This is a low voltage GCS, it incorporates a 24 volt A.C. relay combined with an impedance matching transformer which make it possible for the relay to "see" small changes of resistance in the pilot/ground circuit. The ground check system utilizes a ratio of 10:1 on the transformer, normally, so that a change of 1 ohm appears as 100 ohms to the relay. It has a manual reset and tripped indication. The manual reset feature gives an indication as to what circuit tripped the breaker with the indicating light. This light must be reset manually before operation can resume. It has additional ability to adjust ground loop resistance up to 4.5 ohms from front panel.