Precautions for checking line leakage with multimeter
The reason for the leakage, I believe that many friends have used a lot of brains to find the cause of the leakage. In fact, I tell you that you can easily find out the cause of the leakage with a multimeter in your hand.
Fault Finding Analysis
Before analyzing where the leakage occurs, we must first look at the fault phenomena and obvious features in the home; secondly, observe whether there are intuitive fault points from the surface, and then proceed to the next step of inspection.
1. First disconnect the main isolating switch of our power inlet 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 gear, place one test lead on one of the two outlets on the load side, and the other test lead touch the wall, preferably the grounding wire or a temporary Ground 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, then there is a problem with the main line. If the insulation resistance is above 0.5 megohm, it can be ruled out that there is 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 use the same method to check one by one until the fault point is found.
Operation precautions
1. When using the 200M gear of the ohm gear of the multimeter, be careful not to touch the metal part of the test pen with your hands when measuring, otherwise the reading will be inaccurate.
2. When measuring various 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 use a multimeter 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.
