Everyone should be no stranger to the digital multimeter, in addition to the measurement of basic parameters such as voltage, current, resistance, capacitance and transistor, it can also be further expanded by flexible use, so that its function can be further expanded to achieve the purpose of multi-purpose. But did you know that a digital multimeter can also be used to determine wire and cable breakpoints?

When the cable or cable internal fault occurs, due to the external insulation wrap, so that the exact location of the broken line is not easy to determine, with a digital multimeter can easily solve this problem.

Specific method: one end of the wire (cable) with a break point is connected to the fireline of 220V mains power, and the other end is suspended. Pull the digital multimeter to AC2V gear, start from the firewire access end of the wire (cable), hold the tip of the black watch pen with one hand, and move the red watch pen slowly along the insulation cover of the wire with the other hand. At this time, the voltage displayed on the display screen is about 0.445V(measured by DT890D meter). When the red pen moves to a certain place, the voltage displayed on the display suddenly drops to a few volts (about one-tenth of the original voltage), and about 15cm from the position forward (firewire access end) is where the wire (cable) break point is.

When using this method to check the shielded wire, if only the core wire is broken and the shielding layer is not broken, this method is powerless.

The broken core fault point has the following methods to detect: induction method can be used induction pen and digital multimeter; Suitable for cables without metal armor and steel tape shielding; Pay attention to prevent electric shock, the test and the end of the device when winding, etc.

Specific practices:

1, the conductor core of the cable suspended in the air, and ensure that it will not cause short circuit and electric shock accidents; At the same time, ensure that the cable is as far away from the grounding body (such as the ground and equipment) as possible.

2, select a sound insulation core in the cable, connect the 220VAC phase line (live line), no grounding line;

3, if the induction pen is used, the finger contacts the induction contact on the pen, and tests whether the pen is normal outside the insulation layer of the live body. If you use a digital multimeter, put the multimeter at 20 or 200mV, put a thin plastic insulating sleeve on the red watch pen, and hold the black watch pen with your hand; Test and read outside the insulation layer of the specified live body; Then move away from the charged body more distant position, and read; Compare the difference between two readings, usually with a higher reading on the charged body, such as 0.4mV, and a lower reading away from the charged body, such as 0.15mV; With this feature in mind, you can start testing.

4, close to the cable along the cable test, when it is found that the induction pen light darkens, or the reading of the multimeter significantly drops, the change is the breakpoint.

5, test completed, pay attention to discharge.

Qingdao Tianxing Cable Co., Ltd. focuses on the production of customized wire and cable manufacturers, main: fire wire and cable, power cable, control cable and other products, exported to more than 40 countries and regions around the world, the annual production capacity of 1 billion yuan. 6000 square meters of storage, standing hundreds of millions of inventory, order demand for rapid distribution and delivery, large prices more favorable. Hotline: 16678668098