Firstly, measure the leakage voltage with a multimeter. Place the multimeter switch on the AC voltage measurement range, usually at the AC voltage 250V range. Then, insert the black probe into the soil near the tested equipment and the red probe into the metal casing of the equipment. At this point, look at the reading on the multimeter. If the needle does not move, you can gradually shift it to a lower gear until the specific data is indicated, which is the leakage voltage of the device. If there is still no indication when the probe is in the low range, it means that there is no leakage phenomenon in the device.