NF-608 electric tester pen Non-contact 100V-240V AC Voltage Detector Sensor Tester Pen Identifying hot and neutral conductors, and detecting the presence of ac voltage at outlets, switche Detect 50-1000 AC voltage Measurement category: Category 1v, 1000v per ul 61010 To find a break in a hot conductor,the wire breakage point is where the signal stops To find a break in a zero line, it needs connecting a load between the hot conductor and zero line,