Originally Posted by Northern Jay
That little box with the large Guage wire is a 30 amp circuit breaker. It is there to cut power to the trailer from the battery in the event of a short circuit.
Originally Posted by DanNJanice
On my trailer the wire you are showing is the main battery wire for the whole DC system. The "studs" are a self-resetting circuit breaker.
What other wires do you have running from the battery to the trailer?
Thanks for the help, guys. My last trailer didn't have a circuit breaker near the battery (or at all), just the 30 amp fuse. Now that I look closer I see it's a circuit breaker. There is also a 30amp fuse, so this was throwing me off as it's for the electric tongue jack (although wired incorrectly...).
I haven't studied all the wiring yet, but it appears what I thought was the main wiring is the brakes wiring.
I have to clean up all the wiring near the battery, it looks like it was wired Monday morning after an awesome long weekend! It's a mess, but easily cleaned up.