Well casing gounding is an issue in some states ( GEC vs. ECG ) and would be an interesting thread in itself.
To pretest at the controller would be prudent, as Redsy suggests
However, if the concern is a liability issue, read NFPA 70E, get the protective gear on the employee's, prove that it CAN NOT be done de-energized so the CAN NOT back down from the task, and all you need worry about is where to send the deceased's last check.
