Water Authority Conflicting with NEC

[Sparky2791]

Had an inspection from the water authority on a building and they are insisting we remove the Grounding Electrode Conductor connection from the water pipe. Apparently they have concerns about pipe corroding. I sent the guy a snip of the commentary after the 250.52 (A) (1) in the 2017 Handbook and he sent the attached back to me. Trying to understand what they are 'allowing' and ultimately if I need to push back. We already have our electrical inspection so any changes will need to be rereviewed with the electrical inspector. Seems to me they allow a connection from the service panels neutral bar and we can bond the water pipe to a different GEC. Confusing?
Thanks for any replies!

 

[tom baker]

Pipe corrosion is caused by DC current not AC. Have your water authority search the American Water Works Association website for articles on pipe corrosion.
Is the water pipe metallic out to the street? A simple solution is to install a short section of non metallic pipe at the water meter, (leaving 10 ft in contact with earth) which is what is recommended in the best resource on the subject "Effects of Electrical grounding on pipe integrity and shock hazard" by the AWWA Research Foundation
If you can't install a non metallic pipe then its best left to the electrical AHJ and water authority to resolve

 

[Ken_S]

Sounds like something the ahj the utility are going to need to work out

 

[infinity]

The NEC requires that you use a metal water pipe that qualifies as an electrode. The only code compliant method is the make the water pipe not an electrode and then simply bond it.

 

[tom baker]

What is the water service line ? Copper, Ductile Iron. or?

 

[Sparky2791]

The NEC requires that you use a metal water pipe that qualifies as an electrode. The only code compliant method is the make the water pipe not an electrode and then simply bond it

I think that is what the attachment is trying to achieve. But how would you do that exactly, make it not electrode if the NEC requires it to be. Can't make sense of what they are telling you to do that is acceptable to them in the attachment. Ill be happy to make the hange if I understand what it is but the way it is worded does not make sense to me. The way I read it means remove it as a direct connection from the panel to the water pipe and move the direct connection to the building steel than provide a bonding wire connection from steel to water pipe.

 

[infinity]

I think that is what the attachment is trying to achieve. But how would you do that exactly, make it not electrode if the NEC requires it to be. Can't make sense of what they are telling you to do that is acceptable to them in the attachment. Ill be happy to make the hange if I understand what it is but the way it is worded does not make sense to me. The way I read it means remove it as a direct connection from the panel to the water pipe and move the direct connection to the building steel than provide a bonding wire connection from steel to water pipe.

They're saying they don't want the GEC connected to a metal water pipe that exits the building and connects to a common water system. Regardless of that the NEC requires it to be connected. The only option is to make that pipe not a qualifying electrode.

 

[roger]

The way I would handle it would be to notify the electrical inspector and ask him to intervene. I would certainly keep all documentation, names, agencies, etc..., for a paper trail incase you need it.

 

[Sparky2791]

What is the water service line ? Copper, Ductile Iron. or?

Ductile Iron

 

[Sparky2791]

The only option is to make that pipe not a qualifying electrode.

and there in lies the rub. Not possible and comply with NEC 250.50.

 

[wwhitney]

It seems to me the resolution of this conflict would ideally be based on where the point of ownership of the piping switches from the water utility to the property owner. The water utility can then install a dielectric fittings on their side of that service point, and their goals will be satisfied.

Around here water meters and shutoffs are in shallow boxes in the sidewalk (no freezing), and I believe the outlet of the water meter would be the service point. So it wouldn't be that hard to retrofit dielectric fittings.

In a cold climate where the service point is at a shutoff 6' deep near the street, and the water meter is inside the building, then obviously retrofitting a dielectric fitting would be much more difficult.

Or if somehow the water utility actually owns the water lateral to the building, then that's a challenge. As then the metal water piping is present at the building, but not under control of the owner, so the water authority can create a conflict by not allowing connecting a GEC to it.

Cheers, Wayne

 

[wwhitney]

and there in lies the rub. Not possible and comply with NEC 250.50.

250.50 refers to electrodes "present at each building or structure served". So what infinity is proposing is that if you have control of the last few feet of the water lateral outside the building, you could physically change that water piping so that there is no longer a 250.52(A)(1) electrode present at the building. I.e. a 1' section of nonconductive water pipe outside the building, but within 10', so that the metal water piping entering the building is no longer an electrode.

Cheers, Wayne

 

[Sparky2791]

Pipe corrosion is caused by DC current not AC. Have your water authority search the American Water Works Association website for articles on pipe corrosion.
Is the water pipe metallic out to the street? A simple solution is to install a short section of non metallic pipe at the water meter, (leaving 10 ft in contact with earth) which is what is recommended in the best resource on the subject "Effects of Electrical grounding on pipe integrity and shock hazard" by the AWWA Research Foundation
If you can't install a non metallic pipe then its best left to the electrical AHJ and water authority to resolve

Agree a simple solution at the beginning of a project but not the end of one. Plus seems they are concerned about the connection of the GEC to their pipe where it comes out of the ground.

 

[Sparky2791]

250.50 refers to electrodes "present at each building or structure served". So what infinity is proposing is that if you have control of the last few feet of the water lateral outside the building, you could physically change that water piping so that there is no longer a 250.52(A)(1) electrode present at the building. I.e. a 1' section of nonconductive water pipe outside the building, but within 10', so that the metal water piping entering the building is no longer an electrode.

Thanks for the explanation! Makes sense but no longer an option :-(

 

[roger]

Thanks for the explanation! Makes sense but no longer an option :-(

Once again, this is not your cross to bear. Like it or not you have a higher authority telling you what to do so let the other big boy (electrical inspector) take it from there. If he caves so be it, just keep records. Even though the NEC requires it a specific GE is nothing to loose sleep over, you have already said there is building steel available.

 

[Dennis Alwon]

Years ago I had an inspector fail me because I didn't use the gas pipe as an electrode. I argued and then bonded it, The gas company called me up and reamed me out. We got together and finally straightened it out. The inspector gave in..... I had just started doing work then so it was a long time ago

 

[infinity]

Plus seems they are concerned about the connection of the GEC to their pipe where it comes out of the ground.

What's their concern with that connection, it's done per the NEC. As Roger said punt it up to someone else. Tell the water authority that they need to require plastic pipe into the building if they want isolation.

 

[tom baker]

Ductile Iron

The fittings in your picture are flanged and bolted. How are the connections made outside? Likely the first 90 is restrained joint for thrust
All the DI pipe I saw installed by our water crews had bell and spigot joints with a rubber gasket. I seem to recall some type of a bonding wedge for the DI joints. Can you ask your mechanical person? about the underground portion?
From Eng-Tips.com
Ductile Iron pipe is manufactured in nominal 18- and 20-foot lengths and employs a rubber-gasketed jointing system. These rubber-gasketed joints offer electrical resistance that can vary from a fraction of an ohm to several ohms but nevertheless is sufficient for Ductile Iron pipelines to be considered electrically discontinuous. In effect, the rubber-gasketed joints normally segment the pipe, restricting its electrically continuous length.

Pipe joints have electrical discontinuity unless the joints are electrically bonded. DIPRA does not recommend the wholesale practice of joint bonding, but some engineers and owners call for joint bonding.
So likely what is out side does not qualify as a GE, unless you have a bolted flange below the floor and a stick of 10+ DI.

 

[tom baker]

What is the concern of the water authority about the connection to the water line? Its ductile iron, which is cement lined and not very subject to corrosion. AC currents don't cause corrosion but DC does.

 

[tom baker]

They're saying they don't want the GEC connected to a metal water pipe that exits the building and connects to a common water system. Regardless of that the NEC requires it to be connected. The only option is to make that pipe not a qualifying electrode.

So if its DI pipe with bell and spigot then its not electrically continuous, so typically there will be at least one bell and spigot joint to the street main