This same problem has occurred in other stores across the country.
The entire store had an issue with the grounding.
You also mentioned that you have not checked the transformer(s)
I have regrounded stores where misc. hard to define computer problems were happening. The procedure was to drive a new copper ground rod, sometimes 2, loop a run of # 1/0 between them, through the gutter beneath the panels, then bonded the ground bars and cans of each panel with bronze lugs on sanded surfaces back to the big 1/0, with #2 into each panelboard. This was also attached to bldg. steel. You have probably already read the thread about grounding transformers from a few days ago, and as somebody else said, this is probably an art. 250 violation. Not saying that it is not a more sophisticated/complex issue, but look at the obvious problems that might be causing your problem to go away when you use grounding adapters; if removing the electronics from the "reference point" i.e. earthing as the Brits call it, removes the symptoms, perhaps you have a lackadasical, casual, almost grounded service. Remember, the code is only the minimum standard...think about it...
[This message has been edited by Almost Fried (edited 10-29-2006).]
[This message has been edited by Almost Fried (edited 10-29-2006).]
