Water Authority Conflicting with NEC

[infinity]

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

The water pipe in the photo in post #13 is electrically continuous.

 

[tom baker]

The water pipe in the photo in post #13 is electrically continuous.

Yes but I am referring to the underground part, not the flanged connections

 

[Sparky2791]

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

Another its in the NEC but don't do that situation.

 

[Sparky2791]

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.

I did not ever consider that. Thanks for explaining. Been in the electrical consulting business for a long time and always just used the water pipe as a GE without question. Thanks for the explanation and Ill try to find out more.

 

[Sparky2791]

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.

Honestly not sure. First time it has ever come up with them. It was an 'older' inspector. I am allowed to say that because I am 'older' too, LOL. So he may have had an old school mentality regarding this. The NEC even mentions about DC current not being a major problem too in the handbook commentary after 250.52 (A) (1)

 

[Sparky2791]

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

You were correct., exactly the case. Rubber flange at the 90 degree connection taking the pipe horizontal and out to the street so pipe is electrically non continuous. Not having 10' of pipe buried it does not qualify as a GEC.

 

[infinity]

You were correct., exactly the case. Rubber flange at the 90 degree connection taking the pipe horizontal and out to the street so pipe is electrically non continuous. Not having 10' of pipe buried it does not qualify as a GEC.

The water authority wasn't smart enough to know that?

 

[winnie]

I'm confused.

There is a green wire clamped to the pipe, so it seems that the pipe is being treated as a grounding electrode.

But the pipe as installed has insulating gaskets and would not qualify as a grounding electrode?

The water authority doesn't want the pipe used as a grounding electrode?

IMHO if the pipe qualifies as a grounding electrode, then it must be used as such.

If the water authority objects to using their main as a grounding electrode, than they should have a requirement to ensure that the pipe doesn't qualify as a grounding electrode.

If, as installed, the pipe doesn't qualify as a grounding electrode, then remove the GEC and make everyone happy. (Of course you will still need your interior water pipe bonding.

If, as installed, the pipe does qualify as a grounding electrode, then let the authorities hash out their conflicting priorities.

Jon

 

[infinity]

There is a green wire clamped to the pipe, so it seems that the pipe is being treated as a grounding electrode.

But the pipe as installed has insulating gaskets and would not qualify as a grounding electrode?

He's saying that the underground portion of the pipe is not continuous due to the way the sections are joined together so it is not an electrode.

 

[Hv&Lv]

https://portal.ct.gov/-/media/Departments-and-Agencies/DPH/dph/environmental_health/private_wells/37ElectricalGroundsAControversialNecessitypdf.pdf

 

[infinity]

https://portal.ct.gov/-/media/Departments-and-Agencies/DPH/dph/environmental_health/private_wells/37ElectricalGroundsAControversialNecessitypdf.pdf

That document is so full of errors that it's an embarrassment to the Agency that produced it.

 

[wwhitney]

If, as installed, the pipe doesn't qualify as a grounding electrode, then remove the GEC and make everyone happy. (Of course you will still need your interior water pipe bonding.

I haven't double checked the relevant tables, but doesn't that end up being a distinction without a difference?

Cheers, Wayne

 

[winnie]

I haven't double checked the relevant tables, but doesn't that end up being a distinction without a difference?

Cheers, Wayne

If the pipe underground qualifies as a grounding electrode, but the water authority doesn't want it used as a grounding electrode, then you are talking about an expensive fix.

If the pipe underground doesn't qualify as a grounding electrode, but the interior piping still needs to be bonded, then some sort of dielectric union will need to be added. Probably a much less expensive fix.

If you run a wire to bond the interior piping, and don't add a dielectric union, then you are correct, weather required/desired or not, the underground pipe essentially becomes part of the grounding electrode system.

-Jon

 

[infinity]

In this case the dielectric union isn't necessary because the pipe uses rubber that isolates each section of pipe. The elbow fitting going into the ground is electrically isolated from the pipe that is buried so it does not qualify as an electrode.

 

[kwired]

I'm confused.

There is a green wire clamped to the pipe, so it seems that the pipe is being treated as a grounding electrode.

But the pipe as installed has insulating gaskets and would not qualify as a grounding electrode?

The water authority doesn't want the pipe used as a grounding electrode?

IMHO if the pipe qualifies as a grounding electrode, then it must be used as such.

If the water authority objects to using their main as a grounding electrode, than they should have a requirement to ensure that the pipe doesn't qualify as a grounding electrode.

If, as installed, the pipe doesn't qualify as a grounding electrode, then remove the GEC and make everyone happy. (Of course you will still need your interior water pipe bonding.

If, as installed, the pipe does qualify as a grounding electrode, then let the authorities hash out their conflicting priorities.

Jon

Bolts in the flanges are still pretty effective though, probably enough that you can assume you don't really have an insulated joint.

Same with threaded pipes and thread sealants, threads still jam against one another when tightened, the sealant just fills any remaining voids.

 

[kwired]

So water authority doesn't want a GEC or other bonding directly to the pipes, because it may result in enhanced corrosion effects, yet if there is any electrical items in any that piping, sensors, pumps, etc. there is likely still EGC's involved and still end up connecting piping to the electrical grounded conductors, just a little more indirectly. And if said piping leaves the facility and is electrically continuous to other "services" you have connections there as well.

 

[infinity]

So water authority doesn't want a GEC or other bonding directly to the pipes, because it may result in enhanced corrosion effects, yet if there is any electrical items in any that piping, sensors, pumps, etc. there is likely still EGC's involved and still end up connecting piping to the electrical grounded conductors, just a little more indirectly. And if said piping leaves the facility and is electrically continuous to other "services" you have connections there as well.

EGC's would not carry any current under normal conditions. A GEC connected to the water pipe and then directly to the service neutral would allow neutral current to flow on the water piping system under normal conditions. That seems to be the reason for their objection to connecting the GEC to the pipe.

 

[winnie]

Bolts in the flanges are still pretty effective though, probably enough that you can assume you don't really have an insulated joint.

Same with threaded pipes and thread sealants, threads still jam against one another when tightened, the sealant just fills any remaining voids.

I kind of figured that the bolts would provide an electrical path across the flanges. But if they rubber gasket and bolts are sufficient to render the buried pipe 'officially' not qualifying as a grounding electrode, then it makes things simple for the OP. The OP has the problem of two conflicting requirements, that _all_ qualifying electrodes be connected to the GES and that the underground water supply pipe not be connected to the GEC.

If the underground pipe doesn't qualify as a grounding electrode (even if there is some electrical conductivity) then it doesn't need to be part of the GES.

The water authority might require additional dielectric isolation, eg insulating washers on the bolts.

-Jon

 

[wwhitney]

EGC's would not carry any current under normal conditions. A GEC connected to the water pipe and then directly to the service neutral would allow neutral current to flow on the water piping system under normal conditions.

Sorry, not seeing the difference. Either way the pipe is connected to the service grounded conductor. The GEC is just shorter/more direct/possibly lower resistance.

Cheers, Wayne

 

[wwhitney]

If the underground pipe doesn't qualify as a grounding electrode (even if there is some electrical conductivity) then it doesn't need to be part of the GES.

Again, isn't that a distinction without a difference? The pipe will still require bonding.

In other words, if you walk into a building with a conductor bonded to the water pipe, how can you tell if that's a GEC because the underground pipe is an electrode, or just a bonding conductor because the underground pipe isn't an electrode? While there are slightly different rules which could let you tell the difference (e.g. the GE would have to connect with the first 5'), overall they are very similar and would have very similar conductive effects.

Cheers, Wayne