I wonder if the Transformer(s) are connected as MGCN (Multi-Grounded Common Neutral), and there is an issue with the bonding link between Primary and Secondary Grounded Conductors???

There also may be leakage between the direct buried cables, and / or to some other Utility (i.e. Water, Gas, Telephone, CATV).

The scenario sounds similar to applying 120V to an "isolated" driven Ground Rod (Rod is not connected to anything); Earthworms appear at the Ground surface, and start Hula Dancing... wink

-- Scott (EE)

Scott " 35 " Thompson
Just Say NO To Green Eggs And Ham!