David Farber wrote:

How large a fuse would have to be in
the circuit to allow the traces to burn up?
The problem is, except for very special energy-limiting fuses, the fust does
NOT limit the current before it blows. It allows whatever current the unit
will draw for some amount of time before blowing. So, it is possible for
even a 1A fuse to allow fairly thick circuit traces to burn through when the
device has a dead short. It would not be unusual for a 1 A fuse to allow
maybe 100 A in a dead short situation, for a few milliseconds.

Jon