Series connected fuses and fusible components operate by the fusing of one or more of their elements, which opens the connected circuit by breaking the current when it exceeds a given value for a sufficient time. Fuses and fusible components are intended to prevent potential hazards caused by overcurrents. The two main equipment application areas are AC mains ports and information and communications technology (ICT) ports where AC mains incursion is possible. This Recommendation considers fuse and fusible component types, the electrical stress levels pre- and post-operation and gives circuit examples.