Actually, if I understand you right, you don't need to "fix" the wiring to either one. You can fish wire inside the finished ceiling without attaching it to anything.

really?!? you are saying that wire can just kind of "lay" on top of a ceiling when running parallel with joists? that makes life easy. i figured one could not put it where it could be inadvertently damaged by someone cutting through (eg for a new light fixture)

If you were going to attach it, and if code doesn't care, I'd suggest you attach it to the joists above. I say this because i think it's more likely that you or someone else would want to raise or replace the ceiling (or even a section of it--especially in the basement, where ceilings can be sort of low), and the romex might be in the way. But it would be less likely that anyone will mess with the floor.

I also suggest that if laying the romex on top of the framing is acceptable to code, that you should provide plenty of slack--again, so that someone could come along later and raise the ceiling by 6 inches without having to redo the wiring.

I have a place where my licensed electrician suggests that we run wire over the kitchen cabinets, inside the soffit. He suggests this because then we don't have to deal with trying to work inside that space to attach it--cabinets are a pain to take down, space is small and too high to be easy to work in, etc.

Because there is a very strong likelihood that someone might take *out* the soffit I put in, and because this is wiring that involves the circuit-breaker panel, they REALLY arent going to want to re-address the whole thing. I'm going to ask him to be sure there's enough slack that someone later could shift that flexible conduit all the way to the back, or up against the ceiling, etc., at a later date without having to rewire.

It's like a haircut: you can always cut it shorter pretty easily (if you can get to a junction box on either end easily, you can shorten it there). "Cutting it longer" is impossible, and w/ electrical, you can't just splice it any old where you'd like to, since you have to have a junction box at the splice.

you can fish in the wires like Ron said.
Code doesn't address "what if's". You can never out guess what someone is going to do later on if you sell the house.

talley_sue - excellent points. my curiosity stems from wanting to install the wire with as few ceiling cuts as possible. as it stands, the can light cuts make wonderful access points, although i don't know if i'll be able to get to the joists above.

i am glad to know - although a confirmation would help - that it is basically my choice how I affix the wire and if i even affix it at all.

while i'm at it - if you're running wire parallel with joists and need to go perpendicular, what kind of bend is used? in data wiring, 90 degree turns are a big no-no but i am not sure if it is different with the thicker and more rigid electrical wiring.

also - is it considered a best practice to run perfectly perpendicular when traversing the joists or is a diagonal run typical?

You can never out guess what someone is going to do later on if you sell the house.

I agree--but I like to build in flexibility.

Just to be clear, every use of the word 'wire' in this thread should be replaced with the word 'cable' or 'NM-B', as NONE of the practices discussed to this point would be legal or compliant with individual conductors, aka 'wires', sans conduit/raceway.

That said, I personally would get as much of this cable run properly affixed (w/ listed staples) well ABOVE the drop ceiling, yet also well BELOW the fixed floor above... a happy mid-point if you will, regardless of what the NEC allows, or simply doesn't address. As mentioned above, the dangers from future "DIY fiddling" (yours or others) is just too obvious to ignore.

"That said, I personally would get as much of this cable run properly affixed (w/ listed staples)..."

The reason for the exception of not requiring fished cables to be fastened in place is to limit the damage to walls and ceilings when fishing cables.

If you are going to cut enough holes to fasten the cable in place, why bother even fishing?

Just chop holes every four feet, pull the cable in, and fasten it.

thanks again everyone. with the can lights in the ceiling, i should be able to just fasten the wire above the lights, which are about every three feet or so. i'm going to fasten on the very bottom of the floor joist, which is still above the ceiling framing. nothing should be able to touch it from above or below.

and unlike previous owners, i'm going to document everything i do and pass it on should we ever sell the house (though for now i plan to die here - and i'm only 30!)

Just make sure there are no junction boxes with out access.

fixizin - thanks for the kind words. yesterday i found a junction where one of the runs was armored cable going off to who knows where. i don't have any receptacles or lights (that i know of) that use armored cable. i have found some abandoned BX in the basement ceiling, but this one i found yesterday is hot. i am assuming they just used it in the then unfinished basement (perhaps required in unfinished / crawl spaces at the time) and i simply have an abandoned light socket above the finished basement ceiling.

but the point is that I don't know! i wish someone had documented what the heck was going on. but now i'll have to trace the cable and figure out if it is safe and what to do.

and don't even get me started on our service panel. i'm finding multiple circuits that control ostensibly nothing.

regarding the digital / paper dilemma. i have a wife that prints and files everything. so i'll trust her to file it. meanwhile, i will keep a digital copy on my computer, which i try to back up periodically.