Type IFC relays are used for the protection of industrial and utility power systems against either phase or ground overcurrent. They are single-phase, non-directional, current sensitive AC devices. The basic operating mechanism (the time unit) produces one of several available operating characteristics with operating time inversely related to operating current to permit coordination with other protective devices. It consists of a magnetic-core operating coil, an induction disk, damping magnet, and a mechanical target. The IFC relay may also include a hinged-armature instantaneous overcurrent unit with its own target.