2nd 30A Service

Yes, functionally, my breakout is the same as the adapter you showed above. Mine is home made and I built it before I saw that Marinco made one.. It's 100% safe and it works. The purpose of the slide lockout it to be able to only have one 30A breaker on at any given time. It's impossible to turn both on at the same time. When the panels are combined, the outside plug for the second power cord is isolated because it's associated breaker is turned off. This is a standard practice and configuration in the marine industry and the panels are made to specifically do this. The only difference is that we are required to break both the hot and neutral leg where as NEC does't require it on a trailer. I changed this panel around so that only the hot on both legs are switched. That's the only difference. Everything is well protected, the 50A outlet is double breaker protected at the pedestal, the two 30A inputs at the panels are breaker protected, and then it goes to the standard branch circuit breakers. There's nothing "Rube Goldberg" about it.