Abstract: A fillerless electric fuse having a tubular casing with open ends is provided with a fusible element in the form of an extremely fine wire extending from one of the open ends to the other. The casing is provided with a pair of annular sections of reduced diameter at opposite ends thereof which receive a pair of metal contact rings having an outside diameter substantially the same as the outside diameter of the fuse casing. The fusible element extends through each of the open ends of the casing and is welded into electrically conductive relationship with the axially outwardly facing surfaces of the respective metal contact rings. End terminals are press fitted over each of the metal contact rings and are permanently secured to the fuse casing. Means are provided inside the fuse to establish an impermeable barrier of insulating material within the fuse casing around the fusible element and between the end caps.

Abstract: A holder for an electric fuse is provided with a Hall-effect sensor arrangement which is integrally mounted in the fuse holder in close proximity to the current path through the holder. The Hall-effect sensor provides an output voltage responsive to the magnetic field resulting from the flow of current along the current path. The output from the Hall sensor is then processed to provide an indication of whether current is flowing through the fuse holder.