Is the neutral wire live? When is the neutral line electrified

There is no voltage at the neutral line. There is no voltage in the neutral line, and its role in the circuit is also very large. If there is a neutral wire in the line, it can be better connected with the shell of the electronic equipment, once the electronic equipment has the problem of leakage, the neutral wire can make the circuit short-circuit, so as to better protect the equipment from damage.

The neutral line is the line drawn from the neutral point (n) on the secondary side of the generator or transformer, and forms a loop with the phase line (l) to supply power to the electrical equipment. Under normal circumstances, the neutral line is repeatedly grounded (PEN) with the protective ground wire (PE) at the neutral point (N) on the secondary side of the transformer, which plays a double protection role.

Neutral line (n): Mainly used in working circuits, the main trunk line that leads from the neutral point of generators and transformers and is grounded.

In the power plant, the three wires of three-phase electricity are connected together by 120 degrees, and this connection point is called the neutral point, and the line drawn from the neutral point is the zero line! The voltage between phases is called line voltage, and the line voltage in China is 380V, which is industrial electricity. The voltage between any phase and the neutral line is the phase voltage, and the phase voltage in China is 220V, which is household electricity!

In an ideal world, the three-phase load should be about the same, i.e. three-phase balanced, where the neutral line is not charged. However, in the electrical industry, there will always be a few two shortages, and the electrical appliances are added to the first phase line, resulting in a three-phase imbalance and the zero line is electrified. After the statement, if you understand it, it means that you are lying, and you don't understand it, because the main topic is below.

Connect three ropes at one end, intersect them 120 degrees in a plane, and give the other end to three strong men, of course, you can also use the same force to pull, according to junior high school physics and mechanics, you can know that the nodes are not moving. If one of the forces is too strong, the node will move. This is the modeling of three-phase voltage!

At this point, I think you should understand, and then I found out that I was off topic, re! I like to use analogies. The voltage is the height, and the voltage difference is the height difference, because there is a height difference to have a water flow, and the water flow can go to impact.

Kind of understood, right? The voltage difference generates the current, and the current can do work and generate heat! Therefore, if there is no voltage difference, only the voltage is not generated by the current.

It is possible to touch 50,000 volts with your hands and have no effect on yourself, as long as you increase your voltage to 50,000 volts. Ideally, one of the two wires of household electricity is without a dot, that is, the neutral line, if it is set to a voltage reference point of 0V, the voltage of the other is from -220V to 220V, 220V to -220V has been changing, and it has changed very quickly, 50 times per second. That's AC power!

China's industrial electricity consumption is 380V, and the frequency is 50Hz. )。

The voltage of the neutral line to the ground is equal to zero (which itself is connected to the earth). So when one part of the person hits the line of fire and the other part is standing on the ground, and the voltage between these two parts of the person is equal to 220V, there is a risk of electric shock. On the contrary, even if a person uses his hand to grasp the zero line, if the person is standing on the ground, because the voltage of the zero line to the ground is equal to zero, the voltage between the various parts of the human body is equal to zero, and the person is not in danger of electric shock.

Household use is single-phase electricity.

So the incoming wire is the same thickness as the outgoing wire. If the home shares a neutral wire, the current on the neutral wire is as dangerous as the shared live wire, so the current carrying capacity should be calculated for sharing.

Although the household is single-phase electricity, each building in the community is three-phase, one of these three-phase electricity.

Equalization (as close to parity as possible) is distributed to each household, and when the three-phase electrical load is balanced, the midline current is zero, as you know. So with such a distribution, the current back to the neutral line of the power transformer is very small or even zero. <>

The neutral line is electrified, whether it is current or voltage?

The reasons for the voltage are: 1. The zero line is connected and broken; 2. The grounding resistance of the neutral line increases; 3. The three-phase system is unbalanced, resulting in zero drift; 4. Caused by harmonics of the load; If the possibility of breaking the zero line is ruled out, it can be solved by the "zero line voltage treatment device" of Sansi Electric.

There are two reasons for the neutral line current: 1. It is caused by three-phase unbalance, but the neutral line current will not exceed the live wire current. 2. Caused by the third harmonic, the neutral current not only exceeds the live wire current, but also reaches 2 to 3 times of the live wire current.

Solution: 1. In the first case, evenly distribute the three-phase load to avoid the zero line current caused by the three-phase unbalance. 2. In the second case, the installation of Guangzhou Sansi Electric's neutral line current eliminator solves the problem of excessive neutral line current, and the neutral line current elimination rate is more than 90%.

It should be live in the case of neutral line operation.

1. Under normal circumstances, there should be no electricity on the neutral line. Therefore, once there is electricity, it must be a sign of failure; The simplest is electromagnetic induction, and at this time, the zero line is not well grounded and fails to form a loop;

2. The electrical equipment leaks or the phase wire touches the shell, but the current is not large, so it has not tripped. In the three-phase four-wire power supply system, if the neutral line is not well grounded or the ground terminal is broken, the consequence is that the potential of the neutral line is not equal to 0 when the three-phase load is unbalanced, that is, the neutral point is offset.

3. The zero line is broken, making the zero line electrified.

4. In the power grid, there are some grounding in order to protect the electrical appliances, so that the neutral line is live 5. When the long cable is used for power supply, the induction is charged when the electrical equipment is not used, and this phenomenon will automatically disappear when the equipment is used.

6. The zero line is directly grounded, and the system zero line is not connected.

7. The zero line is overlapped with the fire wire.

8. When the three-phase electrical load is unbalanced, zero potential drift will be generated and voltage will be generated.

What is going on with the live zero line 1. There is leakage of electrical equipment on the line, and the protection device does not work, so that the zero line is live. Solution: Power failure for maintenance, find out the leakage equipment for repair, and find the reason for the end of the protection device.

2. There is a phase grounding on the line, and the total protection device in the power grid is protected at the end to make the neutral line live. Solution: After the power failure, first use the shake meter to measure the line to see if the line has bad insulation, and pay attention to the instrument in the line to be disconnected when measuring.

3. The zero line is broken, and there is leakage or a large single-phase load in the electrical equipment behind the fracture, so that the zero line is electrified. Solution: Test whether the zero line is broken after the power failure, and find and repair the broken line.

4. In the zero connection power grid, there are individual electrical equipment that take protective grounding and leakage, so that the zero line is electrified. Solution: Distinguish whether the system is a zeroing system or a grounding system, or a zeroing system has been repeatedly grounded.

Then proceed to install the ground wire correctly. 5. In the zero power grid, there are single-phase electrical equipment that adopts "one fire and one place", that is, there is no working zero line, so that the zero line is electrified. Workaround:

To install the N-line, the PE line cannot be used as an N-line. 6. The insulation resistance of some electrical equipment in the power grid has been damaged and leakage, so that the zero line is electrified. Workaround:

Check the equipment that does not meet the specified requirements for insulation resistance and repair it. 7. The contact at the working grounding connection on the low-voltage side of the transformer is poor, and there is a large resistance in the shouting up, so that the neutral line is charged when the three-phase load unbalanced current exceeds the allowable range. Workaround:

It is not easy to find poor contact, and it is necessary to overhaul it every year or at the specified time, and it is not lazy to be overhauled according to the regulations. 8. The high voltage is channeled into the low voltage, so that the neutral line is electrified. Workaround:

It's hard to find, and sometimes something goes terribly wrong. The most difficult one to deal with, dangerous to people. Be sure to follow the operating procedures.

9. When the grounding body is too close to the low-voltage working grounding or repeated grounding body, the voltage drop on the high-voltage working grounding will affect the working grounding on the low-voltage side and make the zero line electrified. Solution: Find out the cause and lay according to the corresponding procedures.

10. The magnetic field induction causes the neutral line to be charged. Solution: Prevent magnetic field induction.

11. Electrostatic induction causes the neutral line to be electrified. Solution: Prevent electrostatic induction.

This is normal, but it cannot be used, if the neutral and ground wires are accurately measured, there should be a ground resistance of more than 4-10 ohms.

The neutral wire is grounded at the distribution ring box or the transformer return to the trapped end, so it is normal to measure the conduction between the neutral wire and the ground wire, but this does not mean that the neutral wire and the ground wire are connected.

In the three-phase five-wire system, the neutral wire and the ground wire must be connected separately, if the three-phase unbalance or other electrical appliances are unbalanced, affected by the internal resistance of the wire, the potential of the neutral wire will deviate from the ground potential; The total return current of the neutral line must be zero with the sum of the phase current vector, otherwise it will be considered as leakage, and leakage protection will occur.

Because the neutral line is cut off, the reed gets the lower electric hail pressure brought by the induction electricity or the equipment is electrified. The zero line should never be electrified, nor should it be interrupted by the source to prevent hidden dangers.

The neutral wire will be energized when the circuit is working normally and when the neutral wire is faulty to ground.

1. When the circuit is working normally.

The circuit is working normally, that is, the live wire and the neutral wire have been connected, and at this time there is a continuous current passing through the circuit. At this time, if you touch the neutral line, you will be electrocuted.

2. When the neutral line is grounded in a fault.

When the neutral line is faulted to ground, the electric potential between the neutral line and the ground becomes different. At this time, when the human body touches the zero line, the fault zero line will form a path with the human body and the earth, resulting in an electric potential difference, and the zero line will also be electrified.

In general, the live neutral line is caused by the disconnection of the neutral wire. After the neutral line is broken, the neutral line can also make the electric pen shine due to induction, or the live wire will reach the broken neutral line after passing through the electrical appliance, then the neutral line will be electrified.

Another situation is that the zero line contact is poor, the resistance is relatively large, and there will be a voltage difference between the zero line and the ground. The live wire is live because the live wire is connected to the power supply, and the neutral wire is not connected to the power supply, so the live wire is electrified.

What is going on with the live zero line 1. Poor contact of the zero line: In a certain wire circuit, the joint of the zero line is not in good contact, which leads to an increase in the resistance of the zero line, so the situation that the zero line is live. 2. The zero line is broken:

The neutral wire is disconnected somewhere due to aging and other reasons, and its resistance becomes infinite, which will cause the neutral wire to be electrified. Or the wire is short-circuited, which damages the surface of the wire insulation, causing the neutral wire to be connected to the live wire, so the neutral wire will be electrified. 3. Grounding of the live wire:

The grounding of the live wire will cause the ground to no longer have zero potential, and when we measure the zero line with a tool such as a multimeter, the zero wire will be electrified. 4. Poor grounding: If the ground wire is in poor contact or the grounding device is faulty, it will lead to the problem of live electricity in the zero line voltage.

Of course, this neutral wire and the live wire form a loop, so that the current can circulate and there will be electricity!

The so-called zero line has no electricity is the ideal state, and the current flows from high potential to low potential, in fact, the zero line is also the channel of current.

Usually the live wire has always had a high potential, so it will be numb, and the zero line is connected to the zero potential before the switch is not closed, but the current will flow back to the transformer from the zero line after the switch is closed, so the zero line is voltage.

Or the neutral line is generally the trunk line after the neutral point of the transformer is grounded, which is mainly used in the working circuit, and the voltage generated by the neutral line is equal to the line resistance multiplied by the current of the working circuit.

Due to the long distance transmission, the voltage generated by the neutral line cannot be ignored.

So you're right when you say there's electricity.