I do not think it is relevant to the matter discussed here because if, in principle, the voltage drops across individual ground resistances are known, for example, across the GEC rod ground resistance and across the POCO's neutral ground resistance, the voltage drop across the neutral wire connecting the two resistances is the sum of these two voltage drops.
Mike Holt's video on grounding & bonding
- Thread starter jeff48356
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There is only one voltage drop across resistances that are connected in parallel. That is why such circuits are current dividers and not voltage dividers.
The question is whether the ground resistances in parallel could be reduced to a single resistance for it then be connected between neutral and ground plane with no return path to source via ground. So there should at least be two ground resistances spanned by the neutral wire. Subsequently the two resistances may be considered in series across the neutral.
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They can only be considered to be in series if you are injecting current into the earth near the rods at each end, not if you are applying current between the two electrodes themselves.
In the former case, the actual through-earth resistance between your injection points will be in parallel.
In the latter case, the through- earth path, consisting only of the two electrode resistances in series, will be in parallel with the metallic conductor path.
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Which is exactly what I said.
The through-earth electrode to electrode resistance is just the series sum of the two electrode to earth resistances (not counting other parallel electrodes, metallic paths, etc.)
And if the two electrodes are close enough, the through-earth resistance between them will be measurably LESS than the sum of the two electrode to earth resistances.
Note that the resistance will always be less, regardless of how close or distant they are, but the difference will not be measurable beyond a few zone radii.
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Continuing the reasoning, the voltage drop across the neutral wire during a ground fault may be considered as a sum of the voltage drops of those two resistances-one at GEC ground rod location and the other at the POCO end, instead of that across a single ground resistance and the voltage drop across each would not be equal to 60V..........
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The neutral is bonded to grounding electrodes at both the service equipment and at the utility transformer. That makes the paths via the neutral and the earth parallel paths. There is only one voltage drop and it is the same for both the neutral conductor and the earth.
Don: Suppose there is no grounding of neutral or EGC at the service equipment side. What is the touch voltage then? If now the neutral/EGC is grounded by the GEC ground rod only, with POCO ground rod at other end, does it change touch voltage? If not, why? Thanks.
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Assuming a grounded system, given the typical grounding electrode resistance of hundreds to thousands of times greater than that of the grounded conductor there will be a very very small amount of change in the voltage drop. From a practical standpoint the small change in the voltage drop and the touch voltage will not make any difference.
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