Thanks, Guys.
I'm talking specifically about an exterior remote head driven by a remote capable combo unit on the wall immediatley inside. Voltage drop would not be an issue at 3-4 ft.
I saw 150-volt t-stat wire in Graingers.
If the t-stat wire is rated for the higher voltage in the combo unit, I don't know if I can find a code-related issue.
A possible issue may be a non-metallic wiring method above a drop ceiling in a commercial bldg., but it is Romex that is specifically prohibited in that case.
Note:
I am not advocating this practice. I have debated it with another contractor, and am asking for opinions.
