Unexplained 12v connection

[airwalk]

Hey everyone, on my new trailer I have a large gauge wire going from the battery to a post on the frame behind, and then from that post another large gauge wire goes into a hole through the frame. This is a separate circuit from the normal wiring for the 12v distribution system inside the camper as far as I can tell.
Does anyone have any idea what this is for? I'm not having any issues, I would just like to know. Obviously it needs a slightly longer wire to the battery as well!

Thanks!

[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.
Happy Camping

[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?

[pman1088]

That is likely the wire from the charger/converter to the battery. If it is, it supplies your trailer with 12v power from the battery when not attached to shore power and charges your battery when attached to power if your charge/converter breaker is turned on from your power distribution center. The "shortstop" box it's wired to in the picture...mine from the factory was only a 20amp and would "pop" a few times when my charge/converter would attempt to supply the battery with a bulk charge cycle and then the converter would supply a lower voltage charge. I replaced mine with a 40amp to solve the issue.

Though the wire appears short, the shorter the better. If you check your distance and gauge on a voltage drop calculator your likely under wired from the factory and there is significant voltage drop.


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[airwalk]

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.
Happy Camping

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.

[mike837go]

Originally Posted by airwalk

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.

What to you mean "wired incorrectly"? Be very mindful that wiring color codes follow household standards more than automotive.

White is neutral for 120/240 AC. On RV's it is -12V.
Black and red are HOT for 120/240 AC. On RV's you'll often find black used for +12V.
Green or uninsulated is ground for 120/240 AC. You will find bare ground straps between the frame and the engine or metal body panels. Green could be anything (often left(or is it right?) trailer stop/turn).

Double and triple check where the wires are going before you disconnect them to clean up the rat's nest the factory gave you.

[Mustang65]

Originally Posted by mike837go

Double and triple check where the wires are going before you disconnect them to clean up the rat's nest the factory gave you.

Good points, and while your are at it, take a few minutes and tag the cables with their destination/purpose for future reference.

Don