How to use a multimeter to measure the leakage of a 220V line
Multimeter measurement of 220V leakage is not quite appropriate, because you want to measure the leakage current, multimeter measurement of weak AC current is weak, measurement is not allowed is also more troublesome, if you have to measure, you need to use the current transformer, you might as well use the clamp meter to measure, but to choose the range of the appropriate sensitivity of some good clamp meter.
Suspected circuit leakage, you can use the open air with leakage protection to judge, segment by segment to determine the scope of the leakage, troubleshooting.
As for the resistance to measure the line leakage, I think it is not appropriate. Because since it is a leakage, that is, the resistance between the firewire and the protective ground is not infinite, but the multimeter voltage is not enough to explain the insulation between them, that is, 9V and 220V insulation resistance is very different. Therefore, the insulation resistance is measured at a higher voltage than that of the power supply to obtain reliable data. That's why you have to use a rocking meter.
Of course, if you just measure whether there is a short circuit or path between the firewire and the protective earth, using a multimeter resistance block is also possible. You just can't measure the insulation data between them.
Strictly speaking, to measure whether a line insulation resistance circuit is leaking or not you should use a rocking meter, which is equivalent to a 1000v or 500v generator, where the leakage current passes through the sampling resistor inside the rocking meter and produces a sampling voltage indication on the resistor. Typically, a stable greater than 0.5 megohms is qualified. Multimeter internal battery 9v to 15v, resistance file and voltage file can only determine the short circuit, roughly determine whether the leakage.
1, power measurement: close and disconnect all electrical appliances, with a multimeter RX10K file, a pen reception measurement of the firewire, the other pen ground (or tap), should show the resistance of infinity, otherwise leakage.
2, charged measurement: with a multimeter 250 volts AC voltage file, measuring suspected leakage of the metal shell of the appliance, a pen connected to the shell, another pen ground (or tap), the pointer shows a voltage higher than 30-50 volts between, change the AC 50-volt gear, if the power supply to confirm that higher than 30 volts is a leakage, lower than 30 volts is normal, and then zero, the fire power supply plug line to the opposite measurement can be determined once again. If the power supply is confirmed to be higher than 30 volts, the leakage is below 30 volts.
3, fire and zero line (or fire and fire) between the leakage measurement: close and disconnect all electrical appliances, measuring the resistance between the fire and zero line should be infinite, otherwise it is a leakage.
The above method of troubleshooting accuracy of 99.9%, convenient, rapid, practical, and megohm special shaking table just to do the project must be used, the maintenance of the use of inefficient, only the multimeter to confirm the measurement of a good, but the line is indeed a leakage, the use of shaking the table, but the multimeter does not come out of the leakage!
