The scope of leakage of electricity line leakage and electrical equipment leakage of electricity both
①Line leakage refers to the leakage current in the line where the load is not connected to the power supply, and the line itself has reduced insulation performance and formed a circuit with the earth.
Leakage of electrical equipment is the leakage current formed by the size of the insulation resistance between the coil inside the equipment and the earth after the equipment is connected to the power supply.
Regardless of what the multimeter, the measured insulation resistance of the line are not standard (measurement of the insulation resistance of the line must be a special megohmmeter), even if you use the multimeter to measure the insulation resistance of the line, but also just a reference value, and with the actual insulation resistance value is very different; because the multimeter itself is a 9V stacked into a battery, for the measurement of the line is only the application of a DC voltage of 9V, while the AC The voltage of the power supply line is 220V, 380V.
If you use a digital multimeter, you can dial the multimeter to the AC current gear.
(1) line leakage is relatively simple to measure, the multimeter to measure the current are connected in series in the line or device, the line in the load are not connected to the power supply, in the power supply circuit breaker output at the lower end (need to disengage the line connector), directly in series in the output of the circuit breaker and the line connector, pay attention to the ordinary digital multimeter just began to dial the current gear a little larger, the above figure for my use of the multimeter for the automatic switching of ranges of the The above figure is the multimeter I use for automatic range switching. At this time the measured current value is the leakage current in the line.
Electrical equipment leakage measurement is very troublesome, because the electrical equipment shell installation are basically mechanical devices grounded, if the multimeter to measure the leakage, you need to vacate the electrical equipment, in the case of equipment energised, with a multimeter with one end of the ground, the other end and the electrical equipment in contact with the multimeter at this time to measure the current for the leakage current.
(2)How to measure the fire wire in the line with digital multimeter? First of all, the digital multimeter will be dialled to AC ~ 750V gear, with the multimeter red pen line or black pen line can be, in their own hands winding 3 ~ 5 circles, the other a pen inserted into or in contact with the conductor's metal stakes or sockets to go. Please see the figure below.
This is the use of wire contact with the human body will form the principle of distributed capacitance (the more the number of turns of the conductor, the greater the capacitance formed with the human body), and the digital multimeter itself is more sensitive than the pointer multimeter. So the reaction to the digital multimeter display value is greater.
Above 1 is a measurement method I often use, generally I am in the hand winding 4 circles, the results of this measurement for ~ 57V, there is no doubt that it is the firewire. Winding in the hand of the pen line does not move, and then use the black pen to contact the other ground line N and PE protection grounding.
This is the use of wire contact with the human body will form the principle of distributed capacitance (the more the number of conductor circles, the greater the capacitance formed with the human body), and the digital multimeter itself is more sensitive than the pointer multimeter high. So the reaction to the digital multimeter display value is greater.
Above 1 is a measurement method I often use, generally I am in the hand winding 4 circles, the results of this measurement for ~ 57V, there is no doubt that it is the firewire. Winding in the hand of the pen line does not move, and then use the black pen to contact the other ground line N and PE protection grounding. Please see Figure 2 below.
At this time, the digital multimeter measurement results show that 000, it shows that the line in the fire, zero, PE protective ground are detected.
