It's obvious that the available current wasn't enough to clear any protective device(s) OR that short wasn't as much of a short as you were led to believe. You will have to look at the time/current curves for the fuses to see when they should clear. One of my pet peeves is looking at a set of curves that doesn't show the time that the fuse should clear at 105%. I also just recently saw a set where several of the curves crossed.
