Final update: just wanted to give an update and thank everyone for their input. All my troubles came from a silly connection error, which caused the fuse to blow when I turned the main breaker on. When I visually checked the fuse it looked perfect, which led to my puzzled questions. Turns out that I should have removed the fuse and checked continuity before continuing, which is what I did last night. After I replaced the fuse I rechecked all my connections, fixed the problem, then the circuit worked as expected and it was a simple job.