Kit kat Fuse is a type of rewireable fuse that consists of a porcelain base, two conducting elements, and a fuse wire. The conducting elements are mounted on the porcelain base and the fuse wire is placed between them. When the current flowing through the fuse wire exceeds its rated value, the wire melts and breaks the circuit, protecting the electrical system from overcurrent. The name Kit Kat comes from the resemblance of the fuse base to the chocolate bar of the same name.