Single-Wire--Earth-Return

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It is still being installed in some countries New Zeeland, Australia, Canada, India, Brazil, Africa and Asia for sparsely populated rural areas.

Step voltage can be a problem especially in rural areas where cattle are likely to be present. India sets a maximum of 20V voltage rise at 1m, usually <5V is achieved.
 
The reason I ask is that a National Grid (serving PA, NY, NJ, CT & RI) customer posted a comment on a YouTube channel that the pole serving him has only 2 wires, the 7200v line and the telephone cable and the pole ground ground completes the circuit for the transformer primary. I was trying to find an explanation for what he observes and can't think of one unless the single 7200v wire happened to be a metallic sheathed cable (but I don't know if that is used for anything other than direct burial).
 
Eddie_T said:
The reason I ask is that a National Grid (serving PA, NY, NJ, CT & RI) customer posted a comment on a YouTube channel that the pole serving him has only 2 wires, the 7200v line and the telephone cable and the pole ground ground completes the circuit for the transformer primary. I was trying to find an explanation for what he observes and can't think of one unless the single 7200v wire happened to be a metallic sheathed cable (but I don't know if that is used for anything other than direct burial).
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Are there secondary conductors on the poles too? Utilities use a common conductor for the primary and the secondary neutral.
 
The reason I posed the question is that someone that posted comments on a youtube channel is certain that National Grid customers in his area are supplied electricity via SWER. He observes that utility poles in his area carry only 2 wires, 7200v line and the telephone cable and that circuit ground for the pole transformer is via the pole ground wire. If his observation is correct is it possible that the 7200v distribution is via metallic sheathed cable so that it carries the ground return with it?
 
Eddie_T said:
The reason I posed the question is that someone that posted comments on a youtube channel is certain that National Grid customers in his area are supplied electricity via SWER. He observes that utility poles in his area carry only 2 wires, 7200v line and the telephone cable and that circuit ground for the pole transformer is via the pole ground wire. If his observation is correct is it possible that the 7200v distribution is via metallic sheathed cable so that it carries the ground return with it?
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One really has to see what is being talked about.

Another possibility is that a messenger supports the telco cable, and it is carrying the return current, and the Earth balancing currents.
 
Eddie, please save all of us from pages of speculation. Can you (or he) take any good close-up pictures of the components in question: transformer terminals, especially the grounded-conductor pathway, primary conductor termination and connections, etc.

I have never seen a shielded primary overhead, but that doesn't mean it doesn't exist.
 
LarryFine said:
Eddie, please save all of us from pages of speculation. Can you (or he) take any good close-up pictures of the components in question: transformer terminals, especially the grounded-conductor pathway, primary conductor termination and connections, etc.

I have never seen a shielded primary overhead, but that doesn't mean it doesn't exist.
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You are probably correct on the shielded primary not being used overhead, I have never seen it either. I have asked the youtube poster to come over to this forum where he can post pictures, we'll see what happens.
 
Edie,

Post the link to the comments or video.

My best guess without seeing the actual install:

There is a single primary phase wire, and a 'multi-earth neutral' wire. This 'neutral' (which really isn't neutral) is being used as the 'messenger wire' holding up the phone cable, and thus looks like part of the phone wire. The MEN is grounded with ground rods at regular intervals.

So even though there is a metallic conductor, the earth is acting as a parallel conductor and some current will be flowing in the earth. Single primary plus MEN is IMHO _almost_ SWER, but the MEN acts to limit localized earth potentials.

-Jon
 
winnie said:
So even though there is a metallic conductor, the earth is acting as a parallel conductor and some current will be flowing in the earth. Single primary plus MEN is IMHO _almost_ SWER, but the MEN acts to limit localized earth potentials.
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Jon, doesn't that apply to all distribution circuits? Or are you saying that the messenger is not tied to the source neutral?
 
I never understood why SWER would be used. I guess a very very long run....just thinking aluminum is cheap and it seems like an extra conductor is a pretty negligible cost compared to the other costs - poles, labor, etc....

As has been mentioned, could be that they "stole" a neutral/grounded conducutor from the LV side. I saw that at a friend's house and had to do a double take: The "HV neutral" was stolen from a triplex that connected to another triplex and went to another pole.
 
Eddie_T said:
What is our distribution system grounding called in specific, all I have heard it called is multi-grounded-neutral but I don't work in the trade.
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That it pretty much what its called - MGN. There is also IEC terminology you can read about here: https://en.wikipedia.org/wiki/Earthing_system
There is also lots of ungrounded delta distribution out there, often 4800.
 
electrofelon said:
I never understood why SWER would be used. I guess a very very long run....just thinking aluminum is cheap and it seems like an extra conductor is a pretty negligible cost compared to the other costs - poles, labor, etc....
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SWER is rarely used anymore, and almost definitely not installed anymore, but was probably installed long before aluminum wire was around.

As has been mentioned, could be that they "stole" a neutral/grounded conducutor from the LV side. I saw that at a friend's house and had to do a double take: The "HV neutral" was stolen from a triplex that connected to another triplex and went to another pole.
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That is actually common, especially in the city (Richmond); one grounded conductor used for both primary any secondary neutral purposes.
 
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