I know what you likely meant, fused matched to a wire gauge feed. A set of spare slots in the fuse panel.
But to be clear, never have an unfused wire, especially for automotive. The bus bar from the 350v battery better be fused (i.e. three separate 100A circuits for AWD). The 12V tap better be fused to match the wire gauge at least, and for each circuit it is feeding, with an upstream fuse to the panel to protect it. Even with electronics with switches, but they could be unfused if they have current limiting, thermal limiting and short circuit protection (ie automotive class VFET with integrated protection).