T&T: 30 amp service vs. 50 amp service

[bob england]

It seems like that is what most people are assuming, that two thirties 
equals a sixty. But that's not how it works. It's the size of the breaker at 
the service panel, and the wiring to that point that determines service 
size.  It wouldn't matter if you had ten 30 amp services hooked to your 
boat, it would still be a thirty amp service, because that is what each 
individual circuit is rated for. If you connected a 30 amp 240 volt circuit 
to a transformer and dropped the voltage coming out to 120, you could pull 
60 amps (theoretically) on it without overloading the service breakers, even 
though they are thirties, then it would be cumulative, otherwise it is not. 
As concerns the big 50A cable, mine is very old and stiff, and after pricing 
a replacement I decided I like the pair of 30's better (sour grapes, ya 
know).