A fuse is a critical — albeit simple — part of many complex electrical systems. Its responsibility is to prevent potential catastrophic loss. Fuses are made of a metallic-type element which is housed in a ceramic or glass tube, with a sand or silica-based granule inside. These granules are needed for filling any gaps in the body of the fuse. They do this to keep the fuse’s integrity and assure proper functioning. The sand and elements are held within a precision-ground, vacuum-packed, ceramic barrel. This barrel is mechanically strong, resistant to heat and features a good insulator — a combination for a long-life expectancy.
This device is then placed inside of a circuit. 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 like pure copper, silver plated copper, or pure silver.
The element, during normal operation, will become warm. But the heat is pushed away into the fuse link, flowing away without causing harm. In the event of an overload, the rush of current will melt the solder to open the circuit, which should create a break in the chain.
When a short circuit occurs, this is the chain of events: the element melts, arcing occurs across the break, and the current is interrupted very rapidly.
Think about what the fuse endures and the responsibility it carries. There is an enormous amount of electrical energy, which it absorbs in a very short time. The entire electrical system counts on it to do so.
Many standard fuses contain silver elements, while some are made of elements with standard copper, silver-plated copper, aluminum, and alloys. Silver elements allow use at higher operating temperatures up to 428°F/220°C, compared with 266°F/130°C for a comparable silver-plated copper element. Specialized fuses exist with gold elements for some specialized applications, including high-precision electronic systems, aerospace, and military.
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.