Are you sure you didn't have both your pigtail and your switch leg landed on the tab connected hot screws and didn't notice it. It happens to everyone now and then.
It seems the only way the light would stay on regardless on any other previous miswiring that may have been present based on the fact the switch was controlling the light before you started.
If that were the case the "two legs out" could be explained by a crossed power out and switch leg, the power out going to something that either never got used or terminates in a box either in a crawlspace or a box buried in the wall that was never found while setting finish. Either way it wouldn't have been noticed that it was miswired (or perhaps abandoned, like a lead for an exhaust fan that was removed or never installed).
I would first confirm power in and switch leg out so as to positively ID which is the mystery cable and disconnect it from the ckt. Then do a check for ANYTHING not working. I look everywhere, in cabinets and shelves and of course behind stuff. If during this check you find any blanked off boxes I would look in them too. Don't forget the smoke detectors (I had that one once). If you can't find anything the only thing left do do is start tracing it. In crawl spaces or with a decent signal tracer. Sometimes both is what it takes to find a mystery wire.
And of course if your not comfortable with this hire an EC.
I believe it is still within 6' of a laundry tub or wet bar that requires GFI but it wouldn't hurt to install one.
And of course I could be totally wrong, good luck.
Last edited by ChicoC10; 08/05/09 01:02 PM.
