How To Determine Where The Wire And Cable Break Is?

In actual engineering maintenance and repair, the biggest fear for maintenance personnel is encountering a broken wire or cable in the middle and not being able to find where the break point is. Although during the actual maintenance of our weak current engineering, we may directly try to replace or re lay cables when encountering cable problems, today we are discussing what technical methods can be used to detect cable breakpoints!
When there is a fault of a broken medium inside the cable, the exact location cannot be seen without insulation on the outside, including strong and weak electricity. The usual approach to finding the break point is to conduct a segmented investigation.
For example, if there is a blockage in the middle of a cable, measurements can be taken from both ends and three points in the middle. If one side is blocked, the midpoint can be taken for measurement. This way, the breakpoint position can be quickly found by narrowing down the range through troubleshooting.
So, in general, what are the measurement methods for accurately measuring wire and cable breakpoints?
01 Multimeter Testing Method
Firstly, connect one end of the entire cable that is not connected to a strong live wire, and leave the other end empty. Turn the multimeter to AC2V mode, start from the cable connection end, while gripping the black pen tip, slowly move the red pen along the insulation of the wire. At this time, the voltage value displayed on the screen is about 0.445V.
When the red probe moves to a certain point, the voltage displayed on the screen suddenly drops to just over 0.0 volts, which is about one tenth of the original voltage. The breakpoint is located about 15cm forward (at the live wire connection end) from that position.
02 Inductive electric pen detection method
Inductive test pen is a device with an electronic screen that can detect voltage and on-off status. Firstly, eliminate the possibility of power supply around the cable with a breakpoint. Then, connect the cable with a breakpoint to the live wire and place the probe perpendicular to the wire. Press and hold the "Inductive breakpoint test" button and slowly move forward on the wire. When the AC signal detected by the test probe suddenly disappears, it can be determined that the breakpoint is at the detection point with an error of no more than 10cm.
It should be noted that the cables around the breakpoint wires cannot have power supply. Additionally, it should be noted that this method is not omnipotent. Short cables have a significant effect, while longer cables have a worse effect.
03 Use audio detector
An audio detector is an instrument that uses single or complex frequency signals to test the continuity of a circuit and identify faults in the circuit. Can directly find cables when connected to any switch, router, or PC terminal. When tracking cable lines, there is no need to peel off the outer layer of the line, which is simple, fast, and can identify the location of the line break.
04 Cable Fault Tester
It is a comprehensive cable fault detection instrument. It can test high resistance flashover faults, high and low resistance grounding, short circuits, cable breakage, poor contact and other faults of cables. If equipped with an acoustic fixed-point instrument, it can accurately determine the precise location of the fault point. Specially suitable for testing power cables and communication cables of various models and voltage levels.
05 Line detection method
Connect one end of the broken wire to the black probe of the multimeter and the other end to the red probe. Set the multimeter to the resistance range of 200 Ω. Bend back and forth at the most likely point of breakage (such as frequently bent points). When the multimeter displays intermittent on and off, this is the breakpoint. If it cannot be determined yet, it is necessary to start bending from one end of the cable until the breakpoint is found. This method is applicable to shorter cables.
06 Acupuncture detection method
This method belongs to the category of damaged detection methods. Steel needles are inserted into the broken cable in sections, and a multimeter is used to measure the continuity of the steel needles from the cable end to determine the cable break point.
Under normal circumstances, it is not recommended to use it as it can damage the insulation layer and easily cause other problems during later cable use, especially in environments with high humidity. This method uses the continuity of the cable to investigate the location of the cable break.
07 Pulling Wire Testing Method
This is also a damaged detection method that is generally not used in practice, but it is also a method listed together. Use pliers to pull the broken wire at the cable end. If the break is near the cable end, the insulation skin is easily pulled off. This method is used for cables with breakpoints near the cable ends.
To measure wire and cable breaks, you can refer to several methods introduced today. If conditions permit, it is better to use instruments and equipment to improve work efficiency.