Thinking about using 2" PVC conduit attach to the top of circuit breaker panel. The conduit would run up the side of the wall, (note: panel is surface mounted), then 90 over to the center of the room, where the opposite end would terminate inside a large j-box. Something like a 6x6x4. Yes I know thhn individual conductors would work better. But it's money thing. Have the romex cable left over, and just want to be sure this nothing the NEC code that would prohibit this practice. And how exactly do you measure the dia. of 12-3 romex? Thanks to all who show an interest and reply.