How to measure appliance leakage with a digital multimeter
Multimeter in our work is still used quite a lot, its main function is to measure resistance, AC voltage, DC voltage. Some multimeters can also measure capacitance, inductance, diode, transistor, level, temperature and so on.
Multimeter by measuring resistance, you can determine the size of the resistance, components good or bad, line through, short circuit, ground fault (leakage) and other phenomena. Through the measurement of voltage, in addition to know the size of the voltage, but also can determine the component good or bad, line through the line, the size of the load, ground fault (i.e., leakage) and other phenomena. Multimeter is generally not used to measure the current, the need to measure the current is generally used clamp ammeter (referred to as clamp meter).
Multimeter how to measure electrical appliances leakage?
In speaking of how to measure electrical appliances leakage before the multimeter, I have to say a premise: the multimeter to determine whether the leakage, only applies to contact leakage or leakage is very serious. (For example, the wire breaks the skin to contact the shell, the circuit board somewhere touches the shell of this case.)
For non-contact leakage, such as due to the wire or insulation strength of the insulator is not enough to occur the leakage of electricity, the multimeter is no way to measure out. This situation must be used to measure the leakage of more professional instrumentation - megohmmeter.
Multimeter resistance gear to measure leakage
First of all, disconnect the power supply, the multimeter to the resistance gear (try to use a large gear), and then a multimeter pen connected to the measured wire or equipment, another pen connected to the equipment shell or shell connected to the ground.
If the multimeter shows zero resistance, it means that the object under test has a leakage, and the leakage is very serious.
If the multimeter shows infinite resistance, the object under test is normal.
If the multimeter shows some resistance, it means that the object under test has a leakage, but the leakage may not be very serious.
Multimeter voltage gear leakage
We can also determine whether there is leakage by measuring whether the equipment shell is charged. Measurement method is to play the multimeter to the voltage gear, a pen connected to the equipment shell, another pen ground (ground must be regular, false ground is meaningless). If a certain voltage is measured, it means that the equipment under test has a leakage; if the voltage is zero, it means that the equipment under test is normal.
