I wouldn’t mix up 12 and 120 volt wiring in the same conduit. I haven’t found any wiring codes for RVs but both residential and marine codes forbid it. A short inside the conduit would risk damaging if not destroying your 12 volt system. Then there is the confusion it could create. 120 VAC has the hot wire as black, the neutral white and ground green. 12 volt DC the hot is white and the ground is black. I’m using marine grade wire and the folks at West Marine told me to avoid confusion many boaters are using red for the hot wire to distinguish it from the black ground wire for their 12 volt. The latter is the scheme I’m using for my 12 volt wiring. My 12 and 120 wiring never touch each other.