How is it that the zero line is a little bright when the switch controls the live wire with a pencil?
First of all, it should be clear that the zero line will not be charged under normal circumstances, regardless of whether the live line (technical term is phase line) is disconnected or not. If the neutral line is charged, it means that there is a problem somewhere on the line, so how can we find out where the problem is? For ordinary electricity customers, share a simple and practical quick search and handling method:
First, to describe this problem, the reason for this phenomenon is that the zero line is slightly bright, which is generally caused by oxidation at the zero line lap joint, resulting in poor contact. However, this situation can be ruled out as the disconnection of the zero line of the main line, because the fault phenomenon and consequences caused by the disconnection or poor contact of the zero line of the main line are different, so I will not analyze it here.
Second, segment search and narrow the scope. First, check whether the zero line of the upper and lower pile heads of the switch is normal when the main switch is in the closing position. If the zero line is normal and there is no electricity, it is generally a problem in the latter part of the switch. You can check the joint on the line segment by segment, and find the fault point and then rewire it. Because the problem is usually at the line connection. This kind of situation occurs most often, which is generally the old power lines long ago. Now the indoor wiring and installation are very scientific, so this kind of problem will not appear generally.
3. If there is no electricity at the zero line of the upper pile head and electricity at the lower pile head when the switch is checked, this situation is generally that the switch is broken, and the switch can be opened and closed several times, and sometimes the electricity can be temporarily restored, but the switch should be replaced in time.
When checking, if the zero line of the pile head on the switch is also charged, this situation can only be repaired by calling, because there may be a pole inspection, which the user can not easily solve.
There are two possibilities. First, some wall switches have an indicator light connected to the switch in order to let users find the switch position smoothly in the dark. When the switch is off, this indicator light still has a small current passing through the switch. Secondly, all fluorescent lamps, whether ordinary fluorescent tubes or energy-saving lamps, have certain delayed extinguishing characteristics, which are called "afterglow". Now with the progress of science, with LCD and corresponding display circuit, things that don't happen at the same time can be easily displayed in the same picture, such as ECG monitor, which shows a horizontal line that fluctuates up and down with the heart beating, but in fact all the fluctuations on this horizontal line are not things that happen at the same time, but a time process. In the past, when there was only CRT display, only one point fluctuated with the heartbeat. In order to display a line, we had to choose a "long afterglow" display, so that the scanning point did not go out immediately after passing, but slowly went out after a long time, which made the movement of a point become a line display. And the oscilloscope at that time was the same principle.
The neutral line is the loop of all electrical equipment. Because the neutral line has a certain resistance, the greater the resistance or current of the neutral line, the higher the corresponding voltage. Therefore, it is possible that the zero line is not completely voltage-free, and the pencil is slightly bright. Of course, if the neutral circuit has poor contact, it will make the neutral voltage high. So it's best to measure the voltage with a voltmeter.
The open circuit of one phase fuse of transformer will also cause the zero line to be dimly lit by electric pen. When a motor burns out and a phase is grounded by the motor, it will also cause the zero line to be dimly lit by electric pen. When the zero line is disconnected from the power supply, the zero line will also be measured by electrical appliances. The electric pen is brighter.
Quite simply, as long as the neutral circuit is well conducted, this phenomenon is impossible. If this happens, there must be a disconnection or poor conduction somewhere in the zero line loop or a series connection with electrical appliances. The solution is to connect the disconnected or poorly conducted parts of the neutral circuit firmly. If two electrical appliances are connected in a circuit in series, one electrical appliance will be removed and only one electrical appliance can be kept.
