The NIS64x2 is a cost effective, re-settable fuse which can greatly enhance the reliability of a hard drive or other circuit from both catastrophic and shutdown failures. It is designed to buffer the load device from excessive input voltage which can damage sensitive circuits and to protect the input side circuitry from reverse currents. It includes an over-voltage clamp circuit that limits the output voltage during transients but does not shut the unit down, thereby allowing the load circuit to continue its operation.