Yea I was talking about variant 2, thanks for explaining. so it had to be less then 6, because 6v is the most the wire can carry?
A. 1 A - Would not serve the purpose as the appliance normally uses a current of 3 A, the fuse would be useless if it melts before the appliance can be switched on normally.
B. 3 A - Again there is no point at introducing a fuse if the appliance normally uses a current of 3 A, the fuse would be useless if it melts before the appliance can be switched on normally.
C. 5 A - When operating at normal, the current would rise to 4 A at maximum, we don't want a fuse with terminating current at 4 A or below. The cable to the appliance is designed for currents up to 6 A, hence 6 A is teh maximum that it can carries, nor do we want that.
D. 13 A - The cable to the appliance is designed for currents up to 6 A. A current that is larger than 6 A would damage the cable, we want a fuse that would automatically melts before the cable is in peril of damaging.