Mixing thermostat and power wiring in same conduit whip (from disconnect to Heat Pump unit)

Howard · 2007-02-24T15:06:53+00:00

I'm replacing an old heat pump installation which had the thermostatwiring and the 220V romex all within the same plastic conduit whipgoing from disconnect to the condenser unit.I understand thisn't acceptable per current code. I need a coupleclarifications.1. Can std. Romex wire be used in a conduit or does it need to beindividual wires? (ie THHN)2. It appears that thermostat wiring is permitted within a conduit ifit's insulation is rated for the same voltage as the high voltagecircuit. (ie CL1 220V). However can std. thermostat wire (ie 18/4)be contained in it's own small conduit within the main conduit??