To alert utility-line workers of overcurrent conditions on such aerial devices as insulated ladders and truck booms, the Chance Sentinel sounds an alarm if leakage current reaches a pre-set level. The leakage setting adjusts from 1 to 1,000 microamperes in resolution increments of 0.1 microamp. The audible warning eliminates the need to watch the actual current level, continuously displayed on the Chance Sentinel’s digital LCD screen.

The alarm sounds immediately upon overcurrent and continues until the condition is corrected. To also trigger a truck horn or other external alarm, a jack on the instrument panel accepts a standard 1/4″ two-conductor phone plug. A test terminal on the panel permits a simple continuity check of the monitor leads prior to each operation.