Welcome to the world of trailer wiring. Brings a whole new meaning to trailer trash. The trailer manufacturers has a "loop hole". Trailers are built in a "factory" therefore they fall under a different set of rules. If the manufacturing process to includes the wiring is under an engineering control environment, then the person doing the wiring as well as the materials do not have to meet local building codes. This is true with modular homes, buildings, and RV's as well. It is no differnt then some of the equipment we work on. Lets say we are required to bring #10 wires in for power and we land them on a lugs that have #14 on the load side. We are not resposible for the equipments wiring just connecting the power correctly. This is typical on motors.