Explain Wire Size and Fusing?

Question:

I currently have five circuits which are connected with a 14AWG wire from the battery (cigarette plug, propane, etc.) and a DC panel which is connected by a 12AWG wire from the battery switch. PYS recommends replacing both small wires with a large feed and distributing properly behind the DC panel. If I understand correctly, replacing the small wires with a large feed and distributing them properly is currently not a safety hazard as the wires are now fused at the battery or switch?

Answer:

Since the two wires are now properly fused, the issue is certainly less critical. As a matter of practice, one should NOT be constantly overloading a circuit and always depending on the fuse to prevent a fire. The fuse should act as device of last resort in the case of a very unusual circumstance.

Considering the following points:

1)      The boat is not actively being used at the moment

2)      An inverter CANNOT be run on the DC cigarette outlet

3)      DC loads should be kept to a minimum, i.e. sequentially turned on

I would say that this recommendation can wait.