The problem with voltage on the grounding is identifying where it is coming from, even a house next door shouldn't raise the voltage of this house if the neutral connections are good, but one connection will, primary neutral to the transformer.
To find this is not that hard, first to distinguish which one we rule out the secondary neutral we do this by forcing a unbalance panel, turn off the main turn off all two pole breakers, now turn off all A or B leg breakers but only one or the other preferably the side with the most load, use a clamp on meter to find this before you turn off the single poles, check the voltage on the side left on, it will read lower then normal much lower in most cases, now check the voltage from the grounding to Earth, if it now has a higher voltage then you have a bad or lost the neutral between the transformer and the house service, if it is lower then you have a bad connection on the primary neutral.
Do's and Do nots!!!!
DO tell everyone on site including children to not touch anything grounded while running these test!!!! make sure you have someone to keep them clear, as serious shock hazards can exist on the grounding.
DO NOT remove any grounding to electrode connection's!!! as you might find your holding the primary voltage in your hand if you live to tell about it.
In all cases treat the grounding as hot until this is resolved as it can kill!!!
A short cut to all this is to get the POCO to take an amprage reading on the primary neutral at the transformer, if it is 0 then there is the problem, but it has to be taken between the transformer and the MGN (power line neutral) other wise they will read the flow from the house grounding.
