I haven't tried it with lights but with doors, you can add a powered tag and they can be connected to electricity. It may work the same with lights.
Or, you can use a mod that is already created that let's you turn on and off any light in the game without connecting to power. This let's you use all of the lights in CM without needing to set them all up as powered. If you don't mind not needing electricity for them. I forget the name right now but it is something like POI Light Enabler and has, I think, 2-3 letters in front of the name. It isn't on this forum but was either on Nexus or 7DaysToDieMods. I use the mod and it works really well.