RV Load Disconnect & Fuse

[Guy Planner]

Hello; I am in the process of converting my 5^th wheel camper to solar (2021 GrandDesign Reflection 240RL). I will be installing a new RV Load Disconnect and fuse, closer to the batteries. But I am unsure of the fuse type and size (amperage). I attach my wiring diagram.
Any help is appreciated.
Guy

[howson]

Hello; I am in the process of converting my 5^th wheel camper to solar (2021 GrandDesign Reflection 240RL). I will be installing a new RV Load Disconnect and fuse, closer to the batteries. But I am unsure of the fuse type and size (amperage). I attach my wiring diagram.
Any help is appreciated.
Guy

Did you forget to attach the drawing?

[Guy Planner]

https://1drv.ms/b/s!AoukeVoHOqD1gcUf...jRHuA?e=3dVx82
oops, here it is

[Jkwilson]

Look at the smallest wire connected to the circuit and size the breaker/fuse to protect that. Looks like 6AWG feeding the rig’s panel, but you also have some 10AWG connected to that circuit as well. Though you have breakers on those wires, they can only protect the wire past the breaker from the power source, so a pinched wire between the battery and breaker could result in a 10AWG wire carrying the load you meant for the 6.

[Guy Planner]

But is that not the case for any busbar ? My MPPT controller and my DC to DC charger are "upstream" from the busbar (& batteries). The 10AWG cables for each of those devices should only carry power from MPPT to batteries or DC DC charger to batteries. Am I missing something ? (PS. I really do appreciate your feedback).

[ncitro]

But is that not the case for any busbar ? My MPPT controller and my DC to DC charger are "upstream" from the busbar (& batteries). The 10AWG cables for each of those devices should only carry power from MPPT to batteries or DC DC charger to batteries. Am I missing something ? (PS. I really do appreciate your feedback).

You fuse to protect the wire not the load, so if you have 10AWG wire connected to a busbar fed with a 6AWG then you would want to fuse the 10AWG at an appropriate amount (30A) to protect it in the case it gets pinched and shorted.

[Jkwilson]

Sometimes you need to upsize wire to make a layout work with multiple sources of power. Anytime you transition to smaller wire, each one needs an appropriate circuit protection device.