Nah, you just need a nice low supply impedance to see it. With a fault current of, say, 250,000A the difference between a circuit breaker and a fuse is extremely obvious (if, of course, you have one hell of a good CT). I've seen the aftermath of a dead short applied to such a system whose CB wasnt rated for that level of fault current (and vaporised). oops.
its a bit harder to see in a house, where the fault current is 1,000 -
6,000A (depending on supply impedance, wire size etc). But I'm sure you've seen many a blown fuse whose rupture current was well below that (eg every 20mm glass fuse in existence). usually characterised by a totally destroyed fuse.have a read of some Gould-Shawmut (bought by Ferraz IIRC) app notes, or maybe "Applying low-voltage fuses - classes & characteristics", H.W. Reichenstein, McGraw-Hill, ISBN 07-606577-4
Cheers Terry