Shore power at pedestal is 250/50 amp split phase. This runs to a Y cable splitting it into to 120/30 shore power supply’s. Those cable come into the boat and connect to 2 30amp elci breakers. 1 for each supply. I am attempting to recombine the neutrals after the breakers and connect the supply into a Multiplus II 2x120v. A soon as the multiplus runs through its start-up process it pops the breakers. Why does this setup not work?