LIMITATIONS OF VOLTAGE INDICATORS AND TEST PORTALS Impedance Sensor leads not connected Line voltage, unprotected leads Test Portal Test Portal Front of Door Front of Door Voltage Indicator Voltage Indicator Poor workmanship or installation failures can lead to a zero voltage indication when the conductor is energized. Both Test Portal and Voltage Indicator leads bring hazardous voltage to the door. No voltage at test point when fuse is open Test Portal FUSE FUSE Front of Door Voltage Indicator If the fuse is open, zero voltage will be indicated when the conductor is energized. C A N A D I A N A U TO M AT I O N VOLUME 3, ISSUE 2 38