What is this?

[Richie]

Being a first time Thor owner I was puzzled when I saw this attached to the bottom of the battery box. The rubber boot covers what appears to be either a fusable link or a simple terminal block. Can anyone clear the mystery for me? What is it and what purpose does it serve? Removing the boot revealed a very corroded set of threaded studs that are in dire need of cleaning.

[JimOIB]

It is a breaker. On my coach it is 50 amp and a manual reset

[Richie]

OK. Sounds logical. I figured it had to be some sort of protective device. How is yours reset and what does it protect? Wires to mine look no bigger than 14-16 guage, rather light for a 50 amp circuit breaker. When the cover is removed all I see is what appears to be a metal link or fusable link. Perhaps mine is not resettable and needs replacement when blown. Will post a photo with boot removed. Too late tonight to crawl under it. Thanks for the quick reply.

[JimOIB]

The diagrams show it between the coach battery and the disconnect before the converter. It is connected with 6 gauge wire which can handle 50 amps. When tripped, there is an indicator button on the breaker that needs to be pushed in.

[Richie]

Thanks Jimbo, you have pointed me in the right direction. As you can see from the photos mine does not have any reset feature. It is a metal enclosure with no visible reset button or device. The terminal posts are labeled for battery and auxiliary. I confirmed the cable size using a known 12 gauge wire placed next to the red wires in question and they are definitely no larger than 12 gauge. Cannot tell where the cable harness terminates as it is in a bundle of wire armor at least 6-8 feet long all zipped tied to multiple bundles next to the battery box. First I need to remove the nuts and clean the connections. BTW the coach is a 2018 Quantum RS26.

[JimOIB]

Your breaker looks like a Sea Dog resettable breaker. On the battery end of the breaker you should see a small round spot that is the reset. It is pushed in now so you might not feel it. This link will show you it - http://sea-dog.com/groups/683-resett...ircuit-breaker

You’ll need the coach 12 volt layout and 110v diagrams from Thor to see how it is wired in. My diagram definitely shows a 50 amp breaker with 6 gauge wire...but who knows how it was really wired

[JimOIB]

Everything I said was a lie. I found the breaker for the disconnect relay before the converter with 6 gauge wires inside the coach near the disconnect. I crawled under my coach and it appears the breaker in the battery compartment is for the alternator to battery connection. I guess it protects the alternator in the event the coach batteries short.

[Richie]

Problem solved, sort of! Jimbo put me on the right track. Mine is not a Sea Dog resettable, but a Bussman auto reset breaker. Amperage unknown since all markings missing. Found both Sea Dog and Bussman on Amazon. Ordered 30 and 50 amp in hopes of finding true rating in next few days. Relocating it to a dry location. Case on old one is cracked and nut on stud is seized up from rust and corrosion due to exposure to the elements. Another example of “what were they thinking?”. Will try to trace cables back to source to determine purpose or may trying calling Thor for info.
Thanks Jimbo for your time and help!

[Richie]

Originally Posted by jimbo12

Everything I said was a lie. I found the breaker for the disconnect relay before the converter with 6 gauge wires inside the coach near the disconnect. I crawled under my coach and it appears the breaker in the battery compartment is for the alternator to battery connection. I guess it protects the alternator in the event the coach batteries short.

That would explain the large 6 gauge wire. Due to mine having the standard smaller gauge wire I’m thinking it could be the 12v source to activate the store/use relay. It could feed 12v to the store/use switch to activate the relay. Since it is auto reset if a short were to occur it would trip each time one attempted to switch to “use”. Just a theory for now!

[powerboatr]

just love how its right in the path of who knows what from the road.


one would think it would tucked away out of harms way.