Do you know how to determine the cable break point?

　　Digital multimeter method:

　　First, connect one end of the cable with a breakpoint to the 220V live wire, and make the other end hang in the air. Adjust the gear of the multimeter to the AC 2V voltage. Then, from the live wire access end of the faulty cable, hold the black lead tightly with one hand, and the red lead slowly slides along the insulation layer of the faulty cable. The voltage at the cable without break point is about 0.445V. When the red probe moves to a certain place, the voltage value displayed by the multimeter drops to 1/10 of the normal voltage, i.e. 0.04V. At this time, it can be basically concluded that the breakpoint is 15cm forward of this position (the access end of the live wire).

　　If the shielding layer of the shielded wire is not damaged, this method cannot be used.

　　Induction pencil method:

　　First, eliminate the power supply of the cable around the breakpoint cable, then connect the cable with the breakpoint to the live wire, and then use the induction pen to move slowly perpendicular to the cable. When the AC signal of the induction pen disappears, you can judge that the breakpoint is at the detection point, and the error is not more than 10cm.

　　Polyline method:

　　For short cable test breakpoints, the method of bending can be used. Connect both ends of the cable to the red and black pen of the multimeter. Bend back and forth from one end of the cable. If the multimeter is on and off at this time, the breakpoint is here. Follow this method until the breakpoint.

　　Method of damaging cable

　　Acupuncture discrimination:

　　This method is to use the connection and disconnection of the cable to check the cable break point. Insert the steel needle on the breakpoint cable section by section, and then use a multimeter to measure the on-off condition in turn. The different points are the breakpoints. However, this method will damage the insulation layer, which is easy to cause other problems in the later use of cables.

　　Professional instrument detection method

　　In addition, the fault point of underground cable can be judged by audio detector.

　　The cable fault telemeter can be used to judge the cable length, short circuit and open circuit point.

　　Different methods are used to determine the location of the breakpoint according to the actual situation. The above methods can basically determine the location of the cable breakpoint.