Multimeter measurement of electrical equipment enclosure leakage method
Multimeter measurement of electrical equipment shell leakage method.
Electrical equipment metal casing if the insulation is good, and reliable grounding is not leakage, but sometimes the equipment insulation is not good or grounding is not reliable (common in factories is the grounding of the equipment is directly connected to the metal casing sprayed with plastic powder), at this time the metal casing will be charged, so we use a digital multimeter AC voltage file to measure the voltage between the metal casing and the ground to know whether the equipment leakage.
Measurement, the digital multimeter dialled to AC 200V file, with the red pen contact equipment casing, the black pen connected to the earth, at this time if the multimeter shows more than a few tens of volts of voltage, indicating that the equipment insulation is not very good, or grounding is not reliable. If the measurement shows that the voltage reaches one hundred and ten volts, this time the hand touching the metal casing of the equipment will generally have the feeling of electric shock. At this point we can measure the size of the leakage current, the multimeter dialled to AC 2mA (or 20mA) gear, with the red pen contact equipment housing, black pen to earth, the current displayed at this time that is the leakage current, the size of which is generally in the μA level.
