I know it's generally a bad idea to put Romex (NM-B) cable inside of
conduit because of the increased heat build up. However, I'm curious how
big of a problem it would be for a short 3' section of conduit?

When we wired our house a couple of years ago, I installed a few runs of
1/2" pvc conduit from the panel down to our crawlspace in hopes of making
future upgrades easier. Now I want to run power out to a small shed using
8/3 wire. The 8/3 Romex just fits inside the 1/2" conduit and will work
great if that short section of conduit is acceptable.

The cable will run through our crawlspace to a junction box. From there
I'll use individual wires to run through 1" PVC conduit (already installed)
out to the shed.

Can I use the conduit, or do I need to resort to fishing cables through the
walls and floor?

What if I strip the outer cable insulation and feed the individual wires
through the conduit (with a cable clamp at the bottom of the conduit)?

Thanks,

Anthony