What is the 10A fine-wire fuse in the Premium-Line surge protectors for? December 05, 2022 12:55 Updated It protects the built-in RF filter from overload. A defective fuse can be easily replaced. Related articles Is a surge protection device still functional after an overvoltage? Why is the internal thermal fuse not exchangeable? How are our RJ-45 jacks assigned for surge protection? What does it mean when the green indicator light is off on surge protection power strips? What does 4,500A / 15,000A / 30,000A etc. mean in the surge protection devices?