Thermostat wiring in shared conduit

[JesseWBryant]

I can't remember the specific reason or if there is a code for it, but why cant you run the low voltage wiring from the thermostat to the condenser unit in the same conduit as the electrical wiring that runs from the service disconnect box to the condenser unit?

Just one of those things where if I am going to tell them its wrong, I want to make sure I know why. Thanks

[JesseWBryant]

Nevermind, I found it. IRC 4204.1.

[Jim Katen]

I can't remember the specific reason or if there is a code for it, but why cant you run the low voltage wiring from the thermostat to the condenser unit in the same conduit as the electrical wiring that runs from the service disconnect box to the condenser unit?

Just one of those things where if I am going to tell them its wrong, I want to make sure I know why. Thanks

The reason is that you don't want line voltage on control wiring.

- Jim Katen, Oregon