[April1]

Originally Posted by Bill S

Interesting that the 20A fuse (54) blew while the 5A (1) did not in a previous incident.

Fuses are usually coordinated. This means that the nearest fuse to the fault location should clear the fault, minimally affecting other circuits and other functions.

Fuses blow based on their i*2t characteristics and are mainly affected by Load current, rate of rise of current, operating voltage, ac or dc current, operating temperature. Same fuse may work differently in different networks, so it is not just a amperage rating of the fuse. But you are right if some one puts 5A and 20 A fuses in series ( though no one would do that), 5 A fuse is likely to blow first.