Rockwell 855PC-B20ME522

Current rating is the maximum current that a fuse will carry for an indefinite period without too much deterioration of the fuse element.

IP (or "Ingress Protection") ratings are defined in international standard EN 6529 (British BS EN 6529:1992, European IEC 659:1989). They are?used to define levels of sealing effectiveness of electrical enclosures against intrusion from foreign bodies?(tools, dirt etc) and moisture.