Cartridge Fuses are the ideal fuse for the protection of high current circuits because of their ability to provide an increased time delay and low voltage drop. This cartridge fuse has a rating of 40 Amps and 32 Volts. Fuses are a necessary component in an electrical circuit because they offer an essential protection by acting as the weakest point in a circuit. When a current is too strong, the fused element inside a fuse will heat up and break so that the current can no longer complete the circuit.