Water Main..yes or no?

[ICE]

The situation is thus:

Service panel upgrade 200amp. There is a ufer directly below the panel.

The water main is metal and on the other side of the dwelling. The contractor wants to attach a #4 GEC to a hose bib near the panel and not go to the water main at the other side of the dwelling. The dwelling has copper water pipe.

An electrical engineer is trying to convince me that this is okay. He has agreed to give weight to the opinions that I find here at the forum...so please do tell me what you think.

 

[jar546]

The situation is thus:

Service panel upgrade 200amp. There is a ufer directly below the panel.

The water main is metal and on the other side of the dwelling. The contractor wants to attach a #4 GEC to a hose bib near the panel and not go to the water main at the other side of the dwelling. The dwelling has copper water pipe.

An electrical engineer is trying to convince me that this is okay. He has agreed to give weight to the opinions that I find here at the forum...so please do tell me what you think.

Throw in 2 rods below the panel along with hitting the copper water bib and you have yourself a deal.

 

[ICE]

Throw in 2 rods below the panel along with hitting the copper water bib and you have yourself a deal.

So the requirement for landing on the water pipe within five feet of where it enters the building is not an issue?

 

[Beniah Naylor]

If you can use the Ufer as your grounding electrode, then bond the water pipe to your grounding system at any convenient location in accordance with 2017 NEC 250.104

If you are using the water pipe as a grounding electrode, then the 5' inside the building rule would apply. You would also have to bond the Ufer and the water pipe together per 250.50, to create a grounding electrode system.

Unless the Ufer is not viable for some reason, I would definitely allow them to bond the water pipe from the hose bib per 250.104.

 

[ICE]

Well so far the consensus is that if there is a ufer or rods present, the water main is not required to be utilized as an electrode. But the water main is serving as an electrode and the water pipe from the hose bib to the main is serving as a grounding electrode conductor.

I must say that according to these opinions, I have been getting it wrong for a long time. Given that a bonding jumper for a water pipe shall be sized per Table 250.122, the largest circuit in a panel that could potentially energize a water pipe would be the determining factor. The jumper could be anywhere from a #14awg to a #6awg.

 

[Beniah Naylor]

To go one step farther:

Assuming that the water pipe/main is a grounding electrode.

But the Ufer is a viable electrode by itself, and you are using it as your primary grounding electrode for this house.

Then the water pipe is an "auxiliary electrode" per 250.54, and is therefore not required to comply with requirements of 250.50, 250.53(C) or 250.53(A)(2).

The requirements of 250.50, 250.53(C) or 250.53(A)(2) reference other sections of the code, and when you untangle that complicated web, you realize that the NEC does not care how or even if you bond an "auxiliary electrode", because an auxiliary electrode is (A) not required in the first place, and (B) it isn't an auxiliary electrode if it isn't bonded to your grounding system.

So, the only section relevant to this scenario would be the requirement to bond your water pipes per 250.104 (A), the bonding jumper for which is sized from table 250.102(C)(1), which for a 200 amp service would be #8 through #4awg copper conductor, depending on how you read the table. All of this is from the 2017 code, so may have changed in the 2020.

 

[ICE]

I haven't heard of the term "primary electrode".

250.50 states that all of the electrodes as described in 250.52(A)(1) through (A)(7) that are present at each building shall be bonded together to form the grounding electrode system.

250.52(A)(1) is metal underground water pipe.

That means that the metal water pipe shall be an electrode.

250.53 (D)(3) Requires a supplemental electrode for an underground water pipe electrode. That can be any of the electrodes specified in 250.52(A)(2) through (A)(8)

250.68(C)(1) states that a connection to an underground water pipe electrode shall be within five feet of where the pipe enters the building. It further states that water pipe located more than five feet from the point of entrance shall not be used as a conductor to interconnect electrodes of the grounding electrode system.

 

[Joe.B]

ICE, I believe your analysis is correct. All available electrodes shall be used, in your case the metal water line (assuming it meets the conditions of 250.52(A)(1) as you stated) and the Ufer ground. If the water line didn't qualify as an electrode then they would be correct for bonding purposes. Adding two ground rods would not change this in any way, it would be wasteful, unnecessary, and could pose hazards.

 

[Joe.B]

Also, if you haven't already check out Mike Holt's forum, it's primarily electricians and the moderators strictly close any DIY threads so the information is very professional and stays on point. They have chewed this topic up many times and I believe you would find your analysis holds up there as well.

 

[Mark K]

The electrical engineer understands how the system will act electrically and what is necessary to provide a safe system. Building inspectors are technicians familiar with the regulations but lacking in an understanding of the electronics.. In such a situation I would defer to the opinion of the electrical engineer. If you do not feel this is appropriate I would suggest that the building department consult with its own electrical engineer.

If you were in a hospital how would you feel if the nurses could override the judgement of a doctor.

I believe using copper pipe instead of a #4 wire will provide a better connection and hence less resistance. So you want to make the system less safe.

 

[Beniah Naylor]

I haven't heard of the term "primary electrode".

250.50 states that all of the electrodes as described in 250.52(A)(1) through (A)(7) that are present at each building shall be bonded together to form the grounding electrode system.

250.52(A)(1) is metal underground water pipe.

That means that the metal water pipe shall be an electrode.

250.53 (D)(3) Requires a supplemental electrode for an underground water pipe electrode. That can be any of the electrodes specified in 250.52(A)(2) through (A)(8)

250.68(C)(1) states that a connection to an underground water pipe electrode shall be within five feet of where the pipe enters the building. It further states that water pipe located more than five feet from the point of entrance shall not be used as a conductor to interconnect electrodes of the grounding electrode system.

You are correct that there is no definition of "primary electrode" in the code.

However, in my opinion, if the Ufer can stand alone as the grounding electrode for the house, then any other electrode would be an "auxiliary electrode" per 250.54. I would agree with you that the water pipe is an electrode, but since the Ufer could stand on it's own, the water pipe is "auxiliary".

250.54 specifically says that 250.50 and the supplemental requirements from 250.53 do not apply.

250.68 is about the connection of a GEC at the service, which, in my interpretation, means that if you were using the water pipe as your grounding electrode for your service, you would have to comply with 250.68.

However, if the water piping system is only an "auxiliary electrode", since you are using the Ufer, then 250.68 would not apply, because it only refers to the the GEC connection from the service to the grounding electrode. 250.68 would apply to your connection to the Ufer, but not to the connection of the water pipe.

So, the question is, is that water pipe an "auxiliary electrode" or a non-auxiliary electrode? If it is a non-auxiliary electrode, you are entirely correct. If it is an auxiliary electrode, then it only has to be bonded per 250.104 (A).

My only input on that is, what is an auxiliary electrode, if it isn't an electrode that is not required to be there for the system to be grounded?

 

[Joe.B]

I understand the logic and personally I agree. The CEE is the electrode. Same house with a plastic main, only use the CEE and it's good. It is not what the code says though. Inspectors enforce code and are responsible for making sure jobs are compliant. If we listened to every engineer or architect our heads would spin. If every inspector just followed what they thought was right or wrong then what's the point? There is a process in code for alternate methods and materials. If the electrical engineer feels strongly about not following code then they submit their alternate design to the building official for approval. R104.11

The question posed was about interpreting the code and I believe ICE has the proper interpretation. It's not a question of understanding the science of grounding and bonding, it's about what the code says.

 

[Beniah Naylor]

So, as an example to illustrate my point, say you have a perfectly compliant electrical system for a house with copper piping, grounded with a Ufer. However, the point where the copper pipes attach to the main is insulated, say with a section of PEX or CPVC. The copper piping is bonded in accordance with 250.104 (A), which does not require the bonding connection to be located within 5 feet of the point of entrance to the building. All of this is compliant.

Now, you add another electrode, a ground rod (for example). The new electrode is an "auxiliary electrode" per 250.54. Every definition of "auxiliary electrode" that I can find indicates that an "auxiliary electrode" is an electrode that is present, but not required by the NEC.

This new ground rod is exempt from the 250.50 requirement that requires all the electrodes to be bonded together, and it is exempted from meeting resistance requirements that would trigger the need for supplemental electrodes.

250.54 exempts the auxiliary electrode from basically any requirement you could have. So let's go a step further - a metal underground water pipe is an electrode permitted for grounding per 250.52, just like the ground rod.

It isn't required to be present, but you decided to add a metal underground water pipe to your system instead of the ground rod mentioned previously, because you decided it was a better choice. This new metal water pipe is not required for the system to be grounded, and is not required per the NEC. You just added it because you wanted to.

The new metal water pipe would be an "auxiliary electrode", and is not required to comply with 250.50 at all. Because it is a metal water pipe, it must be bonded per 250.104(A), which does not reference 250.68 - that is a section that does not apply to the requirements of 250.104(A). The water pipe can be bonded from any point, as long as it is accessible per 250.104(A).

250.68 says that pipe located more than 5 ft from the entrance of the building shall not be used to connect the electrodes of the grounding electrode system, not regular bonding of the water pipe per 250.104(A).

250.54 says that you don't have to connect the auxiliary electrode to the other electrodes.

So, I would say that in the instance the OP describes, the bond at the hose bib will comply with 250.104(A), and the requirements of 250.50 and 250.68 are nullified by 250.54.

However, I do think what ICE wanted them to do originally is a marginally safer installation. I just don't think that you can say that it is required per code unless you can prove that the water pipe is not an auxiliary electrode.

Sometimes these issues are very difficult to call, which is why we have AHJ's... I could effectively debate this one in either direction.

 

[Joe.B]

Your logic is sound and I agree with you in principal, but that is not how the code reads in my opinion. 250.50 "ALL grounding electrodes as described...that are present at each building or structure served shall be bonded together to form the grounding electrode system." 250.52 (A)(1) metal underground water pipe, if it meets those conditions it must be bonded together as part of the GES per 250.68 (C)(1) which clearly says "Interior metal water piping located more than 5 ft from the point of entrance to the building shall not be used as a conductor to interconnect electrodes of the grounding electrode system." What you're proposing is technically not compliant and to be approved properly it would need to be submitted as an alternate method per R104.11. It's probably easier just to run the connection to the proper, code compliant point.

 

[ADAguy]

Also, if you haven't already check out Mike Holt's forum, it's primarily electricians and the moderators strictly close any DIY threads so the information is very professional and stays on point. They have chewed this topic up many times and I believe you would find your analysis holds up there as well.

Mike "H" has been the "source" for decades and has great illustrations.

 

[ICE]

Make "H" has been the "source" for decades and has great illustrations.

I went there and have not gotten any answers to the question. So far here I have Jeff, Beniah Naylor and an architect on the side of using the hose bib for a point to connect a GEC/bonding jumper and perhaps it's all a waste of material. Then there's Joe.B. One person out of all the people that see this here and at Holt's forum has understood and replied. Now that engineer and his contractor are going to chew me out. Oh well, I've been chewed out before.

I won't repeat this mistake....I'll ask the mailman next time

 

[north star]

@ ~ @ ~ @

** Tiger **, ...FWIW & IMO, I believe that you are interpreting the
electrical code correctly about using the existing, metal water
piping as a "required" point of grounding [ i.e. - shall be used ].
I believe that you have presented your case for using the water
pipe in Post # 7, ...legally, methodically & correctly !........So what
if the Contractor and engineer disagree with your interpretation.
You have been doing this for years \ decades..........H_ll's Bells,
Shirley you are not going to get your feathers ruffled over this
one application.

You have presented your interpretation of the legally adopted
Codes, ...they have theirs !.........This the way the current system
operates.

The main thing here is that the structure has a safe grounding
system that actually works and provides a level of safety to the
occupants.

I suppose you could retire from what you are currently doing
and become a Contractor or engineer, and start applying your
skills and "life knowledge" to the built environment.......You
may or may not have any more success though !.........From
looking at all of your posts over the last few years, lord knows
that an improvement in the area of residential electrical
systems is GREATLY needed !.........Besides, you are not going
to let them contractors \ engineers \ city managers get the best
of a fighting tiger, are you Shirley ?

I GREATLY encourage you to stay in the fight sir !

P.S. If you ask the Mailman next time, ...he \ she is going to say
you should have used the mailbox as a grounding electrode.

@ ~ @ ~ @

 

[ICE]

As long as I’m in the dispute, I’m in it to prevail. I was counting on the forum to shut down the argument that I was getting from the engineer. It had not occured to me that one can simply label a metal underground water main as an auxiliary electrode and then ignore it. My take on an auxiliary electrode is that it could be added but not subtracted. By that I mean that if an electrode as listed in 250.52 exists when a service is being installed it shall be bonded to the grounding electrode system. Simply because there is a functioning electrode of one sort does not give leave to ignore the other suitable electrodes by labeling them auxiliary electrodes.

Beyond that is the fact that by attaching a bonding jumper to a hose bib that is part of a metal water pipe system that has =>10' of underground metal water pipe, a dangerous condition has been created. An explanation of lightning is warranted here but suffice it to say it presents a real hazard. For a better understanding use Google. But wait, there's more.

I will end my participation in the beating of this dead horse with a tale.

Some years ago I received a call from a person that had to do with a tingling sensation when they were in the shower. They were experiencing a small electric shock. I advised them to not touch any pipe and to hire an electrician to find the source of the shock. The explanation that I was given is that a neighbors defective electric service was utilizing the neighborhood water pipes as a neutral return path. I was not a witness and people make stuff up but it seemed plausible. Now I am not sure that this is a reason that the code disallows the use of water pipe as a GEC and I am convinced that the door is not open to labeling an existing metal water main as an auxiliary electrode and doing whatever.

 

[steveray]

I'm in the connect within 5' camp....

250.50 "ALL grounding electrodes as described..

That is the difference between the grounding electrode and bonding of metallic piping as I see it...

 

[ADAguy]

And what of high or varying water tables to this issue?

 

[Mark K]

When two or more wires are connected, whether it is called bonding or grounding, the current will flow from high voltage to the lower voltage. The electrons do not differentiate.

You want a good ground to to assure you know the direction of the electron flow but also to maximize the current when a short occurs thus allowing the fuses/ circuit breakers to operate. You want a common ground in your building.

If your building has a good ground near the service entry you do not need water pipes for a ground. The only electrical justification for connecting the water pipes to the ground is in case somebody inadvertently applied a voltage to the water pipes. If this is the case it really doesn't matter where you connect the water pipes to the ground since they are a good conductor.

If your water pipes act as a ground this means that current will flow through the pipes and this current will over time cause corrosion in the utilities piping. It would not surprise me if the water company were to electrically isolate the utility mains and the service to the house much like they do with gas piping. If this is the case then the water pipes cannot act as a ground.

Remember the electrons have not read the electrical code and they are not limited by any interpretation of it by an inspector.

 

[Mark K]

Water table will impact the resistance of the ground but if you have a good ground this is not something you should worry about.

 

[ICE]

And what of high or varying water tables to this issue?

That has not been a consideration that I am aware of but moisture does play a role.

Many years ago I was an employee of a firm that manufactured high vacuum deposition machines. The machine created a vacuum equal to outer space and then directed an electron beam at an ingot of gold. The ingot would vaporize and coat silicone wafers. The wafers were the platform for computer chips. National Semiconductor Corp had a bunch of the machines. My job there was as an assembler... I wired the machines and the power pack that supplied 100K volts to generate the electron beam.

Well NSC had an issue where they would lose control of the beam. Not a good thing as the unit could explode....an one did...in our factory. That explosion killed three people and as a result, a bunker was built for testing.

The issue at NSC was solved with a garden hose supplying water to the premises grounding electrode. Why or how that mattered is above my pay grade....I have a theory but hey now, I'm just an inspector....and all those years ago I was an assembler.

Now to you Mark K,

You don't even come close to the understanding that an assembler has of the theory of electricity or the NEC. You need to stop interjecting nonsensical BS into legitimate discussion. Your discipline is well defined and does not include anything remotely related to electrical code. Please respect your limitations.

 

[Joe.B]

I think many of us here have a good basic understanding of what a Grounding Electrode System is there to do, and I think many of us (myself included) would agree. If the question posed is what should the code be, or what is the best design would be, many would agree and that would be a great discussion. I took this thread to be a question of what the code says, not what we think about it. I think the code is clear on the issue.

For the discussion of what should be there are too many variables in any given project. What if the house is 30ft from the main with copper or steel pipe? What if it's 300ft? If the house has metal water piping then it needs to be bonded somewhere anyways, but if there is a electrode that qualifies per 250.52(A)(1) then the code says do it in a specific way. I'm betting there's a good reason. They have to draw the line somewhere and usually it's for good reason. Nearby ligtning strikes? Voltage surges from POCO? Car crashed into the house? Handyperson cuts into the wall with a sawzall? Too many possibilities.

There's too much going on to really make any definitive statements, but the code is there and it's probably best to follow it.