I'm not sure where you're located, but here in California, mobile or manufactured homes are regulated & inspected by the CA Dept of Housing and Urban Development (HUD).
I helped organize a group that fixed up a mobile home for a retiring minister. The home had aluminum wiring, so we rewired from underneath the trailer in romex. We assumed the NEC would apply.
Wrong! The inspector made us rewire the underside in conduit, as the CA code required the wiring be protected against damage should the home be moved. What a pain! The original permit was $399 and the re-inspect was $196 (almost $600 for a 1200 ft home)
Be careful!