This is not necessarily the correct way to do things. Electrical wiring in a skoolie seems to be a subject of great debate. There are lots of ways to set up the electrical on a skoolie, some are good ideas, some are not. Here is how i do things in my bus.
Breaker boxes seem unecessarily costly, and I hate to spend money. I decided that i could make my skoolie just as safe, without the expense.
One 15 amp circuit is plenty to run all the 110 volt stuff in my bus. I simply run all the electricty (inverter, shore power, or generator) through a GFI. The GFI will trip much easier than a standard breaker, and they only cost about $7.00 at Home Depot.
Care must be taken when choosing the connections to ensure that all of the outlets "downstream" from the GFI are also protected.
Quis custodiet ipsos custodes (who will watch the watchmen?)