City water network creates parallel neutrals (parallel conductors)

[electrofelon]

I think you would need to run two cables. The concentric is not "insulated" but rather "covered". Seen older cables where the concentric not even covered it is the outer layer of the cable.

Yeah I wasn't clear on what tortuga was saying there, def need two cables for a MV delta system. You really appreciate an MGN when you have a long single phase MV run and can use just one cable. I've done several around 2000 feet , from both Delta and wye systems ( two and one CN cables respectively). If all the MGN haters did one of each, I think they would change there stance on it .

 

[jim dungar]

Yes. Transmission lines are usually from a delta source, that fourth wire has no place to connect to at the source other than metal frame and is grounded multiple times but is called a shield wire more so than a neutral or grounded conductor.

MGN systems are usually from a wye secondary and is also the neutral of the system.

But the discussion at that point was about distribution feeding an end user, not transmission systems.

When I studied transmission lines we called to top conductors 'static wires'. the term Shield was used with conductive layers wrapped around other conductors.

 

[GoldDigger]

But the discussion at that point was about distribution feeding an end user, not transmission systems.

When I studied transmission lines we called to top conductors 'static wires'. the term Shield was used with conductive layers wrapped around other conductors.

Even not carrying current, I wonder if the capacitance from hot wires to static wire factored into transmission line impedance calculations?

 

[jim dungar]

Even not carrying current, I wonder if the capacitance from hot wires to static wire factored into transmission line impedance calculations?

Yes it does. Line configuration and orientation is important. On certain voltage systems it is not uncommon to see the phases moved around on the poles and towers every so often as part of controlling the impedance.

 

[kwired]

Yes it does. Line configuration and orientation is important. On certain voltage systems it is not uncommon to see the phases moved around on the poles and towers every so often as part of controlling the impedance.

I know of a location where I see they swapped phase positions on a transmission line and often wondered why. This very well may be it.

 

[mtnelect]

Yeah I wasn't clear on what tortuga was saying there, def need two cables for a MV delta system. You really appreciate an MGN when you have a long single phase MV run and can use just one cable. I've done several around 2000 feet , from both Delta and wye systems ( two and one CN cables respectively). If all the MGN haters did one of each, I think they would change there stance on it .

It's the "Collateral" damages it causes to homeowners that is the problem. Attacking underground utility lines, causing leaks.

 

[mtnelect]

From the Southern California Gas Company

 

[electrofelon]

It's the "Collateral" damages it causes to homeowners that is the problem. Attacking underground utility lines, causing leaks.

How many of these situations have you actually come across? I can't recall a single stray current, damage to piping, collateral damage issue, etc issue my whole life and career.

 

[mtnelect]

The street that I'm on has been plague with multiple natural gas leaks. When the street was constructed the gas company decided too burry the mainline in the parkway and not in the middle of the street. I have been outside with the gas company repair crews several times, observing their repairs. Each time I have a discussion with the repair crew they believe it's the soil make-up that is causing the damage to the natural gas pipes.

When I saw the attached brochure from the Gas Company about not bonding to their natural gas lines, because it will cause leaks, I connected the problem we are having. Originally, I thought it was the landscape being watered causing the natural gas line to rust.

 

[garbo]

In that one case of the open neutral, I measured more than 1 amp on a ground rod. I shut everything down and didn't do further testing at the risk of frying things and having a fire start, of course. But I did snag that measurement on rod and was pretty amazed that so much current could run through the soil. Good, moist, compacted soil can provide good connections to the rod though. There are so many parallel connections in the earth that a lot of current can run. Tapping into it is the hard part, but the parallel paths are there once you do tap in. Of course we should NOT be using the earth as a conductor, either, and should be using intended cables only. While some current on the earth is inevitable in our multi-grounded system, it can be limited through good and proper practices.

Most important: run much larger neutrals or add another line (5-wire system) as a parallel neutral. Ensure all neutral connections are permanent and resistant to damage/corrosion/break from moisture and vibration and other movement over time. Use electronic devices to isolate, identify/clear faults, and add impedance where possible to improper earth/pipes/etc paths, thereby forcing current back on the correct path. Don't create parallel conductors that take a different physical path - this splits current and causes magnetic fields, the transformer effect, health risk, induced current, etc.

We can get there and keep improving. This is a great discussion. I'm very thankful for it.

Here is a petition to change NEC/plumbing codes to end the issue of using the water pipe/sewer pipe as a low-impedance parallel conductor.

Petition Change National Electric Code and Plumbing Code to End Using Water Pipes as Electrical Conductors

Change National Electric Code and Plumbing Code to End Using Water Pipes as Electrical Conductors

www.ipetitions.com

If anyone here likes the wording of the petition enough to be willing to publicly sign it, let me know. I'd be happy to list your name and company as well. Thanks for your support!

You must have great moist soil to ever get over one amp of current flowing thru it. When they first started requiring a ground rod for services several times I attempted to see how a 25 & a 100 watt incandescent lamp would work. Best case was the 25 watt lamp gave out as much light as a miniature flashlight with old almost dead batteries. Just ran the 120 volt energised test clip from test lead set and the dog round wire for the grounded conductor. Ground rods in the big City driveways surrounded by concrete had the highest resistance so produced the lowest light.

 

[zbang]

ISTR an illustration from Richter's Practical Electrical Wiring (in the 1960s) that had a ground rod tester for farms- an ammeter with a 15 amp fuse and a switch. They said you should get at least 5 amps between between hot and the ground rod out past the service.

I also remember, as a kid, thinking this was somewhat dodgy.

 

[GoldDigger]

ISTR an illustration from Richter's Practical Electrical Wiring (in the 1960s) that had a ground rod tester for farms- an ammeter with a 15 amp fuse and a switch. They said you should get at least 5 amps between between hot and the ground rod out past the service.

I also remember, as a kid, thinking this was somewhat dodgy.

One problem is that it is actually testing the series impedance of the ground rod and the POCO ground electrode at their transformer. Where the POCO impedance is potentially lowered by an other GES grounds you may still have connected at the time.

 

[Solar Guy]

Not sure I understand this scenario - with an open neutral, 120V circuits send their current back to the panel, to the GEC bond, to the water pipe, to the neighbor's house, to her GEC bond, through her neutral back to the transformer? Wouldn't the voltage drop be hideous, and start a troubleshoot why the 120V circuits aren't working but the clothes dryer is?

 

[GoldDigger]

Not sure I understand this scenario - with an open neutral, 120V circuits send their current back to the panel, to the GEC bond, to the water pipe, to the neighbor's house, to her GEC bond, through her neutral back to the transformer? Wouldn't the voltage drop be hideous, and start a troubleshoot why the 120V circuits aren't working but the clothes dryer is?

A truly open neutral, which forces all unbalanced current to return through the parallel ground to POCO neutral path will cause voltage drop. But the resistance of metallic water pipe system will be very low. Do not confuse the high resistance of earth electrodes with the low resistance of that metallic path.

A voltage drop on the order of 5% is allowed on the ungrounded conductors, and will not be glaringly apparent in the neutral path either.

A lost neutral without this parallel path, relying instead on conduction through two or more earth electrodes, will indeed cause obvious problems, but will not necessarily cause 120V loads to stop working. The voltage offset may well destroy sensitive electronics (and even incandescent light bulbs) on the opposite side of the circuit.

 

[LarryFine]

A truly open neutral, which forces all unbalanced current to return through the parallel ground to POCO neutral path will cause voltage drop. But the resistance of metallic water pipe system will be very low. Do not confuse the high resistance of earth electrodes with the low resistance of that metallic path.

Metallic municipal water piping systems are becoming a thing of the past; most new are plastic now.

 

[jaggedben]

Not sure I understand this scenario - with an open neutral, 120V circuits send their current back to the panel, to the GEC bond, to the water pipe, to the neighbor's house, to her GEC bond, through her neutral back to the transformer? Wouldn't the voltage drop be hideous, and start a troubleshoot why the 120V circuits aren't working but the clothes dryer is?

No. Most residential distribution transformers handle several houses, meaning the distance between the houses may not add much of any real distance to the transformer, which might be down the block. And as long as the bonds to the water pipe are good at both houses, a continous metal pipe network itself makes a very good conductor, as good or better than the service drop. So no, change in L-N voltage could easily be no greater than normal fluctuation of utility voltage.

Metallic municipal water piping systems are becoming a thing of the past; most new are plastic now.

Just because new ones are not being installed doesn't mean the old ones are going away quickly.

 

[LarryFine]

Just because new ones are not being installed doesn't mean the old ones are going away quickly.

Definitely. In cities and existing neighborhoods, for sure.

 

[EMFExplorer]

That doesn't seem very high to me.

As little as 18 millivolts of contact current to the human body has been associated with cancer in numerous well programmed studies. https://www.electrahealth.com/The-P...d-With-Residential-Magnetic-Fields_df_60.html

It's known that earth is a poor conductor in the micro sense, but a great one in the macro sense.


Don't we strive for that now?

Yes, and that's a good thing to keep encouraging.

That seems lie very expensive overkill for relatively little gain.

Doing this has increased milk production in dairy cows and prevented birth defects, stillbirths, infections, etc enough in a single farm to pay for the change in a year. The cost savings of hospital bills for cancer and many other health issues in humans would pay for it in no time at all.

Don't we strive for that now, too?


You're under the impression that eliminating parallel neutral-current pathways will somehow improve the conductivity of the intended pathway? How does that work?

That's not at all what I said. What I said was eliminating parallel paths will force the current to take the desired/intended path - the conductor. We are supposed to use wires for electricity. If the wires aren't big enough - upgrade them. Putting the current into the ground by driving rods instead of upgrading the infrastructure is like drilling holes in sewer lines to stop them from backing up. Sure the toilets will flush, but people will get sick.

Where are these catastrophic events occurring?

Contact current is the worst for health. Magnetic fields are probably secondary. Refusal to appropriately size neutrals and have detection for and resolve neutral to earth faults results in humans and animals being exposed to high frequency electrical current which induces metabolic problems like cancer. It causes many types of diseases.

I haven't looked it over yet, but I think eliminating electrodes will cause more hazards than it may eliminate.

We are only advocating eliminating the use of metal water pipes as electrodes and simply using rods only. This way there is at least not terrible magnetic fields in residential neighborhoods 24/7/365 simply because "that's the way grandpappy did it."

 

[jaggedben]

As little as 18 millivolts of contact current to the human body has been associated with cancer in numerous well programmed studies. https://www.electrahealth.com/The-P...d-With-Residential-Magnetic-Fields_df_60.html

That paper seems to contain some significant misunderstandings or oversimplifications of electrical theory that make me question its methodology. Notably it talks about a contact voltage as if it's a voltage to ground rather than between the two contact points. Also it seemingly defines a Voc in terms of current: a Voc is by definition for an open circuit, meaning no current is flowing.

That's not at all what I said. What I said was eliminating parallel paths will force the current to take the desired/intended path - the conductor. We are supposed to use wires for electricity. If the wires aren't big enough - upgrade them. Putting the current into the ground by driving rods instead of upgrading the infrastructure is like drilling holes in sewer lines to stop them from backing up. Sure the toilets will flush, but people will get sick.

With the super-low voltages you claim are an issue it is probably not possible and certainly not affordable to upsize wires enough to avoid such voltages on the parallel path through the earth. In any case many if not most cases of significant current taking parallel paths are due to connection failures and not conductor sizes.

Contact current is the worst for health.

Maybe. A single paper does not establish that.

We are only advocating eliminating the use of metal water pipes as electrodes and simply using rods only. This way there is at least not terrible magnetic fields in residential neighborhoods 24/7/365 simply because "that's the way grandpappy did it."

Eliminating the NEC requirement to use the metal water pipe as an electrode will do nothing to change the situation as long as we are still required to bond metal water piping systems and as long as such systems are not electrically isolated from the underground networks. While many older homes have not been updated, the NEC is now usually understood to require that metal water piping be bonded within 5ft of entry of the home.* If that is done properly, along with proper GEC and EGC installation, as well as modern appliciances that don't use the neutral for bonding, then there will be no voltage between exposed conductive parts generally anywhere within a home. Everything exposed will be bonded to a single point at the service panel with no current flowing on any condutive material between them, meaning they will be at the same potential.

Not bonding metal metal piping, or isolating underground piping from piping in a building, risks creating lethal shock potential between exposed metal surfaces. You will never convince NFPA to adopt such changes, and for very good reasons.


I suppose you could also advocate for plastic water piping systems. But personally, with all we are learning lately about microplastics in people's bodies, I'm not convinced that changing water piping to plastic doesn't present a greater health risk than what you are claiming to be a problem here. Rather the opposite, to my admittedly non-expert knowledge.

*I've actually argued that the NEC doesn't require the GEC to the water pipe to terminate within 5ft of entry. But for the purpose of allaying the purported problems here, the common interpretation of the NEC is a good thing because it means that any neutral current taking the water pipe as a parallel path is occuring almost entirely outside the building, and thus not inducing magnetic fields or voltages on water piping within the building.

 

[LarryFine]

Plus, it seems that eliminating common water-pipe bonding would inject more current into the earth.