I've got a 25 year old house, whose light switches I'm converting over to a powerline protocol called INSTEON (see
Two of the bedrooms are on one circuit breaker (the whole rooms: lights, outlets, the whole shebang). Each room has a single switch controlling the lights in that room. I pulled a light switch out this evening, planning to replace it, when I saw there was no neutral in the junction box (the INSTEON switches require both hot and neutral). At first I expected to find neutral in the wall behind the box (I was guessing they had, for some reason, routed hot through the box and to the switch while leaving neutral unbroken), but then realized that what went in the box was a single piece of three-conductor wire, with black used for hot, white for switched, and ground not connected.
So... before I start digging the junction box out, what are my odds of finding neutral somewhere in the vicinity? More generally, I'm having a hard time imagining why someone would wire the ceiling light fixture and not have power and neutral come from the same place! So, before I get myself in trouble, how did they likely wire it?
Thanks in advance,