How to Ground and Zero Reverse What is the difference between ground and zero

The neutral line is introduced from the neutral point of the transformer.

The ground wire is directly connected to the earth.

When the neutral point is not grounded and the system is not connected to the neutral point (such as a single-phase grounding short circuit), it will cause the potential drift of the neutral point, and the neutral point potential will be raised, and the phase voltage will be raised to the line voltage, which will endanger the safety of the equipment.

Therefore, the electrical equipment can work normally when there is no failure, but when there is an asymmetric short circuit, the neutral point potential will be raised, endangering the electrical equipment.

This is the reason why equipment such as switches in some units is often damaged.

If you don't plug it in, there is no response, and the machine will not run.

Or burn it.

It shouldn't burn, it will run unstable, depending on what kind of machine it is.

Legend has it that in the past, there was a way to save power by replacing the neutral wire with the ground wire, which would be more dangerous.

Grounding is a protective measure taken to prevent accidents caused by equipment leakage, and zeroing is a measure taken to prevent damage to the power grid and equipment caused by zero drift due to load imbalance.

It depends on what system you are using and what kind of protection you have installed.

If the ground wire (PE) and neutral wire (N) are not disconnected, it can operate normally, but sometimes when the phase wire is short-circuited with the equipment shell, the shell may be charged and hurt people;

When a leakage protector is used, the reverse connection will trip at the moment when the device is started and cannot work.

Grounding protection, also known as the third grounding protection measure, is to connect the equipment shell that may leakage to the ground with a reliable grounding wire. Zero protection is to connect the equipment shell to the neutral wire after the power transformer side of the centralized grounding, because the power line in the zero line may have a relatively large orange mode current, the zero line may have the risk of poor joint heating contact, so the reliability of the zero line protection is relatively poor.

According to the relevant safety regulations, the shell of the electrical equipment used shall have (protective grounding or zeroing) protective measures.

1. The principle and function of protective grounding.

Protective grounding is the grounding carried out to prevent the metal shell of the electrical installation, the frame of the power distribution device and the line tower from being charged to endanger the safety of people and equipment. The so-called protective grounding is a protective wiring method that reliably connects the metal part of the electrical appliance (that is, the metal structure part insulated from the live part) that is not charged under normal circumstances and may be charged after the insulation material is damaged or under other circumstances.

Grounding and zeroing.

Second, the principle and function of protection zero.

It is an electrical safety measure that connects the metal shell of electrical equipment with the neutral line of the power grid to protect personal safety. In the low-voltage zero power grid, if the electrical equipment is energized due to insulation damage or accidents, a single-phase short circuit of the phase line to the neutral wire is formed, and the protection device on the line acts quickly to cut off the power supply, so that the metal part of the equipment will not have a dangerous voltage for a long time, which ensures personal safety.

3. The reason why protective grounding and protective zero cannot be mixed.

Protective grounding and protective zero connection are a measure to ensure personal safety, that is, the live equipment shell is reliably grounded or zeroed, and when it fails, quickly start the protection equipment to cut off the power supply to ensure personal safety. However, in the same transformer system,You can't use both at the same time (on the same device), what is the principle?

Because when the protective grounding equipment shell is live, if its grounding resistance r is larger, the fault current id is not enough to make the protection device act, then because of the existence of the working resistance rd, the voltage u0=id*rd has been present on the neutral line, at this time, there is a dangerous voltage u0 on the shell of the protective grounding equipment for a long time, endangering personal safety.

For the connection of wires, many people are not very clear, after all, this is a more technical work, such as ground wire, live wire and neutral wire, this is a more common wire in the circuit connection, some people in the connection of the destroy, often will be reversed, this practice is actually very dangerous, so the ground wire and the zero wire connection number will be reversed what will happen? Let's take a look at it below, I believe it will bring you different insights.

It can cause a short circuit in the circuit or the neutral line will be blown off. If the zero wire is burned, the shell of the electrical appliance is equivalent to the fire wire, once the human body is in contact, it will be shocked, which poses a threat to personal safety, even if the leakage protector is installed at home, the leakage protection switch will not trip when it does not touch the shell of the electrical appliance, so pay attention to it when wiring.

What to pay attention to for the grounding wire.

1. One circuit and one grounding wire are more reliable.

Although the current generated by the ground wire will be relatively small under the normal operation of the wire, in the event of a short circuit, the current in the ground wire will greatly exceed the current of the phase wire. Therefore, in order to make the circuit more stable, a circuit should be connected to a ground wire, which will be more reliable.

2. With a good grounding device, the leakage switch should still be configured.

If the electrical equipment shell is in a live condition, even if the resistance to the ground is small, there is a possibility of electric shock before the fault is lifted. Therefore, for the safety of use, it is recommended to install a leakage switch, so that even if leakage occurs, it will trip immediately and disconnect the circuit to ensure personal safety.

3. With leakage protection, there should also be grounding protection.

Although the leakage switch has a certain protective effect, it is also possible to fail. Therefore, even if leakage protection is installed, the circuit is also a hole that needs to be grounded for protection, so that even if the leakage switch fails, the grounding protection can play a role in protection.

Summary: The above about the ground wire and the neutral wire will be reversed, what needs to be paid attention to the grounding wire is introduced here, I hope to provide you with some help. If you want to know more about decoration, you can pay attention to the relevant information of Qeeka Home.

Dear I am happy to answer for you, my answer is as follows [happy closed mu blind] the following situations will occur when the ground wire is reversed, the following is my personal experience, I hope it can help you The ground wire and the zero line are reversed will cause a short circuit or the zero line will be burned, if the zero line is burned, then the shell of the electrical appliance is equivalent to the live wire, once the human body is in contact, it will be shocked, which poses a threat to personal safety, even if the leakage protector is installed at home, the leakage protection switch will not trip if it does not touch the electrical shell, so pay attention when wiring. It will also cause the shell of household appliances to be directly electrified, and if people happen to touch this appliance at this time, it will lead to the occurrence of dangerous accidents that touch dust-resistant electricity. Now most of the cars are installed with leakage protectors, so after the neutral line and ground wire are reversed, it will lead to the problem of tripping the leakage protector.

If the leakage protector is not installed, it will lead to damage to household appliances, and even cause fire, electric shock accidents and other risks.

The main differences between protective grounding and protective zeroing are listed below:

1.The principle of protection is different:

Protective grounding is to limit the voltage to the ground after the leakage of the equipment so that it does not exceed the safe range. In the high-voltage system, in addition to limiting the voltage to the ground, the protective grounding also has the effect of promoting the action of the power grid protection device in some cases

The protection of zero connection is to make the equipment leakage form a single-phase short circuit with the help of the zero connection line, promote the action of the protection device on the line, and cut off the power supply of the faulty equipment. In addition, in the case of a protected zero-connected grid, the protective neutral and repeated grounding also limit the voltage to ground when the equipment leaks.

2.The scope of application is different:

Protective grounding is suitable for high and low voltage power grids that are generally not grounded, and also suitable for low-voltage power grids that have taken other safety measures (such as installing leakage protectors); The protection zero connection is only suitable for low-voltage power grids where the neutral point is directly grounded.

3.The line structure is different:

If protective grounding measures are taken, there can be no working zero line in the power grid, and only a protective grounding line can be set; If protective zero connection measures are taken, a working zero line must be set up, and the working zero line must be used for zero connection protection. The protective neutral wire should not be connected to the switch and fuse, and when the fuse and other interrupting appliances are installed on the working neutral line, the protective grounding wire or neutral wire must also be installed.

The enclosure of electrical equipment is grounded or zeroed to ensure the safety of personnel.

Direct grounding is best, but there must be a qualified grounding wire.

grounding grid or grounding device).

When there is no condition to ground, only zero can be connected. Although the neutral line is also grounded at the transformer, the three phases are unbalanced because there is a certain distance from the grounding point.

The current has a certain voltage drop across the neutral line, so the neutral line is often not zero. (sometimes up to tens of V).

Even so, there is still a certain value of protection for zeroing.

Zeroing is when the neutral line is grounded at the power station or distribution station, whereas grounding is when it is grounded near the home. I guess it's a difference in distance.

The premise of your question should be protection. Zeroing is the connection between the shell of the electrical equipment or other metal structures that may leak electricity and the neutral wire, and the grounding is connected to the ground wire.

That's not right, the one above. The function of the neutral wire is to form a loop, and the role of the ground is to protect, and in the TN C system, the neutral wire and the ground wire are the same, so don't get it wrong.

In a grid with neutral point insulated from the ground, when the live part accidentally touches the metal shell of the electrical equipment, the ground current will form a loop through the capacitance between the human body of the contact equipment and the grid and the earth. At this point, the ground current flowing through the fault point is mainly the capacitive current. In general, this current is not large.

However, if the grid is widely distributed, or if the dielectric strength of the grid is significantly reduced, this current can reach a dangerous level, which necessitates safety measures.

If the electrical equipment has taken protective grounding measures, the current through the human body is only a part of the total grounding current, because the grounding resistance and the human body resistance are connected in parallel, the smaller the grounding resistance, the smaller the current flowing through the human body, if the grounding resistance is limited within the appropriate range, personal safety can be guaranteed. Therefore, in this neutral ungrounded (insulated) system, all metal parts (normally uncharged) that may present a voltage to ground due to insulation damage should be grounded. This is called protective grounding.

The so-called protection zero connection is to closely connect the uncharged metal part of the electrical equipment with the zero line of the power grid under normal circumstances, which effectively plays a role in protecting the safety of people and equipment.

In a three-phase four-wire system where the neutral point of the transformer is directly grounded, a protective zero connection is usually used as a safety measure, in this case, if a live phase part touches the equipment housing, a single-phase short circuit of the phase line to the neutral line is formed through the equipment housing. The short-circuit current always exceeds the normal working current many times, which can make the protection device on the line act quickly, so that the fault part is removed from the power supply and ensure safety. In the 380 220V three-phase four-wire system neutral directly grounded power grid, regardless of the environment, all metal parts that may present a voltage to ground due to insulation damage should be connected to zero.

Zero connection refers to the connection between the metal and the neutral wire of the three-phase power supply of the metal of the shell of the electrical equipment, which is called the neutral zero.

Grounding refers to the connection between the metal of the shell of the electrical equipment without points and the earth with a wire, which is called grounding, also known as repeated zeroing.

The principle of protection is different:

The basic principle of low-voltage system protection grounding is to limit the voltage of leakage equipment to the ground, so that it does not exceed a certain safety range, and the protection grounding of high-voltage system, in addition to limiting the voltage to the ground, in some cases, also has the effect of promoting the action of the protective device in the system. The main function of zero connection is to make the equipment leakage form a single-phase short circuit by connecting the zero line line, and promote the rapid action of the protection device on the line; Secondly, the protection neutral line and repeated grounding in the zero connection system also have a certain pressure reduction effect.

The scope of application is different:

Grounding is suitable for general low-voltage neutral ungrounded power grids and low-voltage grounded power grids with other safety measures, and grounding can also be used in high-voltage non-grounded power grids. Zeroing is suitable for low-voltage grids where the neutral point is directly grounded, and non-grounded grids do not need to be zeroed. The line structure is different:

In addition to the phase wire, the grounding system only has a protective ground wire.

In addition to the phase wire, the zero connection system must have a zero line; If necessary, the protection neutral line should be separated from the working neutral line; Its repeated grounding device should also have a ground wire.

Added: Similarities between zero and ground.

In the low-voltage system, it is a technical measure to prevent electric shock accidents caused by leakage.

Requiring grounding measures is about the same as requiring zeroing measures.

Both grounding and zero require a certain grounding device, and the construction and connection of the grounding body and grounding wire of each grounding device are basically the same.