Unusual Situation

[romex jockey]

If the voltage offset is present with the main breaker off and there is not a metal water pipe connection to another customer, a strong possiblity is that POCO has lost their metallic multiply grounded neutral (MGN) connection on the primary side of their transformer. The unbalanced primary currrent flowing through their local earth electrodes causes an offset of voltage between the secondary neutral and earth ground.
This potentially a very dangerous situation and would have to be corrected by POCO. If it is not an actual break but just a marginally sized primary neutral, POCO may want to insert a ground isolator on the customer's neutral instead of actually fixing the problem. 14 volts is more than is usually appropriate for a ground isolator.

so would one check with the neighbors to verify this?

~RJ~

 

[GoldDigger]

so would one check with the neighbors to verify this?

~RJ~

If there are neighbors on the same transformer, that would be one thing to double check for verification.
To me the most unambiguous diagnostic is to measure the voltage at the POCO ground electrode at the base of the pole holding the transformers. If it is offset compared to remote earth (screwdriver driven in at a distance, also far from customer electrodes), then there is a POCO MGN problem.
It could still be the result of return current from a user of that transformer who has a bad service neutral. But that would vary as each of the users on that transformer open their main breaker.

 

[romex jockey]

If there are neighbors on the same transformer, that would be one thing to double check for verification.
To me the most unambiguous diagnostic is to measure the voltage at the POCO ground electrode at the base of the pole holding the transformers. If it is offset compared to remote earth (screwdriver driven in at a distance, also far from customer electrodes), then there is a POCO MGN problem.
It could still be the result of return current from a user of that transformer who has a bad service neutral. But that would vary as each of the users on that transformer open their main breaker.

so it could be a bad poco MGN, or a bad noodle anywhere on the 'user' end ?
how to differentiate Gold one??

~RJ~

 

[GoldDigger]

so it could be a bad poco MGN, or a bad noodle anywhere on the 'user' end ?
how to differentiate Gold one??

~RJ~

If there is still voltage when all users of that transformer are turned off, it is an MGN problem. There will still be the magnetizing current in the primary of the transformer even when the secondary is totally unloaded. The exact behavior will vary depending on whether the POCO neutral is bad at that pole or at some point upstream with other transformers on the bad segment.