I am wiring an off-grid cabin for 12 volt lighting (no inspector within 15 miles). The wire will be run inside the walls. What type of wire should I use? Just regular Romex with the appropriate guage, or low voltage 2 conductor (no ground wire), and maybe run it inside conduit in the wall to protect it from nails going through the interior cedar panelling? Do I also need to run a separate ground for the electrical boxes?