In your friend's case, he's probably looking at a floating system with ground detection on it. The ground detector forces a high impedance ground reference at the center point. In your case, I wonder if they haven't built in a high megohm resistance between their Neutral and case ground. Or some TVS leakage or capacitive coupling between Neutral and Ground. You don't want the two to add up.
Joe
My friend is working in an OR theatre where there is an isolation transformer for each theatre and yes, there is ground current detection monitors in each theatre, as well. He claims his tests add up to 120 V when metering the separate conductors from each to ground. He might be incorrect.
In the article I posted above the images show each conductor metered separately which adds to 120 V. I realize that I might be confused and that the article has nothing to do with either his or my situation.
For my transformer you suggest that you don't want the voltages to add up to the supply voltage. Why?
