I cannot vouch for whether you are a bad boy and violate any building codes, BUT why not run PVP pipe outside? I'm not sure of your situation, but you could bury it 2 feet underground and be set for the most part. Shielding of cables is really only useful if your wire is going to be exposed to alot of magnetic interference(like your main power line to your house is going to be right next to your LAN cable). Indoors though, I'm not sure why you'd need PVC. I hope you aren't having to protect your cables inside your house more than outside!