Originally Posted by grahamlthompson:
“Why do you think that only 3A and 13A fuses are now made ?
”
Sorry Graham but you're wrong on that, 5A fuses are widely available:
eg.
http://www.toolstation.com/shop/Elec.../sd2620/p84422
http://www.screwfix.com/p/5a-fuse-pack-of-10/78280
I've bought some myself recently.
Also, the purpose of the fuse as I understand it is to prevent the appliance being overloaded by a sustained over current and heating and catching fire as a result. The fuse acts as a current limiter and whilst it won't protect the equipment from being damaged by a sudden over current as it won't react quickly enough, it should protect it from being overloaded to the point of catching fire.
That's why its important to have the right value of fuse in the plug - so the appliance can draw its maximum rated current but if that is significantly exceeded, the fuse is there as a limiter to prevent that overheating occurring.
I would agree there are probably circumstances where technically the value in the plug is irrelevent, most notably where the manufacter fits an internal fuse on the power in socket in the appliance thereby limiting it there, and where the power lead's rating exceeds that of the fuse in the plug.