What gear does the leakage multimeter play? How to measure leakage with digital multimeter
Measure the ground voltage of the equipment with AC voltage when it is energized. In the case of power failure, measure the grounding resistance of the electrified part with electric block.
Serious leakage can be found out by using the resistance file of multimeter, but if the leakage is not serious, the multimeter can't measure it; There are special insulation resistance testers for measuring insulation, such as shaking table and digital megger, which can simulate the real working voltage, and the test voltage of multimeter is very low.
First, ask the repair user what the fault phenomenon is and what the obvious characteristics are; Secondly, observe whether there is any intuitive fault point from the surface, and then carry out the next inspection.
1. First disconnect the main isolating switch of the user's power supply, and turn off all power loads of the user, such as unplugging the refrigerator and disconnecting the water pump switch.
2. Put the gear of the digital multimeter on the 200M gear of the ohm gear, put one stylus on one of the two outgoing lines on the load side, and touch the wall with the other stylus, preferably touching the grounding wire or temporary grounding wire. After the number displayed on the multimeter is stable, the insulation resistance value of the main line is read out. If the insulation resistance value is less than 0.5 megohm, there is something wrong with the main line. If the insulation resistance is above 0.5 megohm, it can be ruled out that there is something wrong with the main line. Measure the other wire in the same way, and also check the value to see if there is something wrong with the main line.
3. Check the insulation resistance values of the shunt and all electrical appliances, and test them one by one in the same way until the fault point is found.
Precautions for operation
1. When using the 200M block of the multimeter ohm block, be careful not to touch the metal part of the stylus by hand during measurement, which will make the reading inaccurate.
2. Pay attention to discharge first when measuring each electrical equipment to prevent the capacitive current in the electrical equipment from hurting people.
This method is a safe way to find the fault point when there is no electricity. This method is also suitable for power users and power plant leakage search, but when searching, it is necessary to disconnect not only the incoming line of power supply, but also the zero line to avoid electric shock accidents.
