Coordination of Fused Low-Voltage Distribution Systems

The blowing of a fuse involves two distinct functions-that of melting the fusible element, and then extinguishing the arc that is formed. The development of the coordinated system, that is, one in which only the fuse closest to the fault will open, is obtained if the sum of the melting and arcing energy of the smaller fuse is less than the energy necessary to melt the larger fuse.