Fusing Current

Fusing Current refers at which the fuse is designed to melt and disconnect the circuit.  Wiring rules specify the fusing current for different circuits.  It is also known as minimum fusing current.  


Fusing Factor
The Fusing Factor is the ratio of the rated current and the fusing current

Therefore,
Fusing Current = Fusing Factor x Rated Current

The fusing current will always be more than the rated current.  Thus, the fusing factor will always be greater than one.