Overload Protection Mechanism Of Drop-out Fuses

The heat generated in power distribution lines under overload or short-circuit conditions can carbonize the conductor insulation, ultimately leading to a fire. How drop out fuse set prevents wire overheating and even fires depends on the thermal response characteristics and breaking capacity of its fuse element.

drop out fuse unit The internal fuse tube is made of tin-copper alloy or pure silver, with a melting point set between 232℃ and 960℃. When the line current exceeds 1.3 times the rated value, the fuse temperature rises according to the I²R law, reaching the melting temperature within 2 hours to achieve breaking. When the short-circuit current reaches more than 10 times the rated value, the fuse element vaporizes and breaks within 0.01-0.1 seconds, interrupting the fault current much faster than the thermal breakdown process of the conductor insulation. The quartz sand particles filling the fuse tube absorb the arc energy, cooling and solidifying the metal vapor to prevent arc reignition and secondary faults.