HI GUYS

I have a couple of questions dealing with fuses and their design...
Is it true that automotive fuses are designed to withstand start up current spikes high above their amperage rating-without blowing the fuse?
Also, if a worn out component operates at or just under max amperage,can it cause it's fuse, the fuse box and joining wires to melt and burn without actually blowing the fuse and opening the circuit?

I really appreciate your time and help

Q1: Yes

Q2: No. The primary cause of the failure that you describe is poor connections at the fuse. This causes excessive heat which does all sorts of bad things destryoing the fuseholder and melting the insulation of the attached wires.