The lower the gauge number, the thicker the wire (i.e. 10 ga. is thicker than 16 ga.) A fusible link is a special section of low tension cable installed by an OEM and designed to open a circuit when subjected to extreme current overload. Its purpose is to minimize wiring system damage when such an overload accidentally occurs in those circuits protected by the fusible link. A short circuit causes the fusible link to act as an element in a "slow-blow" fuse. A fusible link is not intended to be used in place of a fuse but only where a fuse cannot be economically employed. Our fusible line wire meets the requirements of SEJ-156 and the insulation has the characteristics as listed for EAE, SE J-1128Type SXL. The vehicle manufacturer should be consulted about questions on fusible link length and size. General practice has been for a fusible link to be 4 gauges smaller than the circuit wire. Example: if the circuit wire is 12 gauge, use a 16 gauge fusible link. Final determination should be based on O.E.M.application. Note: Extreme care should be taken to always replace a fusible link with the same gauge and length as installed by the manufacturer.