A multimeter is an essential measuring instrument in electrical and electronic departments. As temperatures gradually drop and rainy, humid weather increases, the number of reports regarding electrical leakage faults has also risen. I believe many friends have been thinking hard about finding the cause of electrical leakage.
In fact, we can easily find the cause of leakage using the multimeter at hand. So today, let’s learn how to detect electrical leakage with a multimeter.
Detecting Car Battery Leakage with a Multimeter
Step 1: Disconnect the negative terminal of the battery.
Step 2: Insert the red probe into the 20A current socket and turn the dial to DC 20A.
Step 3: Connect the red probe to the battery wire and the black probe to the battery terminal. You can also reverse the probes.
Step 4: At this point, the reading on the multimeter indicates the leakage current.
How to Use a Multimeter?
1. Familiarize yourself with the multimeter’s functions before use. Select the correct range and socket according to the object being measured.
2. If the size of the measured data is unknown, set the range switch to the maximum value, then switch from large range to smaller ranges until the meter pointer indicates above half of the full scale.
3. When measuring resistance, after selecting the appropriate range, touch the two probes together to make the pointer indicate zero. If the pointer deviates from zero, adjust the “zero adjustment” knob to bring the pointer back to zero to ensure accurate measurement. If zero adjustment is not possible or the digital display shows a low voltage alarm, check immediately.
4. When measuring the resistance of a circuit, ensure that the power supply to the measured circuit is turned off; do not measure while powered.
5. When measuring with a multimeter, pay attention to personal and equipment safety. Do not touch the metal parts of the probes with your hands during the test, and do not switch ranges while powered to ensure accurate measurements and avoid electric shock or damage to the instrument.
How to Detect Electrical Leakage with a Multimeter?
1. First, disconnect the main isolation switch of the user power supply and turn off all electrical loads, such as unplugging the refrigerator and turning off the water pump switch.
2. Set the digital multimeter to the 200M ohm range. Place one probe on one of the two outgoing lines on the load side, and the other probe to touch the wall, preferably touching the grounding line or a temporary grounding line. Once the number on the multimeter stabilizes, read the insulation resistance value of the main line. If the insulation resistance is less than 0.5 megaohms, there is a problem with the main line; if it is above 0.5 megaohms, the main line can be ruled out as the issue. Use the same method to measure the other wire and check the value to see if the main line is the problem.
3. Check the insulation resistance values of the branch circuits and each electrical appliance one by one until the fault point is found.
Operational Precautions
1. When using the 200M ohm range on the multimeter, be careful not to touch the metal parts of the probes during measurement, as this will lead to inaccurate readings.
2. When measuring each electrical device, be sure to discharge first to prevent electric shock from capacitive current in the electrical device.
This method is a relatively safe way to find fault points in a de-energized state. This method is also applicable for finding leakage in power users and factories, but when searching, not only should the power supply be disconnected, but the neutral line should also be disconnected to avoid electric shock accidents.
After reading the above article on how to detect electrical leakage with a multimeter, I believe everyone should have a basic understanding of how to use a multimeter.
A multimeter is a magnetic-electric instrument equipped with a rectifier that can measure AC and DC current, voltage, resistance, and various other electrical parameters, primarily for measuring voltage, current, and resistance.
In some high-end cars, there are many computer modules; we need to wait for them to enter a sleep state before measuring the leakage current for accurate results.
Remove the car keys and take them far away from the car.
The image above shows an incorrect operation method; the key is still within the car’s sensing range. At this point, the key and the vehicle are communicating. If leakage current is measured, it will not be accurate.
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