DrewE wrote:
I'm guessing the breakers are different sizes, the little slide needing a smaller breaker (either due to smaller gauge wiring heading towards it--though that's not obvious--or per the slide mechanism maker's specifications). Having them both fed through the large breaker prevents overcorrect if both are operated simultaneously, though I assume there's also a fuse or breaker at the battery end of the incoming power feed wire.
And, I agree with ScottG, that this is a neat and clean installation.
This sounds correct- it makes sense, at least.