes is one "whole house water filter" or water softener to turn that system into a floating antenna.
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RBM wrote:

These houses were done by a well known local developer from that era-- extremely well made tract houses. People are very aware of how they were built. So the inspector, knowing the time frame, knew exactly what I was talking about. Apparently, they don't follow the NEC. But remember, he was talking about retrofit, not new construction.
After the electrician comes, I'll post back as to the grounding rod. However, every indication is that there are none--they used the metal city water pipe for the ground.
-- John
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RBM wrote:

Here's the update:
My understanding is that the 5 foot rule applies to where the *panel* meets the water pipe and is part of my city's code. However, it appears that for a retrofit with a house that was grounded like this, that does not apply (only to new construction and changing the panel). So I guess they just grandfathered in the older code as far as I can tell. Anyway, here is what the new electrician proposed:
1) Drive an 8 foot copper ground rod next to the water faucet bib.
2) Connect that to the water pipe.
3) Go in the crawlspace to this location (i.e. right where that pipe passes through wall) and attach clamp to water pipe.
4) Attach ground wire to that clamp and connect it to a box immediately above to be secured on floor joists (I am not sure but I think he said "junction" box).
5) From each receptacle that I want grounded, he will run a ground wire from that receptacle to the box he installed.
Do you have any objections to any of that?
-- John
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John Ross wrote:

IIRC ground rods were required in 1960 only if the water service pipe was 'likely' to be replaced with plastic. More recently, replacing with plastic became more common and the code always requires a "supplemental" electrode (for new installations). Metal underground water pipe 10 ft or more length is *always* required to be part of the grounding electrode system.
Ground rods were the easiest supplemental electrode to install, but they are among the worst electrodes. If you have a single rod that is a code compliant resistance of 25 ohms to earth and connect it to 120V you get all of 5 amps. An extensive underground metal water supply system would likely have a resistance of about 5 ohms to earth - far better than a rod. For new construction the NEC generally requires a "concrete encased electrode" which is a good electrode and would be used as the supplemental electrode.

As long as you have metal underground water service adding a rod is not required for what you are doing.

The connection of the service grounding wire from the panel is now also required to be within 5 feet of the entrance of the water pipe to the house. IIRC in 1960 it could be anywhere on the water pipe, just like you used to be able to connect the added ground wires from outlets anywhere. The 5 foot restriction, as others have said, is because the solid metal of a water pipe may be interrupted.
If I was doing the receptacle grounding, I would try to split-bolt the added ground wires to the grounding electrode wire from the panel to the water pipe (or other electrode).
The electrical system is connected to earth, among other reasons, to keep the voltages at a reasonable voltage with respect to earth.
The major function of the receptacle ground wire is to provide a low resistance path so if the hot wire shorts to, for example, the metal case of a drill, there will be enough current to trip a breaker. The path is receptacle ground wire to service panel, through neutral-ground connection, back to the transformer on the neutral wire. The earth is essentially not involved in this function.
-- bud--
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bud-- wrote:

Well, the way he proposes to do it (see below) keeps intact the water pipe grounding system and the ground rod would be supplemental to that. So, if I understand it, if the ground rod was not as good as you say, the water pipe would make up for that (unlike most people here who I think are saying the opposite).

I have no idea what a "split bolt" is. :) This is how the electrician is proposing to do it:
1) Drive an 8 foot copper ground rod next to the water faucet bib.
2) Connect that to the water pipe.
3) Go in the crawlspace to this location (i.e. right where that pipe passes through wall) and attach clamp to water pipe.
4) Attach ground wire to that clamp and connect it to a box immediately above to be secured on floor joists (I am not sure but I think he said "junction" box).
5) From each receptacle that I want grounded, he will run a ground wire from that receptacle to the box he installed.

I didn't understand that last part about the earth not being involved. Could you dumb down your answer so I can understand it (as you can see, electric is not my strong point)?
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John Ross wrote:

<http://www.grainger.com/Grainger/wwg/productIndex.shtml?originalValue=split+bolt&L2=Split+Bolt&operator=prodIndexRefinementSearch&L1=Connectors%2C>
Proper connection of a ground rod is to the service panel neutral-ground system. The ground rod is to connect the *system* to earth. The rod is not allowed be used as the path for short circuit current to trip the breaker (as detailed below). The ground connection on the outlet *must* be returned by a metal path to the service panel 'ground'. If the metal water pipe path in your house became disconnected, the ground rod would not provide a safe path for current from the receptacle 'ground' terminal (as detailed below).

If this is allowed by your inspector, it is safe as long as there is a metal path back to the panel.

If I used a metal box, I would have all the ground wires enter through the same knockout. It is relatively minor, but with a single conductor through a knockout the steel box acts as a "choke". With all the conductors through the same knockout, the magnetic fields from current flowing in on one conductor are canceled by the current flowing out on another conductor. A decent explanation takes a lot more space, but the effect is relatively minor.

Basic plan sounds reasonable.

The second function of a 'ground' is providing a low resistance path that causes a high current for a hot-to-'ground' short circuit, and causes the breaker to trip. The path must be all metal to cause a high current. As I said, the path uses the service neutral as part of the metal return path to the supply transformer, and also uses the connection between the house 'ground' system and the service neutral that is required in all US services.
If the service was not connected to earth, the function above would still work the same - the metal path would be there.
You could try to use just the earth to provide the return path to trip the breaker if, for example, you connected the 'ground' terminal on a receptacle *only* to a ground rod. If you did that, in the example at the top with a 25 ohm resistance to earth, the current resulting from a hot-to-'ground' short would be less than 5 amps - which would not trip a breaker. The earth is not allowed to be used as the path for the short circuit current. In addition, because of the properties of the ground rod, the rod and receptacle 'ground' terminal would be at 120 volts with respect to the earth a short distance from the ground rod and other parts of the building 'ground' system.
-- bud--
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bud-- wrote:

The house was built with the water pipe (all metal) as the grounding system (i.e. there is no ground rod). I saw this ground rod he proposed as a "supplemental" caution. So it connects into the water system pipe which is grounded all the way out to street with galvanized steel pipe.
Now I am confused if this makes sense after all. But, the part you mentioned about not using the ground to trip the breaker seems to conflict with the often sited NEC code which says you can connect an ungrounded outlet to within 5 feet of the entrance point of the metal water supply to the house. The part about the neutral to panel--isn't that achieved through the current wiring?
My concern was if that junction box was allowed.
So bottom line, is it better to just to go directly to within 5 feet of water pipe entrance than this plan? Again, I thought the intention of that was if someone put a plastic pipe somewhere. So this added ground rod would simply be an insurance of having an *additional* part of the grounding system (i.e. not meant to become the new grounding rod).
But it seems now you are saying that is not the way it would work.
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John Ross wrote:

A lot of houses were built with just the water pipe to connect the electric service to earth (including all the housed I have lived in). They work fine unless the water service is replaced with plastic.

The code now requires a "supplemental" electrode for *new* construction in case the water service pipe is replaced with plastic. In the past the supplemental electrode has usually been a ground rod. The rod can connect at a number of places to the ground electrode system. The rod should have a relatively short connection to the panel. It is providing a path to earth from the panel. Connection near a water faucet is not appropriate unless the connection would have a short metal path to the electric panel. By code, if connected to the water pipe, the rod must connect in the first 5 feet of pipe inside the building. That may not be the best place to attach it. The code does not require adding a rod for what you are doing (your inspector might).

You can't use the *earth* as part of the path to trip the breaker. If the outlets are connected within 5 feet of the metal water supply entering the house there is a metal path for 'ground' current to trip the breaker (assuming the electric service is connected to the water pipe, which it should be). If the metal water pipe is maintained, connecting elsewhere on the water pipe gives you a metal path and you said that is permitted by your inspector (but is no longer allowed by the NEC).

A neutral-ground wire connection is part of a properly installed service installation. You should have it now - I did not question its existence.

A junction box can be used to splice the added ground wires.

For the receptacle 'ground' wire connection, I would connect to the grounding electrode system where it runs close to your outlets. That includes the heavy wire from the panel to the water pipe.

When adding a ground rod to a system with metal water service pipe, the rod is "supplemental". It becomes the only electrode if the water service pipe is replaced with plastic. But the ground rod is to connect the *system* to earth and should be a short path to the panel. I am reading that the intent was to make the rod "insurance" for the added receptacle ground wires in case the interior water pipe path was interrupted in the future. IMHO that is not appropriate.
--
bud--

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John Ross wrote:

UPDATE: The new electrician proposes to do the following:
1) Drive an 8 foot copper ground rod next to the water faucet bib.
2) Connect that to the water pipe.
3) Go in the crawlspace to this location (i.e. right where that pipe passes through wall) and attach clamp to water pipe.
4) Attach ground wire to that clamp and connect it to a box immediately above to be secured on floor joists (I am not sure but I think he said "junction" box).
5) From each receptacle that I want grounded, he will run a ground wire from that receptacle to the box he installed.
Does that sound appropriate?
He did see the other guys work and agreed with all of you it was wrong and against code. So I grilled him pretty hard about the above proposal and he insisted that it was up to code.
-- John
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