3-conductor NM in 2-conductor application

[ted pierce]

I am running an ordinary 2-way switch loop. However, I want to run 3-conductor NM in case we want convert to 3-way switching in the future. Which 2 conductors do I use for now. Black is one, but should the other be the white with black marking added, or the red? Thanks
Ted Pierce

[Electric101]

Ted, it won't matter which color you use. Of course, like you mentioned, mark the white wire (black tape will do) at both ends to identify it as a "hot" conductor. In this case and if it were me, I would use the black and red for the switch loop and save the white for use as your future traveler conductor. And when I use switch loops, I ALWAYS ensure that the black wire (not the white wire) is used to feed the power to the light fixture. Otherwise you run the risk of confusing others with two white wires at the fixture. (even tho, one may be marked). Personally, I prefer using the red and white as the traveler conductors and the black as power/load on 3-W switch circuits. Good luck!