Electrical – Installing window a/c unit

Chances are pretty good that the red wire is just extra (or the black wire). The two most common types of wire for lighting and outlets come in 2 and 3 wire varieties, so sometimes you have an extra wire. Try to hook up just the white and black (green to ground), and see if it works. If not, swap the black for red.

Of course if you have a voltage tester, you can check the white/black and white/red pairs for voltage before hooking up the light.

There's a small chance that one of the red or black wires has constant voltage and the other is switched, so use a voltage detector and make sure all the power is off before splicing anything.

Here are my notes:

GFCI protection is required for all receptacles in unfinished basements (210.8(A)(5)).

Any habitable room in a basement may require an emergency escape route (see this answer for more detail), so check with the local building department. Note that "emergency escape", is slightly different than "egress" even though the terms are sometimes used interchangeably.

So the catch-22 here is. If you call it habitable space, you don't need GFCI protection, but you need an emergency escape route. If you call it an unfinished basement, you need GFCI, but not an emergency escape route.

As of NEC 2011 (I think), a grounded (neutral) is required at switch locations (404.2(C)). So only cap the neutral at the switch, and connect it at the junction.

The labeling is helpful if you are doing work in the future, but may not be helpful to another person that doesn't understand your labeling system.