How to find hot side of switch

[MstrCarpenter]

I'm not sure what you are trying to articulate.  If there is only one cable coming into the switch box, he can't do what he wants to do, at least not legally.

I'm sorry, I wasn't referring to Marc's desire to add a receptacle, I was referring to a switch leg. On my jobs I usually request a single 15a circuit for ceiling lights and smokes (no receptacles). And unless there's a good reason not to, I prefer power in the ceiling box with a switch leg vs, power through the switch box. When roughed in this way, that circuit can be turned on to provide temporary lighting. And yes, the rules have changed; a neutral is required in (some) switch boxes. So, the switch leg has to be 14/3. To meet that code with 3 and 4 way switches with 3 conductor cable, the line has to be at the first switch and the load on the last. 2 travelers, and the neutral. For some reason, a neutral is not required if the switch controls  a receptacle load, so that switch leg can be 2 conductor as you stated however; You can use the white or gray conductor within a cable assembly for single-pole, three-way or four-way switch loops if it is permanently re-identified to indicate its use as an ungrounded (hot) conductor at each location where the conductor is visible and accessible [200.7©(2)].

Marc, I was also too quick to suggest the receptacle was replaced without removing the connecting tab; the switch wouldn't turn anything off.