Test Leads For Multimeter | Explain in detail the necessary skills of electricians and use multimeter to detect circuits and equipment
1 judge phase line and neutral line
On low-voltage distribution lines, especially the indoor wiring of buildings, dark wires are often required to be laid through pipes for the sake of indoor beauty and durability. In the process of laying, it is sometimes necessary to find which is the phase line and which is the neutral line. Using a multimeter, you can easily judge the phase line and neutral line (you can scan QR code to learn).
(1) Contact measurement
① Judge with pointer multimeter
As shown in Figure 20-1, place the multimeter in the AC voltage "250V" or "500V" gear, wrap the black probe wire for several times, hold it tightly with your hand (do not touch the metal part of the probe), and touch the two sockets (or the exposed parts of the two wires) on the power socket with the tip of the red probe in turn. One time when the probe deflects to the right, the red probe touches the phase line and the other time is the neutral line.
For example, using dt9808 digital multimeter, turn the change-over switch to the "2V" AC voltage (ACV) gear, and judge which of the two plastic wires of the energized line is the phase line.
The specific method is as follows: first separate the measured ends of the two wires by 2 ~ 3cm, and then contact the outer skin of the other wire with the tip of the red watch pen. The display value is 0.846v. Therefore, it can be judged that the conductor with the measured voltage of 0.846v is the phase line, and the conductor with the lower measured voltage is the neutral line.
2 judge the broken core position of wire (or cable)
The conductor or cable will be heated and aged due to electrodynamic effect or thermal effect, which will cause damage or even fracture of conductor or cable core. Generally, it is impossible to find the broken part without stripping the insulation. A multimeter can be used to accurately and conveniently judge the broken parts of insulated wires or cables, and then repair the damaged parts for continued use. Judge the test wiring as shown in figure 20-4 (two-dimensional code can be scanned for learning).
Test Leads For Multimeter