How to measure electric leakage with a digital multimeter
Use the AC voltage range of the digital multimeter to measure the leakage voltage of the electric soldering iron.
When using the AC voltage range of the digital multimeter to measure the leakage voltage of the electric soldering iron, first adjust the digital multimeter to the AC voltage range (the digital multimeter with automatic range change is used in the figure), then touch the tip of the soldering iron with one test lead, and the other test lead Contact the ground wire (or earth), then the AC voltage displayed by the multimeter is the leakage voltage. If the soldering iron is not grounded, the tip of the soldering iron will have a higher leakage voltage at high temperatures. Since the grounding end of the soldering iron plug in the figure is round, it cannot be inserted into a general socket (it can be inserted with a universal five-hole socket), so the grounding end of the plug is cut off. Although the socket has a ground wire, the electric soldering iron is not grounded, so there is a leakage voltage.
During the test, the red test lead is connected to a screw through a small piece of solder wire, and this screw is connected to the ground wire of the socket on the production line. In the figure above, the measured leakage voltage is 42.51V. It can be seen that the leakage voltage of the ungrounded electric soldering iron is still high at high temperature.
When the soldering iron is not connected to the power supply, the AC voltage displayed by the multimeter is only 20.9mV.
When the soldering iron is not connected to the power supply, the AC voltage displayed by the multimeter is only 20.9mV. This reading is an interference signal of the AC voltage range, and the number is constantly changing. It can be seen from the figure that the ground end of the temperature-adjusting soldering iron plug has been cut off.
2. Measure the leakage current with a digital multimeter
Measure the leakage current of the electric soldering iron with the AC current range of the digital multimeter.
When using a digital multimeter to measure the leakage current of electrical equipment, first adjust the multimeter to the AC current range (if it is not a multimeter that automatically changes the range, adjust the range switch to the minimum AC current range) and then connect the red and black test leads as described above. The reading displayed by the multimeter is the leakage current. The figure above shows that the leakage current of the soldering iron is 5.4μA.
