So you folks know...
The towed side breaker is 40 amps This suggests the UTB may draw as much as 30 when operating. the TOW side breaker (Motor home) is 20 amps per the instructions and as I recall the breaker on my coach is a 40.
The tie line is what 14ga.. or perhaps even smaller since it's stranded and I can't eyeball those as well as I can solid conductor. that's a bit much for 14ga wire. Plus the ground lead (which is smaller still) also has to carry the tail/ brake light current.
Home is where I park it!