Cold Water Ground

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Klbrnt

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Hi. I just took over a project from some previous electricians. The job is about 90% complete.
I have one 600amp main w/ four meters.
I have the ufer ground.
The cold water ground is in question. Each Condo has 125 amp sub feed from main. Then the previous electrical contractor jumped a #6 solid bare copper from sub to the hose bib at entrance of the plumbing. Each Condo has a separate water meter. I dont think this is correct.
I want to run a 3/0 continuous to each hose bib from the main. I dont think you can gound cold water from the sub.
Can any one help me make sense of this. Im not sure.
 
Welcome to the forum.:)

You are correct, you can't connect the grounding electrode conductor for the water pipe grounding elecrode to a "sub-panel".

The grounding electrode conductor must be connected to the grounded conductor at the service disconnecting means.

Take a look at 250.52(A)(1) for when a underground metal water pipe is a grounding electrode and where you must connect to it.

Also take a look at 250.24(A) for where the grounding electrode conductor must connect at the service.

Chris
 
raider1 said:
Welcome to the forum.:)

You are correct, you can't connect the grounding electrode conductor for the water pipe grounding elecrode to a "sub-panel".

The grounding electrode conductor must be connected to the grounded conductor at the service disconnecting means.

Take a look at 250.52(A)(1) for when a underground metal water pipe is a grounding electrode and where you must connect to it.

Also take a look at 250.24(A) for where the grounding electrode conductor must connect at the service.

Chris
Click to expand...

GEC or bond?
 
Klbrnt said:
Hi. I just took over a project from some previous electricians. The job is about 90% complete.
I have one 600amp main w/ four meters.
I have the ufer ground.
The cold water ground is in question. Each Condo has 125 amp sub feed from main. Then the previous electrical contractor jumped a #6 solid bare copper from sub to the hose bib at entrance of the plumbing. Each Condo has a separate water meter. I dont think this is correct.
I want to run a 3/0 continuous to each hose bib from the main. I dont think you can gound cold water from the sub.
Can any one help me make sense of this. Im not sure.
Click to expand...

Wecome to the forum!

A 3/0 from the main disconnect to the metal water pipe entrance from underground is what you want. I assume that a hose bib is an exterior faucet, and if so that will have nothing to do with connecting the electrical system to the earth.

You will want to bond each condo's plumbing systems, hot and cold, to the system. That can be done at each panel 250.104(A)(2).
 
I thought if the GEC went to the main you would not need a 3/0 from each unit. Am I wrong. I am assuming all the metal piping is connected
 
Dennis Alwon said:
I thought if the GEC went to the main you would not need a 3/0 from each unit. Am I wrong. I am assuming all the metal piping is connected
Click to expand...

I think you are right, one 3/0 to the water main. I was not assuming the pipe to be metallically connected though, at least not enough to trust.

And whether enforcable or not, it sure is hard to count on the plumbing into the last unit being bonded while a plumber is working in Unit #2, unless connecting to the local EGC in the subpanel.
 
Cold Water Grounding

Cold Water Grounding

Hey guys thanks for the input. Each Condo has separate plumbing. So, I think each Condo needs to be connected to the main. I am going to look up the Articles suggested. Also I think I will have my local inspector tell me what he wants to see. Maybe he had already told the other electrical contractor that was acceptable. Some how I doubt it. Thank you.
 
Cold Water Bond

Cold Water Bond

Okay, after reading 250.104 (A) (2) I got it. As long as I bond cold water to equipment ground and the GEC goes from Main to cold water entrance within 5ft of building. This should be acceptable. Right?
 
Klbrnt said:
Okay, after reading 250.104 (A) (2) I got it. As long as I bond cold water to equipment ground and the GEC goes from Main to cold water entrance within 5ft of building. This should be acceptable. Right?
Click to expand...
Yes on the second part but I am not sure what you mean by the first part. You cannot bond the water pipes to the sub panels. The water pipes must go back to the main disconnect. You can, I believe, tap into the main GEC with conductors sized for each service. Hope this helps
ry%3D400
 
Dennis Alwon said:
Yes on the second part but I am not sure what you mean by the first part. You cannot bond the water pipes to the sub panels. The water pipes must go back to the main disconnect. You can, I believe, tap into the main GEC with conductors sized for each service. Hope this helps.
Click to expand...

The OP has a single 600 a main service disconnect. Once the GEC is connected the the water main within 5', and supplemented with rod or similar, the grounding is done.

The bonding of the individual units' plumbing is allowed to be done from each sub-panels' EGC terminal, sized per 250.122 for the feeder OCP supplying the sub-panel.
 
Volta said:
The OP has a single 600 a main service disconnect. Once the GEC is connected the the water main within 5', and supplemented with rod or similar, the grounding is done.

The bonding of the individual units' plumbing is allowed to be done from each sub-panels' EGC terminal, sized per 250.122 for the feeder OCP supplying the sub-panel.
Click to expand...

He said each condo has separate plumbing-- what does that mean. Does each unit have it's own ten feet of copper coming in underground????? If not, and it is tied together then I agree otherwise the other plumbing needs bonding to each panel.
 
Dennis Alwon said:
He said each condo has separate plumbing-- what does that mean. Does each unit have it's own ten feet of copper coming in underground?????
Click to expand...
I don't know. I would hope that the water enters into a common room with the service (is there a house panel / meter?) and then is split to the separate units in the slab, or as you conjecture, each separate from the utility.

I would guess that it more likely enters one end unit and travels through each, and is metered locally, other current threads notwithstanding.
 
cold Water Grounding

cold Water Grounding

Hi guys, thanks for all the responses. I just had a walk through on my project with the city inspector. I showed him Article 250. 104.(A) (2) and he agreed that the application was in good standing. You can bond from equipment ground to cold water from a sub. You must ground the Main to cold water within 5 ft of entry. At least that is how the great book was interpreted this time. Im okay with it. Thanks again.:cool:
 
Because there is a main CB which act's as a disconnect you must run the GEC from this main CB. If there were no main CB and you had your four meters tapping off the service lateral inside a wireway then it would be okay to run a GEC from each subpanel.
 
Klbrnt said:
Hi guys, thanks for all the responses. I just had a walk through on my project with the city inspector. I showed him Article 250. 104.(A) (2) and he agreed that the application was in good standing. You can bond from equipment ground to cold water from a sub. You must ground the Main to cold water within 5 ft of entry. At least that is how the great book was interpreted this time. Im okay with it. Thanks again.:cool:
Click to expand...

Good deal! :)
 
erickench said:
Because there is a main CB which act's as a disconnect you must run the GEC from this main CB. If there were no main CB and you had your four meters tapping off the service lateral inside a wireway then it would be okay to run a GEC from each subpanel.
Click to expand...

The four meters without a single main will likely four individual mains to meet 230.71. You would still need to run a GEC to each of these disconnects and not the subpanel they supply. You are allowed to run a single GEC and tap to each of the disconnects 250.64(D) If the four meters are in a single enclosure then it is no different than the single main breaker enclosure - that is the service disconnect enclosure with four mains.
 
What needs to be clarified is: Are you bonding the water piping to the electrical supply, or are you using the underground metal water line as a grounding electrode for the 600 amp electrical service? It makes a big difference...
 
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