A core unit for a leakage current detection and interruption device includes a control circuit board; a drive coil assembly coupled to the circuit board, including a coil holder frame and an input or output assembly connected thereto; and a magnetic movement assembly nested with the drive coil assembly, including a magnetic movement frame and the output or input assembly connected thereto. In response to relative movements between the drive coil assembly and the magnetic movement assembly away from or toward each other, the input and output assemblies are disconnected from or connected to each other, respectively. The core unit achieves reset function and trip function by the coordination of the drive coil assembly and magnetic movement assembly, effectively ensuring power connection and disconnection while reducing the number of components. This design reduces the size of the device and reduces assembly cost.