Multiple Water Pipes

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fitz

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How many people bond to every metal water pipe leaving the building?

I have a water treatment plant project with an influent and an effluent leaving the building. It was my interpretation as required per code according to 250.50 that I have to bond the metal underground water pipe. It was not my interpretation that I would have to bond every metal underground water pipe that is in direct contact with the earth, and so I bonded to the influent piping within five feet of where it enters the building and did not bond the effluent knowing that it has is effectivly bonded via piping. The inspector is requiring us to bond both the influent and the effluent, and said that if we had 100 pipes we would have 100 bonding points regardless of whether or not the piping was effectlivly bonded via piping. What are your thoughts?
 
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I believe that your inspector is correct.

250.50 Grounding electrode system. All grounding electrodes as described in 250.52(A)(1) through (A)(6) that are present at each building or structure served shall be bonded togethwer to form the grounding electrode system.

So if you have three "Metal underground water pipes" that qualify as grounding electrodes in accordance with 250.52(A)(1) you must use each one.

Chris
 
Interestingly enough, Proposal 5-137 Log #2642 was "Accepted in Principle" which would add a new sentence to 250.52(A)(3) which states, "Where multiple concrete-encased electrodes are present at a building or structure, it shall be permissible to bond only one into the grounding electrode system."

I know this is not referring to metal water pipes, but effectively the same premise.
 
I have tried that with other issues in the past and the usual comment back is that the only qualified person would be an electrician, and facility operators are not electricians.

I do wonder if 250.52(7) would cover this as an other local metal underground system.

I can?t recall ever seeing multiple pipes all bonded within 5 feet of where they enter the building. In example we have water treatment facilities and wastewater treatment facilities that have many metal pipes leaving multiple buildings, and according to this interpretation every one needs to be connected to the grounding electrode system.
 
fitz said:
I have tried that with other issues in the past and the usual comment back is that the only qualified person would be an electrician, and facility operators are not electricians.
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I believe the inspector is interpreting this exception wrong. The installation being referred to in the exception is the electrical installation. As long as the operators are not allowed to fiddle around with the electrical installation, the exception applies.

IMHO, as long as you have a continuous and unbroken piping system that goes from inlet to outlet and it is visible the whole way, the piping system can be used to bond the inlet and outlet pipe together.

OTOH, convincing the inspector of this might be more hassle then running a #6 wire from inlet to outlet.
 
It appears to me that i should be including a GEC to each of the domestic water pipes, process pipes, etc.... On some projects this can be dozens of pipes.
 
It appears to me that i should be including a GEC to each of the domestic water pipes, process pipes, etc....
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If they qualify as a grounding electrode, I would say yes.

Again I would try to use the exception to 250.52(A)(1).

Chris
 
There are two requirememts that can often be met with one conductor.
250.52(A)(1) for grounding
250.104 for bonding.
Even if the metal water piping (system) is not a metallic underground water pipe with ten feet in contact with the soil, it has to be bonded to clear a fault.

In a dwelling unit the "ground wire" is most often a bonding wire per 250.104.
And it has to be a metal water piping system. 100 sections of metal water piping here and there are not a metal water piping system.
 
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