Another priceless gem from yourself demonstrating your general cluelessness The fuse rating and therefore the plug rating in the case of a non rewireable plug is determined by the cable attached not the appliance it will be used with Where on earth did you dig that nonsense up from There are plenty of good examples around but medium to large switch mode power supplies are often supplied with nominally 3 Amp cable in a moulded on plug many with an IEC 60320 C7 type plug rated by that standard at 2 5 Amps According to you the plug should therefore be fitted with a 3 Amp fuse determined by the cable If you did so you would never get any but the smallest power supplies running You have to fit a 5 Amp fuse because the very large 40 Amp momentary inrush current lasts long enough that it will blow a 3 Amp fuse The cable and plug can retain their original ratings because the inrush current will not harm them The rating of the fuse is determined by much much more than the cable size alone Indeed the type of power supply that is built into a plug usually has no fuse at all 17 17