The SE-100T is a ground-fault-relay test unit designed to test the current pickup level of ground-fault protection. The tester injects current through the window of installed ground-fault current transformers to verify the operation of ground-fault monitors and relays. It is used on substations, motor control centers (MCCs), central distribution panels, switchboards, and test benches to verify relay operation. The SE-100T tests the entire ground-fault circuit including current transformers, wiring, ground-fault relay and the operation of the interrupting device. It is recommended to test every relay and its current interrupting device annually.