it doesn't really answer your question, but....
there is no such thing as an instant fuse either buddy
it does take time to burn through....
I use circuit breakers all the time for projects, I've got one in my john risch power filter for instance...
and I use a 30ms ELCB (Earth Leakage Circuit Breaker) for safety purposes, so when operating on 220 volt, 50 Hz power (as it is here in Singapore) the most I can get jolted by is a little over half a Hz of electricity before the thing trips and I'm safe. In effect, I would not feel a thing if indeed I was to get zapped because there would be no "zap", no short circuit at all, just a clicking button letting me know that there was an earth leak in the system somewhere.
