rv hook up at home

Weldon wrote:
Not arguing the point but why is it wrong to bury romex even if it is in conduit. Trying to learn something here.

Because the code says so. :)
Romex (NM) cable is not suitable for use in wet locations, according to the NEC, because of the bare ground wire inside the sheath. The inside of any conduit is considered a wet location. UF cable is similar to NM cable, but is rated for in-ground and damp-area installation. In fact, UF stands for underground feeder. From the outside UF cable looks like NM-B cable, but the wires are embedded as a group in solid thermoplastic insulation (rather than individually encased in flexible thermoplastic).