I've been delinquent in watching this thread! It took me a moment to realize these were MY pics!
The install is a commercial building. The A/C is only half the picture; the other is the furnace (not yet installed, hence the stub-out.) The t-stat wire needs to go there, because it is the furnace blower that circulates the air past the evaporator coil - which is mounted in the same ductwork the furnace uses.
This is 'kosher' since the t-stat wire simply tells the furnace controls to turn on the blower; it doesn't actually power the blower.
You see two wires because there are to be two units; one to serve the upstairs and one to serve the downstairs. Both heating units are located in the same (second floor) mechanical room.
A little bragging is in order. This job was my first 'design/build' effort. Details were sketchy, and the manner of construction unforgiving. Still, I was able to guess well enough that, in the end, I only needed to relocate two receptacles- and I was able to 'cheat' a bit on those.
