A fusible link Wire is a type of electrical fuse that is constructed with a short piece of wire typically 4 American wire gauge sizes smaller than the wire that is being protected. For example, an AWG 16 (16 gauge) fusible link migHeat be used to protect AWG 12 (12 Guage) wiring. Electrical fusible links are common in high-current automotive applications. The wire in an electrical fusible link is encased in high-temperature fire-resistant insulation to reduce hazards when the wire melts.