[scottz]

Originally Posted by BB_TX

Yeah, I agree they should. But even if they are wired to handle 80 amps, the potential issue is with your trailer wiring and power cord. That wire is sized for 50 amps. And even though there are two hot legs of 50 amps each there is only one neutral wire. But due to the nature of how split phase 50 amps works, the neutral wire will never carry more than 50 amps. And normally much less. Split phase means the two hots always have neutral current flowing in opposite directions. So self canceling on the single neutral wire. If, for example, hot 1 was carrying 40 amps and hot 2 was carrying 30 amps, the neutral wire would only be carrying 10 amps. The 10 amps being the difference between the two. Pretty easy to see how that works with an electrical schematic but a little harder to clearly put it into words.

If the two 30 amp outlets were on the same phase, then both hots would always have neutral current flowing in the same direction and the neutral current would be the total of the two. For example, if both hots were carrying 25 amps the neutral would be carrying 50 amps. So with 30 amp outlets it would be possible to exceed the 50 amp wire sizing.

It's nice to have experts to think about this stuff. Showing an oscilloscope on the two legs, in-phase then out-of-phase, might make it clear.