Fuse

—A strip of fusible metal, often consisting of lead with a small percentage of tin, introduced into an electric circuit as a protection against exce ive current. When the temperature exceeds a certain limit, the fuse “blows” and opens the circuit. Fuses should be placed wherever the size of wire changes or wherever there is a branch of smaller size wire connected, unle the next fuse on the main or larger wire is small enough to protect the branch or small wire, but more lights may be added on the large wire, making it nece ary to put in a larger. Experiments have shown that for large fuses, a multiple fuse is more sensitive than a single one. A one hundred ampere fuse may be made by taking four wires of twenty-five amperes capacity. A fuse block may be overloaded, not because the metal of the terminals is not of suffcient cro -section to carry the current, but because of insufficient area of, or loose contact of, fuse, or wires, and this heating is very frequently the cause of fuses melting. £