Something of a philosophy question here...
I've recently moved into a 100+ year-old house and, in addition to finding the usual decaying wiring (mostly BX), I have discovered all sorts of poorly done and potentially dangerous work (mis-wired receptacles, neutral-switched switches, grounded receptacles without grounds, etc, etc). I believe I can handle most of the fixes for these things, but I'd like to comply with the laws and get permits and have my work inspected.
The question is, in the opinion of the "old hands", where is the dividing line between work needing a full permit and a simple "repair"? Replacing a receptacle: sure, no need to pull a permit, but what if I replace a corroded 6-foot BX run with some fresh NM at the same time? I think there is a gradation there, but I don't have a feel for its parameters.
Also, I have some lingering uneasiness related to 3rd-hand stories of inspectors demanding whole houses be brought up to code, whenever any work is done which disturbs the "pre-existing" state of the wiring. While this sounds counter-productive (since this would disuade people from doing any work, when even a little could really enhance the safety of the wiring), it doesn't mean it doesn't happen. Or, maybe this is mostly paranoia on my part?
Anyhow... any thoughts appreciated.