Feeo Electric Tells You Why Are Some Fuses Filled With Sand?
Current limiting fuses contain a granular filler, usually high purity quartz sand of a defined grain size and packaging density. The specific grain size distribution provides room to expand for the vapours and gases produced by the arc and offers a large surface for efficient cooling. The filler does melt under the influence of high arc temperatures, absorbing an enormous amount of energy and extinguishing the arc well before current zero. Fused quartz and metal form a non-conductive fulgurite body that prevents re-striking of the arc.