Conduit and wire questions in home

[Indiana]

I would like to install a pvc pipe from my basement to my attic. I have a 2-story house and the run is about 25-30ft. I have a straight shot from point to point. I would like to have 6 circuits total in it when I am done. I have some 12-2 NM-B w/g wire I would like to put in it. The conduit is just for my ease of use. Is this wire OK for use in conduit? What size/type of conduit should I use? Like I said, this will just go from the ceiling of my basement to the floor of the attic. No turns or bends.

Thanks,
Indiana

[SSN596]

You are not allowed to put sheathed cable in conduit, except in some small (short) exceptions. Your situation would not be allowed.

[HayZee518]

As stated as in above, romex is not permitted in pvc runs. THHN, THWN is permitted. Code says that 0-4 use the total amperage available - after 4 conductors the amperage rating is reduced by 80% so apply the ratings for anything beyond four conductors - this includes the neutral etc.
Kinda stinks but this is the code!

[Rewired]

Check with your code what they specify but up here its not so much the number of conductors, but the number of "current carrying" conductors.. Grounds do not count as a current carrying conductor.
Neutrals of "multi-wire" branch circuits do not count. (Multi-wire being where one neutral is shared between two hot wires from opposite phases of your panel, the neutral carrys only the "unbalance" current. If the neutral is part of your basic 2-wire circuit, then you MUST count it because it carries full current...
Now I KNOW I am gonna get my butt raked over the coals for this one BUT... IF its ok by the code in your area, you could run those circuits as "multi-wire" up to the attic and save yourself having to run a separate neutral for each, not to mention having to de-rate all your conductors even more.. ( you would only have to de-rate for "6" current conductors instead of "12") The only catch is you must make sure that you never open a neutral or have any possible way of having the neutral on a multi-wire circuit open up... You could have high voltages appear across some of your loads...

[LazyPup]

rather than run all those circuits why not consider running a main and putting a branch panel on the upper floor?