Abstract: The fusible element of a single-element, dual-function, electric fuse is disposed within a passage within a housing of inorganic ceramic material which has a high thermal conductivity; and the major portion of that fusible element is displaced radially from the axis of that passage to be in intimate heat-transferring relation with one side of that passage. Two of the "weak spots" of that fusible element are in close heat-transferring relation with the terminals of that electric fuse; and a portion of that fusible element which is intermediate those two weak spots is in intimate heat-transferring relation with the opposite side of that passage. The resulting transference of heat from that fusible element to that passage enables those two weak spots to continuously carry the rated current of that fusible element even though those two weak spots have very small cross sections, and hence are able to provide desirable current-interrupting action.

Abstract: A current-limiting, single-element, dual-function, electric fuse has a fusible element with at least one "weak spot" of very small cross section; and the temperature of that weak spot will exceed eighty percent of the melting temperature of the material of that fusible element when that electric fuse operates at its maximum continuous current carrying capacity. An appreciable amount of the heat, which the weak spot generates in response to a low but potentially-harmful overload, will be conducted to the inner surface of the housing for the electric fuse by the arc-quenching filler; and a substantial percent of that conducted heat will pass to, and be radiated by, the exposed outer surface of that housing.