parallel path for neutral current created by multiple grounding electrode connections

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sandsnow said:
So I was at my cousins house in Edina, and could swear there was only one HV wire on top of poles in his backyard. I remember making a point to look because at the there had been lots of discussion about POCO earth return. I could be mistaken, it was ten years ago and I might have had "one" beer.;)
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:cool: Yup. Single insulator sticking up from the pole top. A single primary conductor (single phase of 13.8 kV - about 8 kV to ground) with no concern for lightning. . . so the primary is not shielded with a higher grounded conductor. . . so the primary single phase circuit doesn't even run a separate wire grounded neutral. Rather, the PoCo primary return conductor, the conductor running from the local pole top transformer back to the substation, running pole to pole is the very same conductor used as the grounded neutral connected to the 120/240 Volt secondary of the transformer.

The OP tech art of the transformer is exactly what is done here, including Edina, as there has been, historically, one single large PoCo. What the OP tech art doesn't show, what you would have been looking at in Edina, is that the grounded primary conductor would be the middle conductor of what looked like the Secondary (120/240 V) running pole to pole from the transformer to supply more of the neighbor's houses. The two energized secondary conductors go a limited distance and are dead ended at an inline isolation strain insulators, but the neutral continues without electrical discontinuity all the way back to the substation.

This creates parallel electrical paths all over the place, INCLUDING through all the electrical services to the GES and the metallic municipal water piping system.
 
al hildenbrand said:
:cool: Yup. Single insulator sticking up from the pole top. A single primary conductor (single phase of 13.8 kV - about 8 kV to ground) with no concern for lightning. . . so the primary is not shielded with a higher grounded conductor. . . so the primary single phase circuit doesn't even run a separate wire grounded neutral. Rather, the PoCo primary return conductor, the conductor running from the local pole top transformer back to the substation, running pole to pole is the very same conductor used as the grounded neutral connected to the 120/240 Volt secondary of the transformer.

The OP tech art of the transformer is exactly what is done here, including Edina, as there has been, historically, one single large PoCo. What the OP tech art doesn't show, what you would have been looking at in Edina, is that the grounded primary conductor would be the middle conductor of what looked like the Secondary (120/240 V) running pole to pole from the transformer to supply more of the neighbor's houses. The two energized secondary conductors go a limited distance and are dead ended at an inline isolation strain insulators, but the neutral continues without electrical discontinuity all the way back to the substation.

This creates parallel electrical paths all over the place, INCLUDING through all the electrical services to the GES and the metallic municipal water piping system.
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Just wow!!! HV and LV sharing a grounded conductor.

IDK, but maybe since that way of doing things dates back so far back, we get such a cavalier attitude of where to connect EGC and grounded conductors. Cause like I'm told so many times, "It's all the same potential" or "It's all connected together at the source anyway"
 
sandsnow said:
Just wow!!! HV and LV sharing a grounded conductor.

IDK, but maybe since that way of doing things dates back so far back, we get such a cavalier attitude of where to connect EGC and grounded conductors. Cause like I'm told so many times, "It's all the same potential" or "It's all connected together at the source anyway"
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Its like that in all 49 states, Canada and the islands. Hundreds of millions of customers are served this way. Like I tell most people, California has crazy laws to protect you, not harm you.

There is not shortage of stray voltage and EMF. Perhaps we might have a clue why cancer rates are so high in the US?;)
 
mbrooke said:
Its like that in all 49 states, Canada and the islands. Hundreds of millions of customers are served this way. Like I tell most people, California has crazy laws to protect you, not harm you.

There is not shortage of stray voltage and EMF. Perhaps we might have a clue why cancer rates are so high in the US?;)
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Not sure about that truth in all CA laws, but that would be too much of a tangent.

As far as the other thing, yeah I don't get out much.
 
sandsnow said:
Just wow!!! HV and LV sharing a grounded conductor.

IDK, but maybe since that way of doing things dates back so far back, we get such a cavalier attitude of where to connect EGC and grounded conductors. Cause like I'm told so many times, "It's all the same potential" or "It's all connected together at the source anyway"
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Just saw that today at a friends house. Single primary line T's off a pole toward my friends house, 120/240 service drop serving him 10 feet under it. The primary line continues to other stuff but at first Im like, "where is the primary neutral?" Primary neutral is the messenger in his service drop and after the service drop hits him, it changes back to "normal' primary neutral. All I can think is "cheap bastards"

The rest of the day I was looking at other primary lines as I was driving around, and most appear to be 2 ungrounded phases since transformers have 2 bushings and 2 cutouts.

I dont like the MGN system either, however I am sure it cuts costs and we would end up paying those increased costs.
 
electrofelon said:
Just saw that today at a friends house. Single primary line T's off a pole toward my friends house, 120/240 service drop serving him 10 feet under it. The primary line continues to other stuff but at first Im like, "where is the primary neutral?" Primary neutral is the messenger in his service drop and after the service drop hits him, it changes back to "normal' primary neutral. All I can think is "cheap bastards"

The rest of the day I was looking at other primary lines as I was driving around, and most appear to be 2 ungrounded phases since transformers have 2 bushings and 2 cutouts.

I dont like the MGN system either, however I am sure it cuts costs and we would end up paying those increased costs.
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It used to cut costs, but its getting to the point where its costing all of us. The only reason why MGNs were so successful (and still are) was because POCOs use the customer's grounding systems as free lighting protection, equal potential, and the several free neutral conductors that come along with it. When you factor in millions of ground rods, water bonds, cable bonds and indirect bonding to gas lines POCOs get some free conductors to work with.

And yup, everyone gets wide eyed when they figure out the low voltage messenger (often smaller than the LV phases) doubles as the high voltage neutral and ground.

About the only place Ive seen an LV messenger being augmented with a dedicated MV neutral (outside of a spacer cable) was in a small dairy town. A 125% neutral was run in parallel with every LV service cable. I guess the dairy cows didn't like something about the standard arrangement.
 
mbrooke said:
There is not shortage of stray voltage and EMF. Perhaps we might have a clue why cancer rates are so high in the US?;)
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Oh, you really did not just go down that road of no proof and conflicting studies?:D


While you are worried about cancer rates have you considered that are lifespan has done nothing but increase at the same time all this EMF became part of our environment?

I noticed you singled out the US here, that certainly helps support your thoughts of EMF however the US ranks 58 in cancer rates. http://www.worldlifeexpectancy.com/cause-of-death/all-cancers/by-country/

I tried to find out which country leads in cancer rates climbing but I had no luck. What I did find shows cancer rates increasing globally.

Here is a snipit that makes more sense to me than EMF issues

Why Are Cancer Rates on the Rise?

"Populations are growing throughout the world and populations are aging, which is why the number of cancer cases and deaths are going up globally," explains researcher Nathan Grey, MPH. He is the national vice president for global health at the American Cancer Society in Atlanta.

The types of cancer that are -- or will be -- on the rise vary by a country's development status.

In the U.S., for example, rates of obesity-related cancers such as breast cancer and colon cancer are projected to rise. The U.S. is also still facing the lingering-effects of smoking-related cancers. In poorly developed countries such as sub-Saharan Africa, rates of cancers that are related to infection are high. These include cervical cancer, liver cancer, and stomach cancer.
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http://www.webmd.com/cancer/news/20120531/global-cancer-rates-set-to-soar-by-2030

There are countless reasons why cancer rates are climbing, to point to EMF is just baseless fear mongering in my opinion.

One basic reason is that with our longer lifespans we have more time for cancer to develop. Don't get me wrong, I am not saying that is the only reason just that is just one of the many reasons.



Beyond all that ..... I predict no major changes in the current US electrical distribution system in any of our lifespans. :happyno:
 
iwire said:
Oh, you really did not just go down that road of no proof and conflicting studies?:D


While you are worried about cancer rates have you considered that are lifespan has done nothing but increase at the same time all this EMF became part of our environment?

I have no doubt they are. In fact when people were smoking cigarettes in the 50, 60, and 70s all sorts of life extending medical break troughs took place with better insights into healthy living.



I noticed you singled out the US here, that certainly helps support your thoughts of EMF however the US ranks 58 in cancer rates. http://www.worldlifeexpectancy.com/cause-of-death/all-cancers/by-country/


I tried to find out which country leads in cancer rates climbing but I had no luck. What I did find shows cancer rates increasing globally.


They are increasing, that is a fact I will agree with. But the question is why? Increased cell phones, use of plastics, pesticides, stress...? It has to be something.




Here is a snipit that makes more sense to me than EMF issues



http://www.webmd.com/cancer/news/20120531/global-cancer-rates-set-to-soar-by-2030

There are countless reasons why cancer rates are climbing, to point to EMF is just baseless fear mongering in my opinion.

No law enforcement agency works that way. Suspects at a crime scene are not discarded. An investigation takes place to gather evidence as to whether they are guilty or not. Those countless reasons need to be investigated, not ignored. Condemnation without investigation is the highest form of ignorance.


One basic reason is that with our longer lifespans we have more time for cancer to develop. Don't get me wrong, I am not saying that is the only reason just that is just one of the many reasons.



Beyond all that ..... I predict no major changes in the current US electrical distribution system in any of our lifespans. :happyno:
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You have no proof that they aren't cancerous. Notice the key word in your sentence: "conflicting"

Im sure many reason play a role (heck car exhaust has even been called into the ring), but until we can positively prove magnetic fields are none carcinogenic why put up with the risk when some places don't even have to worry about that issue? And lets say they are a slight risk, do you really believe someone will say "yup, they are"?


Im not saying all cancers are from EMF, but how do we know a small bit them aren't?
 
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As for my supporting links, they are self explanatory IMO:


For a long time, physicians were the authority on health. Patients trusted in their doctors' education and expertise and, for the most part, followed their advice. When health concerns about cigarettes began to receive public attention in the 1930s, tobacco companies took preemptive action. They capitalized on the public?s trust of physicians in order to quell concerns about the dangers of smoking. Thus was born the use of physicians in cigarette advertisements
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http://www.healio.com/hematology-on...igarettes-were-once-physician-tested-approved
 
One poco rep informed me the closer one gets to substations, true GEC's disappear inversely proportional to their conversion to neutrals.

That's due to our 'merican system , which as i understand is something of a premium in the world.

So we can assume from this that we've a faction of population sleeping on the proverbial third rail ,

and yes there have been studies done

none of which will ever reach a level of validity to gain legal OR moral clout enough for candles to make a comeback....

~RJ~
 
romex jockey said:
One poco rep informed me the closer one gets to substations, true GEC's disappear inversely proportional to their conversion to neutrals.

That's due to our 'merican system , which as i understand is something of a premium in the world.

So we can assume from this that we've a faction of population sleeping on the proverbial third rail ,

and yes there have been studies done

none of which will ever reach a level of validity to gain legal OR moral clout enough for candles to make a comeback....

~RJ~
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Thanks for the link, that is a good one! :)


I don't believe electricity should be banned (far from it) but simple common sense solutions can aid in the practical safeguarding of people IMO. Electricity is low EMF by nature. If a conductor is carrying equal yet opposite current relative to another one magnetic fields will go to near zero in front of the conductors. Same for a 3 phase circuit.

Gradual change implementing those practical safeguards is the hard part.
 
ActionDave said:
What about allowing more 240V equipment and running more 240V circuits? Keep the 120V to ground, just move to all line to line loads. How would that work out?
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It would only work out at the utilization level, but a good start. MGN primary current would still pass through.


There is one interesting exception. If we connected everything phase to phase on the load side of a 120/208 wye wye transformer bank the primary neutral current would be close to zero. So in theory POCOs could continue to use an MGN system with wye-wye transformers as long as nothing was connected phase to neutral on the secondary. :blink:
 
mbrooke said:
It would only work out at the utilization level, but a good start. MGN primary current would still pass through.


There is one interesting exception. If we connected everything phase to phase on the load side of a 120/208 wye wye transformer bank the primary neutral current would be close to zero. So in theory POCOs could continue to use an MGN system with wye-wye transformers as long as nothing was connected phase to neutral on the secondary. :blink:
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So my idea works in principal?
 
PetrosA said:
Why not?

The example given is where all the meters are fed from one service but with no disconnects located there. I've seen a lot of strip mall type buildings with meter stacks, but the meter stacks also contains the service disconnects, so any panels in the units are then treated as sub panels. I have NEVER seen a service feeding a bunch of meters, then continuing on 25', 50' or a 100' to "individual" units with unfused service feeders in rigid conduit without being encased in some amount of concrete for protection. That design (around here at least...) would put all that wiring and its maintenance in the hands of the POCO, which they likely don't want to deal with. The only thing close to that that I've seen would be when the POCO maintains an aerial quadplex or triplex attached to the back of the building or underground distribution and each owner has an individual drop or lateral to their unit's meter.

Considering the situation where all the meters and main disconnects are located in one place and fed from one service, these buildings are generally built by one investor and the units are rented out. If those units were sold individually, the meter stack would still be common and by nature any individual owner would have to coordinate their electrical system with the other owners there. Whether it's legally allowed to sell off units in a building like that is another question that I don't have an answer to.
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I think you see those that way because of design considerations more so then because code allows/disallows it. Also as you mentioned POCO doesn't want to maintain all the extra secondary distribution - still a design problem not an NEC problem. Strip malls - they change owners/tenants all the time and you may find one large occupancy turn into two smaller ones down the road, or two smaller units turn into a larger one. This may or may not be favorable for centralized location of metering bank.

You can also run the service drop or lateral to one side of a building and route service conductors on the exterior all the way around the building (multiple times if you wish) before entering and are not required to provide overcurrent protection on the exterior portion of those conductors, and there would be no NEC violations. If there were multiple occupancies you could even tap those conductors at each occupancy, or could do something similar for single occupancy as long as each "service entrance" only supplies what can be considered a separate building. Fire walls and fire doors can make separate buildings within what some may call a single building.
 
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