Methods for Identifying Breakpoints in Electrical Wires and Cables Using a Digital Multimeter
When there is a wire breakage fault in the cable or inside the cable, the exact location of the wire breakage is difficult to determine due to the wrapping of the external insulation skin. A digital multimeter can easily solve this problem. Specific method: Connect one end of the broken wire (cable) to the live wire of 220V mains power, and suspend the other end. Pull the digital multimeter to AC2V position, start from the live wire connection end of the wire (cable), hold the tip of the black probe with one hand, and slowly move the red probe along the insulation of the wire with the other hand. At this time, the voltage value displayed on the screen is about 0.445V (measured by the DT890D meter). When the red probe moves to a certain point, the voltage displayed on the screen suddenly drops to just over 0.0 volts (about one tenth of the original voltage). About 15cm forward from that position (the live wire connection end) is the breakpoint of the wire (cable).
When using this method to check shielded wires, if only the core wire is broken and the shielding layer is not broken, then this method is powerless.
Overview of Digital Multimeter
