The chemistry of electric fuse arcing

Manufacturers of high-breaking-capacity fuselinks seek more accurate models of fuse behaviour during the arc period of operation. These models will only be produced if the understanding of fuse arc phenomena is improved. Arcing produces elevated temperature and pressure within the plasma and hence a chemically active environment. Experiments were done on very fast acting fuses with silver elements to ascertain the significance of the chemical reactivity. The tests included calorimetry, ‘wet’ analysis of fuse fulgurite, electron spectroscopy for chemical analysis, and determination of gas produced. The conclusions were that no chemical change takes place during fuse arcing. Current limitation must arise, therefore, from physical processes.