Hi everyone,
I have a new house and the builder left an empty 2" PVC conduit from the basement to the attic for future electrical expansion. It provides a nice straight unobstructed path. I'm planning to install some new lights and am trying to figure out the best way to make use of this conduit.
From what I've read, running NM or AC inside a PVC conduit is a no-no because of heat build-up. Given a PVC conduit, the consensus seems to be that you pull separate THHN stranded wires through it. I'm fine with that, but of course there are runs on either side of the conduit (to the panel on one side, and the load on the other side) and I'm not sure how to handle this.
I was actually thinking about putting in a 50A sub-panel in the attic so I only have to worry about this once. So the plan would be something like:
1. NM from the main panel to a j-box near the bottom of the conduit
2. Transition to the conduit run - how?
3. Run 3x6ga THHN (plus ground) through the conduit
4. Transition from the conduit run - how?
5. Connect to another j-box near the top of the conduit
6. Run NM from there to the sub-panel
This leaves the question of the transitions to/from the conduit run. Do I just reduce the PVC from 2" down to 3/4" (plenty big enough for 4 wires) and use a standard PVC j-box?
Or is there a better way to do this entire thing? Opinions seem to be split on whether NM through PVC is a code violation or simply not recommended... in my case, I'm only using the PVC because it provides a clear cable path. If I'm only doing one run, perhaps a single 6/3 NM through a 2" conduit is really not that big a deal?
Any advice appreciated.
I have a new house and the builder left an empty 2" PVC conduit from the basement to the attic for future electrical expansion. It provides a nice straight unobstructed path. I'm planning to install some new lights and am trying to figure out the best way to make use of this conduit.
From what I've read, running NM or AC inside a PVC conduit is a no-no because of heat build-up. Given a PVC conduit, the consensus seems to be that you pull separate THHN stranded wires through it. I'm fine with that, but of course there are runs on either side of the conduit (to the panel on one side, and the load on the other side) and I'm not sure how to handle this.
I was actually thinking about putting in a 50A sub-panel in the attic so I only have to worry about this once. So the plan would be something like:
1. NM from the main panel to a j-box near the bottom of the conduit
2. Transition to the conduit run - how?
3. Run 3x6ga THHN (plus ground) through the conduit
4. Transition from the conduit run - how?
5. Connect to another j-box near the top of the conduit
6. Run NM from there to the sub-panel
This leaves the question of the transitions to/from the conduit run. Do I just reduce the PVC from 2" down to 3/4" (plenty big enough for 4 wires) and use a standard PVC j-box?
Or is there a better way to do this entire thing? Opinions seem to be split on whether NM through PVC is a code violation or simply not recommended... in my case, I'm only using the PVC because it provides a clear cable path. If I'm only doing one run, perhaps a single 6/3 NM through a 2" conduit is really not that big a deal?
Any advice appreciated.