Client Refuses U/G Water Piping for Grounding Electrode

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jcook980

jcook980

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Gresham, Oregon
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Electrical Engineer
I have a water utility client who refuses to bond their metal underground water piping to the grounding electrode system at their pumping stations due to bad experiences with stray currents causing corrosion. They claim to be self inspected and exempt from the NEC. While I understand their issue, I am very uncomfortable with their decision not to bond the water lines in their pumping stations.

Comments?
 
While they may be exempt from permit and inspection I do not believe that they are exempt from installations per code.
The Federally owned properties are exempt from permit and inspection as well but it still must be done to code.
 
Re: Client Refuses U/G Water Piping for Grounding Electrode

jcook980 said:
They claim to be self inspected and exempt from the NEC. While I understand their issue, I am very uncomfortable with their decision not to bond the water lines in their pumping stations.
Comments?
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If they are exempt from the NEC, there is some Code they need to follow. Ask for a copy and follow that Code.

If they have an exemption to the NEC ask to see that also.

Being self-inspected does not make them exempt to the NEC by itself.
 
Nothing in 90.2 (A) (B) or (C) addresses "self inspection". I don't see how an AHJ could classify them as exempt in any case.
 
The client is a California water district and they are adamant that they will not allow the attachment of a grounding electrode conductor from the service entrance equipment to their water distribution piping.

I have had a similar problem in the past where an impressed current cathodic protected pipe had a motorized valve added to the pipe. The motor had to be bonded but that effectively disabled the impressed current system. We used a product that was UL listed and provided a DC block / AC fault current pass function. Thus, the DC cathodic protection system was not grounded but the motor was bonded.

My biggest concern is that the metal water piping is likely to become energized by a fault in the pump motor and without a effective fault current path, the OCPD may not open. When I pointed out the maintenance personnel risk, their response was, well, I won't quote them but let's just say they were not concerned.
 
It is common for buildings operated under one branch of the government to be exempt from a municipalities adoption of the NEC.

My city has adopted the 2005 NEC. But all the schools are exempt from the requirements and inspection because they are another government entity. Same with the sanitary district. They may also be exempt from other building codes. They often act as their own AHJ.

Still, the NEC is the standard for safe installations, and not bonding the water pipes would also concern me.

Steve
 
Apparently, this has become a huge issue for the American Water Works Association. Here is a quote from a former chair of their corrosion committee:

"We are actively soliciting the NFPA to change the next revision of the National Electrical Code so it would prohibit the grounding of electrical services to water lines. We feel revision to the NEC is a much better solution to this problem. The electrical service should be grounded by direct ground rod driven at the house. Also, this would be of effect where more and more services are being retrofitted after the fact with plastic and therefore reducing the potential for grounding through this methodology. We feel that the interior piping certainly could be grounded to the rod, but all exterior piping should definitely not be part of this network. Therefore, isolation couplings and dielectric couplings are being encouraged wherever we can in the water industry to reduce the problem of corrosion in mains and deterioration of the infrastructure through the stray current problems."
 
They claim to be self inspected and exempt from the NEC.
I don't buy that at all,
And the claim that bonding to the water line will cause corrosion is bogus.
I have a study by the AWWA that refutes that. PM me with there email and I will discus with them.
Tom Baker, certified water distribution manager
 
Ok what i would do is bond it and take a picture with todays newspaer behind it.Now advise them that you have done this to limit your risk of being sued.Nicely tell them that if anyone gets killed or hurt after THEY remove it that it will be them in court.Certified letter also suggested.
 
I like Tom's solution - instead of condoning the removal of the conductor after inspection, perhaps they can be convinced that their fears are unwarranted.

Tom, is the study in PDF? Can I see it?
 
Tom,

Yes, please post or e-mail a link or the study. The more I think about this the more I want to put something in writing. Both the sealed drawings and specifications (as well as the NEC) clearly direct the contractor to bond to the water piping and the client had three drawing reviews to comment on our design. I have copies of similar projects by other consulting firms for the same client that all show a bond to the water piping. It wasn't until after construction began that this whole issue was raised. In fact, no one from the water district contacted me prior to the direction being given to the contractor.

I feel I should send a letter to the water district's legal department stating my opposition. In effect, the water district has modified the design without the sealing engineer's knowledge or approval. Seems to me the California Engineering Board would be interested in this...

Thanks for all your input!

Jim
 
A self governing/inspecting agency is a double edged sword.Back in the 80`s I worked for the NYC board of education and they had thier own electrical dept.That had NO inspections or over seeing other than the electrician given the job to fix or retrofit something.I remember a High schoo; in brooklyn that flooded in the begining of the summer break 15 ft of water in the basement and all that was done was dry out ,turn it on see what didn`t work repair it and that was it.I transfered to the NYC transit authority and that was a real eye opener.Resistor banks on passenger trains burnt open take them out of service nope just cut a coffee can in 1/2 wrap the burnt resistor tie it with bailing wire and once it got up the hill from the train yard it made service.What happened after was someones else problem.Trouble was I worked a split job 2 days in the yard and 3 days as a road car inspector.I wound up in the hospital after a train exploded under me.I made the 6 oclock eyewitness news when I led a train full of passengers out an emergency exit and went back to fight the fire and was overcome by smoke .For this I got 5 day suspension without pay for endangering myself.But the practice of shoddy repairs continued.I resigned and vested my pension rights a few months later.I can only hope this quakity of work has changed.
 
Even in the message posted by jcook, it says they feel interior piping should be bonded. So just tell them to put isolating couplings on those 16" pipes and you will only bond the exposed interior part :)
 
The report "effects of electrical grounding on Pipe integrity and shock hazard" is by the American Water Works Association Research Foundation. If the utility is a member then they may have it. Its not available as a PDF, its quite interesting at over 200 pages.
corrosion is caused by small amounts of DC current, from power converters, etc. Its very site specific due to soil types
 
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