Question on SMB wiring

[Belize]

I have now moved from suspension on to the electrical system in my quest to “fix” system problems with my 2006 E350 SMB. I removed the back seat to reveal a rats nest of wiring (see image). I started mapping what is there and immediately was confused. I am not an electrician, but do have some experience wiring homes.

I traced the shore power line to the panel board with two breakers. The 110v line is attached to the first 30amp breaker, not a breaker bus bar as I am use to. Then the 110 line exits the box from a second 15amp breaker to the GFI socket. Why have the 110v line enter the system through a 30amp circuit breaker and exit through a 15amp breaker. Shouldn’t the 110v line attached to the breaker bus bar, then a single circuit breaker protects the single line going to the GFI plug? (See image). Am I being clear and am I missing something here?

[Scalf77]

You have a 30 amp main circuit and a 15 amp branch circuit correct? While this would be small for a house wall panel, you need to expand your idea of bus bars. The power comes in through the 30 amp plug, which is wired to a neutral bus bar and ground bus bar, The input goes to the 30 amp breaker which does have it's own bus bar, the 15 amp circuit picks up that bus bar and distributes it to the GFI plug and then i suspect on the the power supply plug. If you wanted to add an additional 15 amp circuit you could easily? While your build does not have a heavy AC load they are using parts that could be used for larger systems.

-greg

[Belize]

I am wondering if there is a reason that the 30amp breaker and the 15amp breaker are wired in series? Seems like the 30amp is useless as the 15amp will blow first...or am I missing something? Do other SMB owners have this same setup?

[Belize]

Greg, after sleeping on it, I now understand what you meant. Basically, the 30amp breaker is a main breaker. The 15 amp is the GFI and there are still 3 more slots that could be expanded, all controlled by the main 30amp breaker. Guess I am so use to a separate home main breaker that I indeed needed to expand my view. Thanks!