A complete list of cable breakpoint determination methods
When there is a breakpoint failure in the cable or the inside of the cable, it is difficult to intuitively judge the definite position of the breakpoint due to the package of the external insulation skin.
Here are some methods to quickly judge the breakpoints of wires and cables: the method of non-damaging cables 1. Digital multimeter method. First, connect one end of the cable with breakpoints to 220V Live Wire, the other end makes it dangle.
Mobilize the multimeter gear to reach the AC 2V voltage gear.
Then, starting from the live line access end of the faulty cable, hold the black pen with one hand, and The Red Pen slides slowly along the insulation layer of the faulty cable. The voltage value at the cable without breakpoint is about 0. About 445 V.
When the red pen moves somewhere, the voltage value displayed by the multimeter plummets to 1/10 of the normal voltage, that is, 0. 04 V.
At this point, it can be basically concluded that the breakpoint is at this position forward (Live Wire access terminal)15cm.
If the shielding layer of the shielded wire is not damaged, then this method can not be used.
2. Inductive pencil method: firstly, eliminate the power supply of the cable around the breakpoint cable, then connect the breakpoint cable to the live wire, and then use the inductive pencil to move slowly perpendicular to the cable, when the AC signal of the induction pencil disappears, it can be judged that the breakpoint is at the detection point, and the error is no more than 10cm at most.
3. Broken line method, for the shorter cable test breakpoint, the bending method can be adopted, and the two ends of the cable are connected to the two ends of the red and black pen of the multimeter.
Bend back and forth from one end of the cable. If the multimeter is off at this time, the breakpoint is here. According to this method, it has been checked until the breakpoint.
There is a method of cable damage 4. Acupuncture discrimination method. This method is to use the on and off of the cable to check the breakpoint of the cable.
Insert the upper section of the breakpoint cable into the steel needle, and then use the multimeter to measure the on-off condition in turn. Different places are where the breakpoint is located.
However, this method will destroy the insulation layer and easily cause other problems in the later Cable use.
5. Professional instrument detection method. In addition, for the judgment of underground cable fault point, the fault point can be judged by audio detector.
For the judgment of cable length, short circuit and open circuit point, cable fault Telemeter can be used.
According to the actual situation, different methods are used to judge the breakpoint. The above methods can basically determine the breakpoint of the cable.