A year ago I started remodeling an old room in our house to turn it into a study. Part of the deal was to rewire it for additional lighting in the ceiling for the various book cases and the double desks I was going to build in. I split the power for the single switch into two, so that I could have a separate feed for the lighting under the wall cabinets over the desks, and another for the ceiling lights. Power loading is fine, even if I were to use 75 watt bulbs. Installed a couple of dimmer switches, and after a few issues trying to get the wiring right I left it all as is once it had all tested correctly, with the wires still dangling down from the ceiling, because I got caught up in a couple of rehab projects elsewhere that needed priority. I didn't want to actually install the lighting at that point as they would have got in the way of the bookcase installation eventually.

A year on I've picked up the study project again, and while I was putting up the bookcases kept bobbing my head near the wiring for the lighting, so I decided to double check to make sure they weren't active, even though I had wire nuts over the bare ends - they were. Flicked the switches the other way, checked the black wires again with my tester - they were still active. Now I know I got it right when I did the job before because I remember testing it all out with all old light that I cut the plug off, stripped back the wires, and attached directly to the wires. Went and found the same light in my garage, attached it again, and sure enough, when I turned the light switch on and off, it worked - the light went on and off. Same when I took the light and attached it to the wiring for the desk lighting. Yet if I take the light off and test the wiring, doesn't matter if the light switches are in the on or off positions - the black wire for each of the two separate circuits remains active. How can this be?

I know I had issues with all of it a year ago, and maybe I went through all this back then and have just forgotten about it. All I know is that as things stand it all works, but I just want to be sure that there isn't something wrong that could cause issues down the track. Does it have something to do with the dimmer switches themselves - that vaguely seems to ring a bell with me.

Sorry for the long post - just wanted to be sure I spelled it all out clearly.

PS - Since I posted this I also ran another little test. Like I said, if I detach the wiring for the light and test the switches, the black remains active whether the switch is on or off. Out of curiosity, I attached the wiring for the light again, and found that it I tested the active wire with the circuit complete my tester shows that it goes on and off like it should. Why should making the circuit make the feed work one way, and another when it's not attached?