Mike,
Are these balanced power supplies for home use permanently installed or is everything cord and plug connected? If they are cord and plug connected, they are outside the scope of the NEC. If they are hard wired, they are a violation of 647.3(1).
As far as the EGC, the code requires it to be run with the circuit conductors. In a low amperage circuit, the impedance increase is not really great enough to prevent or even slow the operation of the OCPD (overcurrent protective device) as long as the EGC is not in a magnetic raceway. In a magnetic raceway, choke effect from running a single conductor in a ferrous raceway could effect the operation of the OCPDI don't see how running this conductor by itself would change anything as far as noise goes. The only source of noise is that from the circuit conductors and the equipment itself. How could running the ground remotely decrease the noise generated by the circuit and equipment.
