[RE-wrenches]hum

[Sharkey]

	John;

	A lesson in "common mode" as we call it in broadcast engineering. It could
be that the enclosure is acting like a shorted winding in a transformer.
Great amounts of current (but little voltage) can be induced in a metal box
that contains only one conductor in a circuit. The fact that the conductor
enters one end and exits the  opposite compounds the problem by a factor of
two.
	Seems to me that I remember reading something in the NEC about individual
conductors in an enclosure, and it wasn't good. Practical application of
this could result in currents in excess of what the enclosure can
withstand, and it was purported that even small conductors could induce
significant heat in the metal of the box!
	I think we're getting close to the source of your hum. Please let us know
if you decide to re-wire, and if that solves the problem. This is valuable
information for all installers!

	-S
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