There's a reason the manufacturers use fuse links instead of big fuses. If they're needed, there's a major short somewhere which will require at least a little wiring harness repair. As long as there's a "weak link" somewhere in the system to protect the rest of the circuit, the closer to the battery it is, the better. Having a fuse at, or near the alternator really isn't necessary.
Fuses don't do anything to protect individual parts- - - -they simply prevent wiring harness fires if something shorts out. Always fuse to protect the wire. 5-7 amp for 18 gauge, 10 for 16 Ga., 15 for 14 Ga., etc.
If you really want to add a fuse at or near the alternator, check with a shop that sells window-rattling sound systems. They have huge wires and big fuse holders for wiring subwoofer amplifiers that should carry alternator current with no problems.
Jerry
