Originally Posted by tabetha

The reason is some fuses are rated continuous, like older glass fuses, some like Blade fuses are rated as blow ratings.
The rating of wire is always continuous, a 17 amp cable wille asily supply temporarily 25 amps top blow fuse.
Best way of working out amperage cable need is V/I X R, or watts /volts = amps.
18 AWG is 0.823 mm/2, 1.624 circular mm.
Additionaly thinwal cable carries around 35% more current than std insulation at the same thickness.
tabetha