GFCI (Ground Fault Circuit Interrupter)
GFCI is a switch device that can leak-proof, safety accident prevention.
Operation principle: there are 2 winding on core, one is input current winding, another is output current winding. Input current equated output current when no leakage, and secondary leakage flux is zero, no electric potential on 3rd winding. Otherwise it will have voltage on 3rd winding, the switch will shutup.
Being as a special way of existance, the important feature of GFCI is that has function of judgement & detection. GFCI has function that break or connect circuit same as breaker, also can judge & detect leakage on circuit. If have a leakage in circuit, GFCI can enable its detect function and disconnet the components in circuit or connected. In additional, GFCI can collocate with thermal relay or fuse, the structural & functional will get imporoved. This device is widely used in the world.