Do you know the measurement methods to accurately determine the break point of a wire or cable?
01
Multimeter Detection Method
First, connect one end of the entire non-conductive cable to the live wire of the strong current, and leave the other end empty. Set the multimeter to the AC2V gear. Starting from the connected end of the cable, while pinching the tip of the black probe, slowly move the red probe along the insulation of the wire. At this time, the voltage value displayed on the screen is approximately 0.445V.
When the red probe moves to a certain point, the voltage displayed on the screen suddenly drops to about 0.0x volts, which is approximately one-tenth of the original voltage. The break point is located about 15cm forward from this position (towards the live wire connection end).
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02
Inductive Test Pen Detection Method
An inductive test pen is a device with an electronic screen that can detect voltage and continuity. First, ensure that the cables around the break point are not powered. Then connect the cable with the break point to the live wire. Hold the test pen perpendicular to the wire, press and hold the "Inductive Break Point Test" button, and slowly move forward along the wire. When the AC signal detected by the test pen suddenly disappears, the break point can be determined at that detection point, with an error of no more than 10cm.
Note: The cables around the break point must not be powered. Of course, this method is not universal; it works well for short cables, but the longer the cable, the less effective it becomes.
03
Using an Audio Tone Generator
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An audio tone generator is an instrument that uses single-frequency or multi-frequency signals to test line continuity and identify line faults. It can directly locate wires while connected to any switch, router, or PC terminal. When tracing cable lines, there is no need to strip the outer sheath; it is simple, fast, and can determine the location of line break points.
04
Cable Fault Tester
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It is a comprehensive cable fault detection instrument. It can test high-resistance flashover faults, high and low resistance grounding, short circuits, cable breaks, poor contact, and other faults. If equipped with an acoustic pinpointing device, it can accurately determine the precise location of the fault point. It is particularly suitable for testing various types of power cables and communication cables of different voltage levels.
05
Bending 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 200Ω resistance range. Bend the wire back and forth at the most likely break points (such as frequent bending points). If the multimeter shows intermittent continuity, that is the break point. If it cannot be determined, start bending from one end of the cable until the break point is found. This method is suitable for shorter cables.
06
Needle Puncture Detection Method
This method is a destructive detection method. Insert steel needles at intervals into the broken cable, and use a multimeter to measure the continuity between the needles and the cable end to determine the break point.
Under normal circumstances, it is not recommended because it damages the insulation layer, which can easily cause other problems during later cable use, especially in humid environments. This method uses the cable's continuity to identify the break point.
07
Pull and Tug Detection Method
This is also a destructive detection method and is rarely used in practice. Use pliers to pull and tug the broken wire at the cable end. If the break point is near the cable end, the insulation will easily tear. This method is used for cables with break points near the cable end.
To measure the break point of a wire or cable, you can refer to these methods. When conditions permit, it is better to use instruments and equipment to improve work efficiency.
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The cable fault tester is a comprehensive cable fault detection instrument. It can test high-resistance flashover faults, high and low resistance grounding, short circuits, cable breaks, poor contact, and other faults. It is suitable for measuring low resistance, short circuits, open circuit breaks, high-resistance leakage, and high-resistance flashover faults in various cross-sections and dielectric power cables (such as high-frequency coaxial cables, local telephone cables, street light cables, and buried wires). It can automatically generate test reports.
