Leakage test method of digital multimeter
Generally, the AC voltage gear is used to measure the ground voltage of the equipment, and the resistance gear is used to measure the ground resistance of the energized part in the case of power failure.
For serious leakage problems, you can use the resistance gear of the multimeter to find out, but the leakage is not serious, and the multimeter cannot measure it. When measuring insulation, you can use an insulation resistance tester, such as a shaker, a digital megohmmeter, etc. These tools can simulate the real working voltage, and the test voltage of the multimeter is very low.
First ask the user for repairs what fault phenomenon has occurred and what obvious features have appeared; then, observe whether there is an intuitive fault point from the surface, and then proceed to the next step of inspection.
1. Disconnect the main isolation switch of the user's power supply line, and turn off all the electricity loads of the user, such as unplug the refrigerator, disconnect the water pump switch, etc.
2. Put the gear of the digital multimeter on the 200M gear of the ohm gear, put one test lead on one of the two outlet wires on the load side, and the other test lead touches the wall, preferably touching the ground wire or temporarily grounding Wire. After waiting for the number displayed on the multimeter to stabilize, read out the insulation resistance value of the main line. If the insulation resistance value is less than 0.5 megohm, then there is a problem with the main circuit. If the insulation resistance is above 0.5 megohm, it can be ruled out that it is the main circuit. There is a problem with the wiring. Measure the other wire in the same way, and also check the value to see if there is a problem with the main wire.
3. Check the insulation resistance value of the shunt and each electrical appliance, and use the same method to test one by one until the fault point is found.
