Bonding subpanel to electrode

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M. D. said:
I read it the same way as Dennis ,.. there is nothing wrong with bonding the EGC at the sub panel to water pipe electrode ,.. the interior gas pipe the,..metal hot air ducts ,..the air lines,. the building steel ,..the metal waste pipes ,..bond it all baby the more the better


Not only will it not interfere it will provide a lower overall impedance under fault conditions ,...assuming a complete metal piping system In this case two paths are better than one.
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As stated earlier, the Gec is NOT for fault conditions to open the ocpd. Only the egc is. GEC utimately is to get the ligthing to earth via the ge. Why would one want to intentionally have a parrallel path of fault current on the any portion of the water pipe?? Read the definition of the gec and and tells you its connected to the service. It tells you also what the egc is for.
 
brother said:
Did you read 2005 NEC 250.36(F) and rest of the articles i quoted. Remember the op said this was a SUBPANEL, not the Main service. Doing this is a code violation, and a GEC is not to be used to open an ocpd.
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250.36

High-Impedance Grounded Neutral Systems

How does this section even apply to the OP example.

It doesn't. :smile:
 
I am confused here with the replies.

The way I read the OPs question is as follows....Service installed in dwelling, all proper grounding in place, sub panel added within dwelling, required bonding for metal water pipe system run to the sub panel NOT the service.....


I assume there is already a grounding electrode system of some sort installed and that the water pipe comming into the house is plastic. I base this on the fact the the OP says he is bonding the water pipe NOT using it an electrode.


I am not sure this is allowable.
 
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brother said:
As stated earlier, the Gec is NOT for fault conditions to open the ocpd. Only the egc is. GEC utimately is to get the ligthing to earth via the ge. Why would one want to intentionally have a parrallel path of fault current on the any portion of the water pipe?? Read the definition of the gec and and tells you its connected to the service. It tells you also what the egc is for.
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If there is proper bonding and grounding at the service and this connection is in addition to it and the pipe is a complete metal system it will lower the impedance .. The grounding electrode conductor from the service is connected to the water pipe and to the system neutral .. How could it not.???
 
I believe terminology is confusing brother! The "bonding jumper" connected to the equipment grounding conductor bar of the "sub panel" is not a violation. If that were if fact a GEC then it would be - he keeps saying GEC when it is truly a bonding jumper.
 
barbeer said:
I believe terminology is confusing brother! The "bonding jumper" connected to the equipment grounding conductor bar of the "sub panel" is not a violation. If that were if fact a GEC then it would be - he keeps saying GEC when it is truly a bonding jumper.
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who has said it was a bonding jumper and not a gec?? and I was under the impression like someone else that there was no gec installed at the service. Maybe it is as you say, but we will have to wait for the op to respond and clarify.
 
brother said:
who has said it was a bonding jumper and not a gec?? and I was under the impression like someone else that there was no gec installed at the service. Maybe it is as you say, but we will have to wait for the op to respond and clarify.
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Very first line of this thread....
A bonding jumper from the cold water pipe is run to a subpanel where this bonding jumper is connected to the terminal bar for the grounding conductors.
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electricmanscott said:
Very first line of this thread....
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I suppose I over read that one, I stand corrected. ;) it was the rest of the context of the op posts (facilitate the ocpd by way of the the water pipe etc.)that lead to me to think that the service panel was not bonded like it was suppose to be, but there i go assuming things cause he has not stated that either.

One would not need to run another jumper (or anything else) to the water pipe seeing it would be already bonded at the service panel with the gec as well. i suppose this gec is serving 2 purposes at the service panel from the water pipe. In my opinion one should not want to willfully use the water pipe to carry current past the service gec.
 
Another point to consider here: If it's true that the waterpipe is making an electrically continuous connection all the way back thru the remote panelboard on through to the main service equipment, hopefully it would have had to be sized to carry the full ground-fault current of the electrical system back through this notorius 4th wire (egc) on through to the grounded conductor. This would need to be sized more in line with 250.66, than 250.122. Hopefully the electrician did not use 250.122.

I hope the original poster of this thread clears the details up for us. :smile:
 
It sounded to me like the original poster was under the impression that shunting some of a ground fault current to the bonded water pipe would rob the breaker of some of its needed fault current. But it would not.

Karl
 
OP's Question: Does the use of this bonding jumper dissipate fault current back to the system neutral thereby interfering with the opening of the OCPD on a fault?


No, The Feeders EGC will facilitate this provided it is a low impedence path back to the source. Obviously, things can be installed incorrectly to complicate this but to answer your question...No.
 
radiopet said:
OP's Question: Does the use of this bonding jumper dissipate fault current back to the system neutral thereby interfering with the opening of the OCPD on a fault?


No, The Feeders EGC will facilitate this provided it is a low impedence path back to the source. Obviously, things can be installed incorrectly to complicate this but to answer your question...No.
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That goes to my previous question, why would one want to create a parrallel path for this fault current on the water pipe, when there is a possibility it can have a lower resistance than the ground wire in the panel. I would not do this even if its not the gec.

Bonding is one thing, assuming that the bonding jumper is sized to not be lower resistance than the egc.
 
smallfish said:
A bonding jumper from the cold water pipe is run to a subpanel where this bonding jumper is connected to the terminal bar for the grounding conductors. The feeder equipment grounding conductor from the service panel is terminated to this bar as well.
The feeder neutral is isolated from this terminal in the subpanel.
Does the use of this bonding jumper dissipate fault current back to the system neutral thereby interfering with the opening of the OCPD on a fault?
If this is a violation to code, is there a section in the code that applies?
Thanks
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As long as your feeder ground is connected and continuous I dont see how any other grounds could reduce the fault current from flowing.
 
quogueelectric said:
As long as your feeder ground is connected and continuous I dont see how any other grounds could reduce the fault current from flowing.
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Right ,.. and not only that it should , in theory, have less difficulty getting back to the source and that should help clear the fault in less time.

Brother back in the eighties we were required to make the metal water pipe system electrically continuous , we were also allowed to use the cold water pipe as an equipment ground ,..it has been removed , Why? plumbing practices changed and the electrical code could not prevent a plumber from installing plastic..

What if there were a 60 amp instant hot water maker and you had a # 6 equipment ground from the sub panel run in EMT to the unit and the water piping system is metal ?? There is no reason to be concerned with this . Now you would have the EMT equipment ground and the # 6 bonding the water system .. there is no restriction and I think the more the better.
 
brother said:
That goes to my previous question, why would one want to create a parrallel path for this fault current on the water pipe, when there is a possibility it can have a lower resistance than the ground wire in the panel. I would not do this even if its not the gec.

Bonding is one thing, assuming that the bonding jumper is sized to not be lower resistance than the egc.
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Do you not already tie all the EGC's in a dwelling together as well and it seems to present no issues in regards to clearing the OCPD?
 
Hitchhiking on an equipment grounding conductor from the main grounding electrode system through a remote panelboard to another piping system is not a good practice.

Only one grounding electrode system should be used with everything that's required to be grounded connected to this same grounding electrode system. If more than one electrode is used, they should all be bonded together to form one common electrode. And not by the egc, either.
The system described in this thread is not a common electrode system.
Grounding electrodes should never be relied upon to provide the ground-fault return path for equipment. Their intended function is different.

I agree that it's desirable to provide the lowest impedance path to help in clearing faults. Improperly using equipment grounding conductors to serve as bonding connections for two remote electrodes is not good workmanship.
 
I believe the article that really prevents this set up is 250.104(A)(1) NEC 2005. There are exceptions, but i do not believe any of the op's thread fall under them.

Even though it may not be a gec, the bonding jumper is still used/installed at the service panel, its like the gec is serving 2 purposes here. So running a 'bonding jumper' to the water pipe from the subpanel is a violation under this article when its the same building.
 
M. D. said:
Right ,.. and not only that it should , in theory, have less difficulty getting back to the source and that should help clear the fault in less time.

Brother back in the eighties we were required to make the metal water pipe system electrically continuous , we were also allowed to use the cold water pipe as an equipment ground ,..it has been removed , Why? plumbing practices changed and the electrical code could not prevent a plumber from installing plastic..

What if there were a 60 amp instant hot water maker and you had a # 6 equipment ground from the sub panel run in EMT to the unit and the water piping system is metal ?? There is no reason to be concerned with this . Now you would have the EMT equipment ground and the # 6 bonding the water system .. there is no restriction and I think the more the better.[/QUOTE]


This is an excellent point. Mechanically there would be no difference, and electricity certainly doesn't discriminate between the two.
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acrwc10 said:
M. D. said:
Right ,.. and not only that it should , in theory, have less difficulty getting back to the source and that should help clear the fault in less time.

Brother back in the eighties we were required to make the metal water pipe system electrically continuous , we were also allowed to use the cold water pipe as an equipment ground ,..it has been removed , Why? plumbing practices changed and the electrical code could not prevent a plumber from installing plastic..

What if there were a 60 amp instant hot water maker and you had a # 6 equipment ground from the sub panel run in EMT to the unit and the water piping system is metal ?? There is no reason to be concerned with this . Now you would have the EMT equipment ground and the # 6 bonding the water system .. there is no restriction and I think the more the better.[/QUOTE]


This is an excellent point. Mechanically there would be no difference, and electricity certainly doesn't discriminate between the two.
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How do you justify, or interpet article 250.104(A)(1)?? The only time u allowed to bond the metal piping at another panel(sub panel) is a building with multiple occupancy and multiple buildings or structures etc..

So as far as physics/ mehcanically maybe there is no difference (i think there is) , but its definitely a code violation.
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