Fuses - Are there any voltage conversion for the break-off
Your calculation gives the power dissipated in the load. A fuse blows by the power dissipated in the fuse - not the load. The fuse resistance will be very low and the power to blow the fuse will be correspondingly low.


The current rating is that nominal value which will blow the fuse in a certain time.
The voltage rating is the maximum voltage that can be reliably interrupted without forming and sustaining an arc across the burnt-out fuse wire.




Figure 1. GDC fuse time vs current. Source: Cooper Industries.

Note in Figure 1 how the 1 A fuse can sustain about 1.8 A indefinitely (1). On the other hand for a 1 s trip time (2) the fault current would have to be 3 A (3).


  How about the resettable fuses (with button) ? Is this the same ? because they are voltage rated too.


They will have the same limitations. Find a datasheet and study it in the light of my Figure 1. If you take my approach you will learn the new words and practice pronouncing them then start to figure out what they mean from the context in the datasheet and further reading. Read, read, read. It's worked well for me.