In a 2000 era home in Georgia, I replaced an overhead lighting fixture with a combo ceiling fan and light. (Yes, I reinforced the junction box appropriately.)
The wiring was simple enough, the power supply is via the switch box (now two switches). The question is: For the wiring that runs between the switch box and the fan & light, can I use a single 3-conductor cable instead of two 2-conductor cables? Electrically, it works. Safety and code issues?
Ground and neutral connect through the switch box to both fan and light. I split the incoming hot (black) to supply both switches, then on the outbound side I ran one switched hot for the fan (via the red), and the switched hot for the light (via the black).
It's not just that I'm cheap (I am). The rationale for doing this is that it was easier to pull a replacement single 3-conductor wire rather than pull a second 2-conductor cable.
Best Answer
There's no problem at all with what you've done. In fact, that's the way it's supposed to be done. If you were to use two /2 cables, you'd either be paralleling the neutral (310.4), and/or not running all the circuit conductors together (300.3(B)). Parallel neutrals are not allowed in this situation, so you've actually avoided a code violation by doing it with /3 cable. You've also kept all the circuit conductors in a single cable, and avoided violating that code section.