There are those that tell you the solid copper will vibrate and fail. There are those that tell you an extention cord will heat up and short out burning your trailer to the ground.
OMG what shall we do.......
My first build I used 12 -3 extention cord and have ran everything but a window shaker air conditioner on it. ( I run a seperate 10-3 cord direct to it) It was nice being able to drill a small 5/16 hole and thread it thru the 3/4 members where needed. I used the 1/2 depth carlon electrical boxes and standard duplex outlets.
I chose to use toggle switches for the ac because they were smaller and I could place a rotary switch in the same box for the dc switching.
OH by the way if you mix ac and dc in the same fixture you are doomed also.
When I built the barn I had a 2 1/4" wall cavity so it was easier to wire with 12 - 2 with ground standard copper
