A fuse is simply a carrier of electrical current which has a special function to interrupt the passage of current flow whenever there is an overcurrent in its path. An overcurrent could be a sustained overload, fault, or short circuit in the wiring, equipment, or electrical devices. These materials have an electrical rating and an overcurrent occurs when the current exceeds that rating. The link inside the fuse housing is made and designed of materials which are calibrated to open the circuit by melting whenever there is an overcurrent beyond its calibration settings to safely carry electrical current. Once the fuse link has opened the fuse has done its job in circuit protection. This fuse is commonly referred to as “blown” and will need to be replaced once the condition that caused the fuse to blow has been remedied or repaired.