I received your photos via email
The large red wires are connected to a circuit breaker That feeds a strip of buss work. Note the copper colored studs.
The smaller green and red wires are connected to branch circuit breakers.
The studs on the bottom have a second nut that attaches the circuit breakers to a non-metallitc bracket.
The large red wire on the top stud could be a problem. It appears to be an after market installtion to feed something with large load. I would disconnect it and try to find out what it feeds. It may need a circuit breaker of it's own coming off the bottom stud.
You would need to take the back nuts loose to remove circuit breakers from the bracket. After removing the right hand circuit breaker, look closely on it for amperage. Disconnect power from batteries and from the shore power to be on the safe side.