Ok so that's good to know.
Any useful replies to my question?
Well, maybe I take my business to a physics forum.
Sorry you did not find any humor there. I'm assuming your primary questions were in post 3 and I feel they were already answered. Do you still have the same questions?
1. This idea I've read that stray current comes from the electric grid using the earth as a neutral return path (in addition to neutral wire). That they are "dumping" electricity into the ground. Does this make any sense? But I don't doubt these dairy farms are dealing with stray currents. Mike Holt's video explaining the neutral to earth current (NEV) makes more sense to me considering the equipment the animals are making contact with while standing on the ground would be bonded to utility neutral. If a grounding rod is 50 feet from all electrical devices/sources, there are no buried cable ground faults, and no lightning strikes, can we be sure that current will not find its way to an insulated wire connected to that ground rod?
2. If say the NEV was 2v from the pole and the house wiring is grounded, why doesn't that remove the NEV?
The utiility companies are not "dumping" elecricity into the ground. Current will return to the source it originated from, the earth happens to be conductive and if you bond it to a source and then bond another portion of the system to earth you do have a path for current to flow. The reasons for bonding are not to intentionally carry current - it just happens. SWER distribution is the exception as they are intentionally using the earth as a conductor. Using as a conductor is not exactly dumping electricity in the ground,current it is still seeking it's source, but it will take any and all available paths to get there which means if the grounding electrode(s) to your home are in the path of higher current, because they connect to a potentially lower resistance path (back to the utility MGN), you may see higher current on your GEC that is not a part of your premises loads.
Intentionally connecting one point of a voltage system to earth has advantages and disadvantages, the advantages seem to outweigh the disadvantages so that is what we commonly run into is grounded systems. There are times an ungrounded system has advantages, but they typically need better monitoring and even qualified people to monitor them or else when they have a failure they are ultimately becoming a grounded system anyway - but is difficult if not almost impossible to predict what point of the system will become grounded.
Answer to question 2 - earth is at a constant level. The 2 volts to "earth" read at the pole are still on the same low impedance conductor that is connected to both the pole and the house. In fact depending on load in the house you may even see an increase in volts to earth at the house because of voltage drop on the grounded service conductor to the house. You will see "voltage gradients" in the vicinity of a grounding electrode, but earth as a whole has not changed it's voltage potential just a very small area has where a voltage was injected into it.
Bottom line is if you want to "earth" your body then you should connect directly to earth, and avoid "bonded" components of electrical systems or you put yourself in parallel to the system, and will be carrying some (probably a very low level but still some) current of the electrical system.
