Sometimes It's Good to Be the Weakest Link
A fuse is a critical albeit simple part of many complex electrical systems which is responsible for preventing potential catastrophic loss. A fuse is made of a metallic type element which is housed in a ceramic or glass tube and has a sand or silica based granule inside. These granules are needed to fill any gaps in the body of the fuse to keep its integrity and assure proper functioning. The sand and elements are held within a precision-ground, vacuum packed ceramic barrel. This is mechanically strong, resistant to heat and a good insulator, for a long life expectancy.
This device is then placed inside of a circuit and its job is to disrupt the current of electricity should an overload or short circuit occur.
As important as the fuse is, the element is the vital part of the fuse. This is generally made from high conductivity materials such as pure copper, silver plated copper or pure silver. Plain wire can be used but only up to a 12A rating.
The element, during normal operation, will become warm but the heat is pushed away into the fuse link and flows away without causing harm. In the event of an overload the rush of current will melt the solder and open the circuit which should create a break in the chain.
When a short circuit occurs this is the chain of events: the element will melt - arcing occurs across the break - current is interrupted very rapidly
Think about what the fuse has to endure and the responsibility it carries. There is an enormous amount of electrical energy which must be absorbed in a very short time because in truth, the entire electrical system is counting on it.
Recently the fuse industry introduced fuses with silver elements instead of the standard copper or silver-plated copper elements. The reason for the change is that silver elements allow use at higher operating temperatures, up to 220°C compared with 130°C for a comparable silver-plated copper element.
This may make all the difference in proper functioning and is important in high temperature environments. Systems which rely on fuses with temperature needs have started to take advantage of the benefits of fuses with silver elements to achieve performance characteristics that were not possible with conventional fuse links.
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