What is the 10A miniature fuse in the Premium-Line surge protective devices for? March 05, 2024 09:42 Updated It protects the built-in HF filter from overloading. A defective fuse can be replaced. Related articles Is a surge protection device still functional after an overvoltage? Why is the internal thermal fuse not replaceable? What does it mean when the control indicator on surge protection socket strips is off? How does a surge protection device work? What does 13,500A / 19,500A / 60,000A etc. mean for surge protection devices?