[quote author="PRR"]..snip..The loads must NOT conduct significant current to ground (green-wire or dirt). Ground leakage should be few-mA at most. This is confirmed by the fact that GFIs generally will not trip on any good appliance.
In the illegal case that there is more current in one side of the CT winding than the other, how much is the drop? 2% at full load. Unless you deliberately load to ground (instead of the other hot pole), you should not be near this; even if you did, the unbalance between 58.8V and 60V is 0.6V, very much less than between 120V and 0V or 60V unbalance. ...snip...
> a whole tearup of your power system
It may not be necessary to change the power lines in the room. Ensure that there is no short to ground, and then switch the black and white wires onto the two hot terminals of the CT winding. Downtime could be 10 minutes, unless bad-design signal boxes smoke at switch-on. ...snip...
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I was thinking, regarding the imbalance, both low and high frequency stuff, and things like line filters with 100nF caps from each side to safety ground. Not that the balanced power makes it worse than the alternative, but just that these sorts of issues limit the extent of the improvement, compared to doing things right at the equipment design level. For example a really terrible piece of equipment in terms of susceptibility might work deceptively well when the balance was nearly perfect, and then deteriorate mysteriously as other loads were put on line.
As far as the tearup: in an ideal world the electricians could work with little disturbance, and then make that changeover as you describe in little time indeed. I suspect though that most of the time, mismanaged as such projects tend to be, it would be significant downtime.
I actually think the whole thing is a pretty good idea, especially if it could be part of installations from the outset, and taken into account by equipment designers. Switching both sides of the line would become standard practice, for one.