Electrical Engineering - 2A Fuse and 5A Fuse

The actual element for a 2A fuse will have a smaller cross-sectional area, whether throughout the length of the element or in reduced sections of the element. Either the 2A or 5A element could be enclosed in an outer shell (fuse body) of the same dimensions. Thus the outer shell doesn't tell much other than the general range of the fuse element within.

Thank you Mr.Tornado.. Suppose if we use copper as a material for fuse, what will be the dimension of internal wire for 2A and 5A fuse?

In this case

1) melting point of copper to be considered.

2) heat developed across the fuse by joules law of heating to be considered..

Is there any expression to be linked with the above considerations.

The fuse element will have a resistance R that depends on the resistivity of the material and the dimensions of the smallest sections of the element. The heating will be I²R, but some of the heat will dissipate into the medium surrounding the element (air, sand, whatever). I don't think copper is commonly used; maybe silver or some other alloy. This is actually a rather complex design, based partly on calculations and partly on empirical testing. I don't know if we have any fuse designers on board, but if kvsridhar sees this, he can probably add some more detail.

Thanks Tornado.

This being a vast subject, i feel that the OP can benefit by downloading and studying this document from Cooper Bussmann... http://www1.cooperbussmann.com/pdf/092bf8cb-767c-4bac-8b87-8e0838fc3585.pdf

A British Standard 1362 fuse rated at 2A is identical to one rated at 5A apart from the printing on the case and the diameter of the fuse wire inside it.

Formulae for the constructional differences are somewhat esoteric, given that the value of them is usually less than £0.25GBP retail.

There is not enough difference in filament size between a 2 amp fuse and a 5 Amp fuse to have any constructional difference. That difference is in the application of the fuse. Some of which the ease of manufacturing comes to play. Use to be all just about all auto took round AGC fuses. Now their flat. Some of the constructional differences are do to how the fuse reacts to the load. You have fast acting, slow blow, time delayed these have more to due with case sizes then the filament. It's only when the filament size is need to handle and protect a load. That the case will change.