Six Judgment Methods of Cable Breakpoint

Here are some quick methods to determine the breakpoint of wires and cables

1. Digital multimeter method

First, connect one end of the cable with the breakpoint to the 220V live wire, and suspend the other end. Adjust the gear of the multimeter to the AC 2V voltage gear. Then, starting from the live wire access end of the faulty cable, one hand firmly holds the black probe, and the red probe slides slowly along the insulation layer of the faulty cable. The voltage value at the cable without breakpoint is about 0.445V. When the red probe moves to a certain place, the voltage displayed by the multimeter drops suddenly 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.

2. Induction pencil method

Firstly, it is ruled out that the cable around the breakpoint cable has power supply, and then the cable with breakpoint is connected to the live wire, and then the inductive pencil is used to move vertically to the cable slowly. When the AC signal of the inductive pencil disappears, it can be judged that the breakpoint is at the detection point, with an error of no more than 10cm at most.

3. Polyline method

For shorter cable test breakpoints, the bending method can be used to connect the two ends of the cable to the red and black probe ends 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.

4. Acupuncture discrimination

This method is to use the connection and disconnection of the cable to check the location of the cable breakpoint. Insert the steel needle into the breakpoint cable section by section, and then use a multimeter to measure the on-off condition in turn. The difference is where the breakpoint is. However, the party * * damaged the insulation layer, which could easily cause other problems in the later use of cables.

Methods of professional instrument detection

1. For the judgment of underground cable fault point, audio detector can be used to judge the fault point.

2. Cable fault telemeters can be used to judge the overall length of the cable and the short circuit and open circuit points.

3. 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.