I do honestly wonder, Mr Ha, whether you actual want someone to try and explain a point you are genuinely interested in, or are just trying to pick arguments for the hell of it. Yes, fuse wire will have greater resistance than the supply cable because it is thinner, (the resistance of a wire is in inverse proportion to its cross-sectional area). But a 3A fuse wire, for example, still has a very, very low resistance. If it had a significant resistance, it would cause a significant voltage drop across it, which would affect whatever appliance it was supplying. Yes, the resistance of a wire will also increase as it gets hotter. No contest. It's all pretty academic, tho' - I'm just trying to explain why greater resistance doesn't create greater 'heat', which is what you seem to think. Did you follow my point about the electric element; if you halve it's length, you will halve (lower) its resistance, and this will double the current flowing through it, and it will glow twice as brightly. So, reducing the resistance is increasing the element temp. I'm trying - and am about to give up - to explain why your understanding of this: "Now you KNOW that isn't correct. The filament doesn't glow BECAUSE it is a smaller gauge wire. It glows because it is a different metal and therefore has a different resistance. For example, tungsten." is misguided. "Otherwise, all our 3A and 13A fuses in our plugs would be glowing." Indeed they do - when they begin to reach their rated current.