A transformer doesn't care if an AC current is obtained by one leg of a
380V 3phase to neutral or in another way because the primary and
secondary windings are electrically isolated.
When a conflict occur it's because a circuit that's connected to the AC
line is not isolated from it (or by original design or because of a
failure) and a virtual zero point stops to be that a new path is
created. In such situation, an extra separation transformer can fix the
problem althoug when the involved power is rather big such solution is
a bit bulky and finally not very cheap.
Actually, to avoid GND/Neutral conflicts and for safety reasons, a
circuit that's not isolated from the AC line (like most of domestic
electrical appliances) should be at least isolated from ground
(including the circuit virtual GND points) and confined inside a
protected enclosure.
A metal cabinet like that of an amplifier (that's also connected to
antennas) must always be connected to GND and never connected to the AC
line through a virtual zero point or directly to a neutral wire.
73,
Mauri I4JMY
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