Toroid: Detecting leakage currents at high amperages is more difficult and requires more sensitive equipment. In such areas and industrial applications, toroidal systems are preferred for leakage current protection. Toroidal current transformers measure incoming and outgoing currents to detect leakage currents. The toroid and other circuit equipment work together to trip when the detected leakage current exceeds a predetermined limit. In this way, both living beings and systems and devices are protected from vital and financial dangers. When installing Frer toroids, all active conductors should be symmetrically routed through the center of the core. While the phases and neutral pass through the toroid, the ground wire (PE) should not pass through the toroid, but outside of it. The diameter of the cable passing through the toroid should be equal to or less than half the inner diameter of the toroid. The cable passing through the toroid should be positioned straight enough to be at least twice the inner diameter of the toroid. The connection between the toroid and the leakage current relay should be as short as possible and kept away from other power cables.