Pulling wire to attic

I am installing ceiling fans in the bedrooms, which have no ceiling fixtures at all. I thought I would simply tap the entry switch for the switched outlets in the bedrooms, but the switches get a spur line only. I think all the outlets are already too packed to tap one of them. They all have a switched and an unswitched receptacle, so get a lot of connections. All other circuits up there look well loaded already.

I plan to pull new wire. I usually pull 12 guage to minimize resistive losses. I see no easy place to pull it from basement to attic. This is a 2 floor house with basement and attic. For some reason, the previous owner pulled new heat pump tubing to the attic from the basement, and left the old, which happens to be on an outside wall, whereas the new tubing is on an interior wall. (I have not asked them, but why would one do this? It is cut off at the entry into the attic, and into the basement.) The holes in the basement subflooring at the new tubing are huge (2"), and would accommodate wire, and I could probably dangle a chain all the way down. The old heat pump tubing is still there, in that exterior wall, too. The insulated tubing is too small (1/4"), but the uninsulated tubing appears to be 1/2". It looks like it could serve as a conduit to the attic. If outside buried conduit can be metal, can this copper tubing be code-approved conduit inside the house? I imagine I should not pull wire up beside the new heat pump tubing, but let me know if that defies national code.

No, soft copper tubing is not an acceptable material for conduit.
Remove the old refridge lines and pull MC cable.

Thanks. It looks like I cannot pull the tubing. The heat pump control wire was attached to the tubing with cable ties where it is exposed, and I suspect it was tied together all the way through the walls. That control wire is still used, so I cannot afford to pull the tubing and break the wire. I would like to remove the tubing and use the hole, but it appears too risky. A 12-2 NM will easily slide through the copper tubing. What is wrong with that?

The issue is that there is no precedence for using soft copper tubing as conduit. Imagine the cost of an installation.
I know it's tempting as hell to just pull NM up that tube but, code only tells us what approved materials are for conduit/raceways and soft copper tubing is not one of them. In addition, I don't believe you can run romex inside conduit.
Your probably correct on the fact that the old lines are secured all the way up and removal just isn't going to happen.
The only option I see is pulling MC.

I pushed the electrician's snake through the 1/2" tubing from the attic. I removed the wire from the attic heat pump to give 15' of slack. I then pulled the tubing into the basement over the snake. As each cable tie that held the control wire to the insulated tubing emerged in the basement, I cut the cable tie and then pulled the control wires back up as far as the new slack allowed. When I finished pulling the tubing into the basement, I was able to pull the control wire back up without ever losing it into the wall, so rethreading it through the wall was not needed. Now I have only the snake and the control were from the attic to the basement. Since the control wire will still be in the same hole/channel as a new power line, does this need conduit to meet code? I assume I can slide conduit up over the snake since the hole in the sole plate and top plate is 2", and I expect it to be the same in the middle.

Excellent work. I misread your previous post and was of the impression that the old refrigerant lines were stapled down to the studs. Good call. The control wires are low voltage 24VAC and do not require any type of conduit. Now for the extra bonus, take that old copper tubing to the scrap yard and they'll give you cash for it to help defray the cost of some MC cable.

Hello EdLank:
Just a passing thought that can be taken or left. I used a piece of PVC conduit in the corner of a closet to run a romex wire into the attic so it could pass over to another space. I used 1 1/2" conduit and may run some more wires through it as needed.
I'm not in a contest to see who is the top dog and I don't have a copy of the National Electrical Code, but it works for me.
Glenn

I tried pushing 1.25" conduit up the wall but found it missed the hole in a fire block (I think) about 5' up the wall, and instead kept going up beside the hole. When it did that, the electrician's snake was pulled down from the attic as I advanced the conduit. I cut an automotive funnel as a nosecone on the leading end of the conduit to get it through the holes. With help and a lot of struggling, I was able to pull a 10' piece up using the snake from the attic, while someone tilted and redirected it from the basement. I got all 10' up the wall, so it was past the top plate/sole plate between the two floors, so I felt I was past the hard part. With that piece up, I took a break before adding the second piece. When I returned, the first piece had dropped back to the floor. I thought there was plenty of friction to keep it there, so never would have thought it would fall back down. For hours I tried to get it back up, and even used a new funnel as a new nosecone. No luck. I cut my losses and simply pulled 2 pieces of NM12-2 up the wall. It works, but is not as elegant as I had anticipated. Sigh.

My understanding:
You actually can use NMB in conduit, as long as the conduit is sized big enough to meet code - IE the fill capacity

I used a pull rope to pull NMB to my 2nd floor
For phone, cable & CAT5 runs I stuffed (2) 10' sticks of conduit in to make it easier. I had a tough time getting it past the brick work on the fireplace, but they are in