My recommendation is to check NOT to ground, but between system components. IF there is voltage present, I would consider swapping hot/neutral where the power pigtail gets to the first terminal strip or whatever.
08-10-09: Magfan
If there is a difference of potential, voltage, from one chassis to another then there would indeed be a current flow when the two chassis are connected together by ics.
If the AC polarity is reversed and not correct on a piece of equipment that could cause a higher potential, voltage, from that piece of equipment to another piece of equipment where the AC polarity is correct. I would think the difference of potential would be there whether an equipment ground was used or not. Jmo.....
Something that should be made clear when measuring AC leakage of the primary winding of a power transformer the measurement is actually referenced to the neutral conductor.... The neutral being the grounded conductor which shares the same ground plane as the equipment grounding conductor. That is why most people measure from the chassis to the equipment ground of the recept. But the actual difference of potential is being measured to the neutral.
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