What are the origins of the fuse?

Answer 1

I have never seen the answer in any textbook, or heard it in any classes or seminars, so I'm going to have to give my opinion. First, let's discuss what a fuse does, and why, and that will give us an idea of how. The purpose of a fuse is to PROTECT the wire[s] in an electrical circuit from overheating as a result of too much electrical current [Amperes, commonly refered to as Amps] flowing through the wire[s]. If the "overcurrent" and the subsequent overheating is allowed to continue, it is possible for the wire to get hot enough to destroy the insulation on the wire, and to IGNITE adjacent combustible materials, causing a fire. Obviously, that is not a good thing, and must be avoided. The size [amount of current it will carry without blowing out] of a fuse to be used in a circuit is determined by the size [amount of current it will safely carry] of the wire which it will be protecting. A fuse is nothing more than a small, short section of wire [refered to as a "link"] inserted into an electrical circuit, such that the link [inside the fuse] is "SMALLER" than the wire it is protecting, and thus cannot carry as much current as the wire. Then, IF electrical devices [too many, or too large] on the circuit "draw" more current [Amps] than the fuse is designed to carry, the link inside the fuse overheats until it reaches its melting point, at which time it melts through, and "opens up," cutting off the flow of electricity through the circuit. The process I just described usually happens in only a fraction of a second, and is literally a miniature "explosion" [of the link], hence the phrase, "blown" fuse. On the other hand, if the overload is only very slightly above the rating of the fuse, the failure may not be explosive, and that is why some "blown" fuses do not show visual signs of heat, fire, and smoke inside the fuse. The fusible link is enclosed inside the fuse body, thus containing the hot, molten particles and heat, preventing initiation of a fire. Also, household [110 volts AC, and 220 volts AC] fuses are mounted inside a metal fuse box, providing additional containment and safety. Due to the smaller voltage [therefore less energy involved], automotive fuses do not require the metal enclosure, as the fuse body is sufficient to contain the arc resulting from failure ["blowing"] of the fuse. Although I don't know who developed the first fuse, or when it was developed, it is obvious that [early in the electrical "era"] someone observed the phenomenon of wire heating caused by overloading, and realized that a "weaker" fusible link in a circuit would protect a wire from the effects of overloading. This I suspect is "HOW" fuses began.