All TraceTek products monitor in a fully supervised 4-wire configuration. Current is flowing on all 4 conductors all of the time even when there is no leak event. The TraceTek control module cannot be "disconnected" from any sensor lead without recognizing the event as a continuity failure and this cannot be confused with a leak event. This is not necessarily true with 2-wire and 3-wire systems.
TraceTek leak detection systems are UL Listed under Process Management Equipment and Tested to Standard 864 (Fire Protective Signaling Systems). Fire Protective Signaling Systems require the use of fully supervised circuits.