Switch cabinet, box type substation, bus cable bridge, etc. are the most important components of electrical equipment. Under the working conditions of high voltage and high current for a long time, its dynamic and static contacts, bus joints, cable joints, etc. are prone to surface oxidation corrosion, loosening of fastening bolts, aging of contacts and connections, etc. these problems will lead to increased contact resistance, temperature rise and electrical safety accidents. TOSC electric hot spot fluorescent optical fiber temperature on-line monitoring device uses advanced fluorescent optical fiber temperature sensor technology to provide dynamic, real-time, safe and accurate "hot spot" temperature information of equipment operation, prevent sudden safety accidents caused by equipment overheating, and realize the intelligent mode transformation of equipment from "regular maintenance" to "condition based maintenance".