fuse

With that said, fuses are purely thermal devices. They are made to melt wire in the event of a known value of overload or greater (sorta). This is the "fusing" current rating of the wire used, which for copper (not fuse material as stated by Gerald or Ralph) is about 10 times the usable current if using for electrical conductors, if it has plastic insulation that you don't want to melt (Ampacity da da).

In selecting and using a fuse, all sorts of things play into the equation of heat. At least with a commercial fuse, there is some sort of standardization as to the real current that will make it blow since it is in a housing and the housing only fits certain types of holders and all that.

Don't know where you are headed. Maybe you want to talk about that.

Mark

The strand in a 7 strand wire is 8 sizes smaller than the total wire. So 28 would be made of 7 strands of #36. I'm thinking I remember #30 fuses at 15 amps, so 33 would fuse at 7.5 amps and 36 at 3.75 amps.

I don't remember that being in an amateur radio handbook since my first one in 1952.

Copper wire as fuses aren't as reliable as fuse wire because it takes so much greater temperature to melt copper. So fuses made with low temperature fuse alloys tend to be used a great deal more. With automotive fuses available for a few cents each in discount stores, its hard to take the time to figure out copper wire fuses. And events that heat the copper but don't melt it will cause it to oxidize and change size making it more sensitive.

Gerald J.