A short circuit is a special case of fault current. If you left a wrench lying across two phases of a bus, that would be a short circuit. It's only one type of fault current (there are several).
If you connected the A phase supply to ground instead of to the A phase lug, then you’d have a bolted ground fault.
In either of these cases, the connection is solid. And it’s unlikely (but possible) that the breaker or fuse will open (clear the fault) in time to preven