you must keep in mind that the voltage drop on electrode connection to earth is only a few feet around the electrode, once you get to a point of about 26feet there is no more voltage drop, think of earth as of billions of parallel resistors, in a three dimensional area, close to the electrode you have very little earth so you have few parallel paths, as you move out from the electrode you add more parallel paths expediently, once you have reached the 26 foot mark there are so many parallel paths that you can consider the earth as zero ohms, this is why the greatest percentage of voltage drop is closest to the rod, at 3' 90% of the voltage has been dropped, at 26' 99.999999% has been dropped, because there is very little soil volume and very few parallel paths, you must think in three dimensions not in two on a plane, also we know current takes all paths back to source, since the earth as a whole is zero ohms then we can expect that this current can travel all the way around the world in every direction from the rod (the reason I did the experiment with the spectrum analyzer mention in a previous post that showed that we can see the 50hz of Europe here around the world), this has been proven in many experiments including one on here, (do a search for "time to eat crow" By Gary).
True, but keep in mind that the MGN grounds (both supplies and returns) as well as the substation grid (return) are in very close proximity relative to the size of the earth. A single ground rod is poor in that as you say the soil around it is a small amount of area. However, POCOs have access to every single rod in a city, which end up being a semi to good conductor as a whole. I have no doubt current can be seen across the globe, but my understanding is current tends to flow near the surface of the earth. This definitely would be true immediately around every ground rod since they are only driven a few feet (generally 8-10).
One thing that I guess could prove this is stray voltage. Even though current might take the whole of the sphere with billions of miles of parallel paths, why does stray voltage occur, even on systems with many ground rods and moist soil? Why is it that dairy cows, fed by rural systems with little load (compared to a city) and many earth connections to protect against lightning, still produce voltage over the surface of the earth? Something as simple as a cow standing a few feet apart on a farm property gives readings over what is claimed to be zero ohms?
Keep in mind that if I cut a ground wire between a rod and an MGN I might get a few volts at most. But that is not the real system voltage. If I cut the neutral going over to the XO bushing under load to a power transformer feeding a distribution line under load I would get about 14,400 volts on a 25kv distribution line. This is approximately the real voltage that is between the substation and any transformer. If we took those same ohmic values to earth as a whole across the system, then plugged in thousands of volts it comes to be very different.
but instead come back to the electrode that is on the secondary of the transformer feeding this primary at the substation.
On a single phase line, but one a 3 phase line current will go up and down. Current in an MGN isn't just looking for the substation grid, its looking for symmetrical cancelation. If I have all my pole pigs one B and C phase, then up the line added pigs on A phase, current would start going down since neutral current as the vector cancellation of the phases (if I worded it right)
So in essences the current flowing in the earth is spread out at a very quick ratio from the electrode and the current drops expediently with all the parallel paths as you move out from the electrode, remember this also means down into the earth in all direction from the electrode, so like I said before, the amount of EMF would be dissipated very quickly as you move out from the electrode, if you add all the other electrodes then you will see very little current at each, but you will get some EMF in close proximity of each rod, how much I would have no idea as all my experiments done in Florida at the University of Florida at Gainesville was done to better understand how electrodes functioned and how current flowed from them, but as you pointed out this also causes the phase conductors up on the pole to not have a net zero cancellation current so I would expect that the EMF would be higher up by these conductors, but because of the distance to them and the fact that the MGN and other neutral paths paralleled with the MGN will also cancel some of the EMF to the ground level, how fast it drops off as you move away should be rather quick, but because of the electrode at the pole you should see a little rise as you move from the middle of a span to the pole, without a gauss meter
EMFs around anyone rod would be higher, but probably not to bad. However, taking earth out of the equation, there is still something that often carries more current. Metal water lines. I have measured 18 amps on a water bond with the main shut off more than once. That is an obscene number. Chances are that's a break in a neutral somewhere outside the structure on OCOs system, but shows the immediate short falls of an MGN. Breaks are just shunted over what shouldn't be. Still, most water bonds measure about half an amp to an amp on average. That current will cause high EMFs on the service feeder, equipment, grounding electrode conductor travelling over to the bond and the pipe itself. Its this connection POCOs love, because it is literally a free conductor.
I would like to point out that it has been estimated that there is millions upon millions of amps of current flowing around and through the earth at any given moment, but since they all have different sources we can't add them together in an additive fashion, but this current is so spread out through all the parallel paths that the current between two points is almost not measurable, this also goes for voltage, you will find it hard to get more then volt if you were to put two rods in at 60' apart then measured the voltage between them, we tried and got only like 400 Milli-volts, the highest I read was about 1.2 volts when I put them in-line with over head power lines but some of this could have been from induction to my wires I used to measure with, everything becomes the parallel path down to the iron core in the earth anytime we inject a voltage into earth.
That is a real scenario, but not all of them. Voltages as high as a few volts have been red on farm soil just a few feet apart. People get shocked all the time from pools, spas, plumbing ect ect. Up to dozens of volts have been read with main breakers open. Mike Holt even has pictures of a gas meter reading a few volts to ground where he explains "that is a huge stray voltage problem". And these few volts shock. In Upstate NY people have sued complaining of shocks on everything bonded to the homes neutral. Farmers all across the US have sued for stray voltage issues. Heck in Minnesota a poco had to require an entire farm town to delta to get it to stop. There are even posts on DIY sites about people being shocked on pools with the main off. Google stray voltage law suits and it will keep you up at night.
Now of course one could argue well maybe its just the neutral and everything attached to it. The earth itself can never energize. Nope. A lot of the cases are the earth themselves. Dairy cows in open fields have been effected by it around nothing connected to an MGN. Experts have been able to measure it with a equipment and rods just a few feet apart.
I disagree, if current used the whole mass of the earth (and it might) then why is stray voltage real, proven and held up in courts all over the US. Why were Dairy land blockers (Ronks) developed?
At higher voltages things change because of the flashover point between the particles of earth, this is why we might see a high voltage line that fell to the ground cause tracking across the surface or a lightning strike, but below a certain voltage it follows the above theory.
one of the problems with the EMF theory is I know of many welders who have worked their entire life welding and have never had any ill effects that could be contributed to EMF, and if anyone there is that would be someone to study it would be them as they work in a EMF rich environment that is so far above anyone Else's exposure level and for much longer times then anyone else.
True, but still bear in mind an MGN is really running around thousands of volts.
I cant speak for welders, or those you have known, but keep in mind everyone is different. But they may have proven EMFs aren't that dangerous.
But like I said before I believe many illness are a gene driven problem, and we all are different and come from many different cultures and environments that may or may not make us prone to certain illness and that is something we cannot change at least yet, but who knows maybe some day they will learn how to modify our genes to take out the bad DNA that may let us live for ever.
Correct, Genes play a role as does environment. The way cancer works is that any substance increases the chance. Yes smokers exist who smoke but never get cancer while others do. It is probability at work governed by genes, but why let a system we designed play natural selection?
