.I had my main breaker fail recently in my 2021 Caracal for some reason, and when I went to replace it I noticed some things so I thought I would post the following as something to consider.
If your connections are like mine you will notice from one of the attached pictures that the big lug that comes off of the battery that attaches to the battery side of the breaker does not have a a lot of contact to the lug on the breaker. So I added the copper pieces that you see to compensate for that so there will never be any contact issues. Great part is you can do just what I did on the cheap. I took a 1/2″ copper pipe coupler, cut it in half, flattened it out with a hammer, and took tin snips to cut it to size. Then just drill the appropriate size holes.
I drilled a slightly larger hole for the bottom copper piece so it would rest on the base of the breaker lug. The top piece was a 1/4″ hole which was the size of the breaker post. As you can see the area of the 2 copper pieces covers most of the lug coming off of the battery to the breaker connection. Once I was done I then took everything apart and coated everything with die-electric grease.
On the other side of the breaker you can see that the connection lug from the engine was also a bit over sized. With this I just added stainless steel washers and die electric grease so there would be a much better contact. 
That breaker in the opening post has been mentioned over on BBC several times with respect to failure. Bass Cat explained that during supply shortage, the Blue Seas breakers they had been using were on back order 8 months at that time. That was the replacement. The Blue Seas is better quality. My Classic came with a 25 amp Blue Seas.
