Fault Diagnosis and Analysis of Digital Multimeters
As the temperature gradually rises, rainy and humid weather is also increasing, and there are more reports of faults caused by electrical leakage. I believe friends have been thinking a lot about finding the cause of electrical leakage. In fact, we can easily identify the cause of electrical leakage by using what we have in our hands.
Fault finding and analysis
First, inquire about the fault symptoms and obvious features of the user who reported the repair; Next, observe the surface for any obvious
fault points, and then proceed to the next step of inspection.
1. First, disconnect the main isolation switch of the user's incoming line and turn off all electrical loads of the user, such as unplugging the refrigerator plug, disconnecting the water pump switch, etc.
2. Place the gear of the digital multimeter in the 200M range of the ohm range, with one probe placed on one of the two output lines on the load side and the other probe touching the wall, which can be touching the grounding wire or temporary grounding wire. After the number displayed on the multimeter stabilizes, the insulation resistance value of the main circuit is read out. If the insulation resistance value is less than 0.5 megohms, then there is a problem with the main circuit. If the insulation resistance is above 0.5 megohms, then it can be ruled out that there is a problem with the main circuit. Measure another wire using the same method and check the value to see if there is a problem with the main circuit.
3. Check the insulation resistance values of the branches and various electrical appliances, and use the same method to detect them one by one until the fault point is found.
Operation precautions
When using the multimeter in the 200M ohm range, be careful not to touch the metal part of the probe with your hand during measurement, as this will result in inaccurate readings.
2. When measuring various electrical equipment, pay attention to discharging first to prevent capacitive currents in the equipment from injuring people.
This method is a relatively safe way to locate the fault point in a state of no electricity. This method is also applicable to the search for power users and factory leakage, but during the search, not only should the power supply line be disconnected, but also the neutral line should be disconnected to avoid electric shock accidents.
