What is the gear of the leakage multimeter? How to measure the leakage with a digital multimeter
When the power is on, use the AC voltage file to measure the voltage of the equipment to the ground. In the case of power failure, measure the resistance to ground of the energized part with an electric barrier.
Severe leakage can be detected by the resistance of the multimeter, but if the leakage is not serious, the multimeter cannot measure it; there are special insulation resistance testers for measuring insulation, such as shaking meters, digital megohmmeters, etc., which can simulate real work Voltage, the test voltage of the multimeter is very low.
First ask the repairing user what is the fault phenomenon and what are the obvious features; secondly, observe whether there is an intuitive fault point from the surface, and then proceed to the next step of inspection.
1. First disconnect the main isolating switch of the user's power incoming line, and turn off all the user's electrical loads, such as unplugging the refrigerator, disconnecting the water pump switch, etc.
2. Put the gear of the digital multimeter on the 200M gear of the ohm range, place one test lead on one of the two outlets on the load side, and the other test lead touch the wall, preferably the ground wire or temporary Ground wire. After the number displayed on the multimeter is stable, the insulation resistance value of the main line is read. If the insulation resistance value is less than 0.5 megohm, then there is a problem with the main line. If the insulation resistance is above 0.5 megohm, it can be ruled out. It's a problem with the main line. Use the same method to measure another wire, and also check the value to see if there is a problem with the main line.
3. Check the insulation resistance value of the shunt and each electrical appliance, and check one by one in the same way until the fault point is found.
Operation precautions
1. When using the 200M block of the ohm block of the multimeter, be careful not to touch the metal part of the test lead with your hands when measuring, otherwise the reading will be inaccurate.
2. When measuring each electrical equipment, pay attention to discharge first to prevent the capacitive current in the electrical equipment from hurting people.
This method is a relatively safe way to find the fault point in the state of no electricity. This method is also applicable to power users and factory building leakage search, but when searching, not only the power supply line should be disconnected, but also the neutral line should be disconnected to avoid electric shock accidents.
