Battery Disconect Switch

Disagree all you want [emoticon] ... fact is, resettable CBs are accepted as standard in the industry for good reason and obviously meet regulatory requirements, whether you agree or not. [emoticon] Fuses blow permanently and once they blow are a PITA because the only way to get the circuit to work again is to replace the fuse entirely at the risk that it too may blow if there's a fault still remaining in the circuit, whereas the resettable CB simply won't allow power through until the fault is corrected. Adding an additional fuse to a circuit that is already wired with a resettable CB serves no purpose.

Thanks, I will (just as yourself at the beginning of this thread) :B.

Again, this is all obfuscating the original question by the OP, "How do I install a disconnect switch to my batteries?" but I'll engage.

If there is a shorting event in the circuit between the circuit breaker and the battery, there is no circuit protection. The wire and any devices connected to it, may suffer a catastrophic failure. If the short maintains continuity, with 200AH of batteries, the cable and the switch will melt/burn. If a circuit breaker or catastrophic fuse is installed at the battery, circuit protection is provided for the whole circuit, including the trailer.