Well, more of a 'tingle' than a 'shock.' I'm stumped and looking for an explanation ....

First, understand that everything is NEW. From the service to the appliance, all new. Even the power transformer is new.

Today, in seeking to relocate the disconnect serving a ground-source heat pump, I got a mild shock. Almost a gentle tingle. I even felt this from the neutral, as well as the hot lines (on the line side).

Meter readings were in the area of 45-50 vac. Quite a feat for something fed from a new Square-D I-line 3-phase breaker. While I've seen meter 'ghosts,' I've never felt one before. 480v, 60a, undersize neutral for the controls.

Even if the breaker were somehow 'leaking,' what would put the voltage on the neutral? Mind you, this happened with the wires disconnected from the unit, and I was not in contact with the unit at the time.