Lead
"The zero line is not electrified, why do you need to pull a single zero wire, isn't it more cost-effective to use the ground wire directly?"
This is a very common problem for many people in the daily construction process of electricians, in fact, in the power system, the neutral wire and the ground wire have completely different roles.
So in the power system, why is there a separate neutral wire?
What is the role of the zero line?
1. TN-S system.
As the most common and most commonly used power system in the power system, the TN-S system is the first choice for low-voltage distribution systems.
TN-S system refers to the zero connection protection system set separately from the working zero line and the protection zero line, which fundamentally ensures the safety of our electricity.
The N-line in the TN-S system is the neutral line pointed out in the center, which is higher in safety than the TN-C-S system.
Because in the TN-C-S system, the neutral wire and the ground wire are shared, when there is a problem with the neutral wire, it will lead to problems with electrical safety, while in the TN-S system, the neutral wire and the ground wire are separated, so when there is a problem with the neutral wire, it will not affect the safety of electricity.
However, this will also cause a new problem, that is, there is a certain potential difference between the neutral wire and the ground wire, which can easily lead to the electrical equipment shell of the equipment being electrified, which will cause harm to human safety.
Therefore, in the TN-S system, the neutral wire and the ground wire need to be grounded through the grounding electrode, so as to ensure that the human body will not be electrocuted.
In the TN-S system, the neutral wire and the ground wire have their own completely different functions, and the role of the ground wire is mainly to ground the electrical shell and prevent the electrical shell from being electrified, which will lead to harm to the human body.
The neutral line, on the other hand, is used to balance the unbalanced current in a three-phase power supply.
When balancing the three-phase power supply, the sum of the currents between any two phases of the power supply should be the current of the third-phase power supply, but in real life, the electrical appliances are not completely evenly distributed, resulting in the current not completely balanced when flowing, so this requires the neutral line to balance.
2. Why do we need a zero line?
When the electrical appliance is not completely evenly distributed, this will lead to a part of the current that cannot flow through the corresponding circuit in the process of electrical use, and this part of the current will be discharged through the grounding electrode, so it will lead to the phenomenon of electrification of the electrical shell.
When the human body comes into contact with the live electrical shell, it will cause the human body to be electrocuted, which will cause harm to human safety.
Therefore, in order to automatically trip the electrical appliance when the electrical shell is electrified, it is necessary to install a leakage protector on the electrical shell, and once the electrical shell is live, the leakage protector will automatically trip, so as to protect the human body from electric shock.
The leakage protector will also directly affect the service life of the electrical appliance, so in order to ensure the normal operation of the electrical appliance, it is necessary to pull another neutral wire to balance the electrical current, so as to ensure that the electrical shell will not be electrified.
In the power system, all kinds of lines are to ensure human safety and the normal operation of equipment, so so many lines are needed.
There will be an interrelated relationship between so many lines, and the failure of any line may affect the entire system, so the design of the power system will have a lot to consider.
Generally speaking, the design of the power system will take into account human safety, electrical equipment safety, circuit safety, and power quality, so the design of the power system will be very comprehensive and safe.
With the gradual increase of household electricity power, the safety and design requirements for the power system are also gradually improving, which also puts forward high requirements for the design and construction of the power system.
For the design and construction of the power system, it is necessary to carry out the construction in accordance with the specifications, so as to ensure that there will be no problems of electrical equipment safety and electricity safety when using electrical appliances.
At the same time, the maintenance and overhaul of the power system is also very important, which can carry out a comprehensive inspection and maintenance of the power system, so as to ensure the normal operation of the power system.
3. Why not use the zero line directly with the ground line.
Since the neutral wire and the ground wire have different functions, why can't they be replaced by ground wires?
This is mainly because the ground wire does not exist to balance the current of the appliance, so if the ground wire is directly used instead of the neutral wire, the electrical appliance will not be able to be used normally.
When an electrical appliance is not in normal use, it will have an impact on the appliance itself, and at the same time, it will also lead to a decrease in the efficiency of the electrical equipment, which will lead to an overload on the power system.
And when the electrical shell is electrified, the leakage protector will not be able to be used normally, which will have an impact on human safety, and when the human body is electrocuted, it may lead to electric shock accidents.
In addition, the ground wire also has a characteristic, that is, the ground wire is usually voltage-free, and when the voltage appears on the ground wire, this will lead to the phenomenon of step voltage.
When someone touches a live electrical shell, it will cause an electric current to flow through the human body because the human body is grounded, which will lead to the occurrence of electric shock accidents in the human body.
epilogue
Therefore, the neutral line and the ground wire in the power system are divided and cooperated, and only in this way can we better ensure the safety of electricity and the normal operation of equipment.
Therefore, when we use electrical appliances, we also need to pay attention to electrical safety, which is not only responsible for ourselves, but also responsible for others.
At the same time, the safety of the power system is also the foundation of social development and life security, which requires the joint efforts of the government, enterprises and individuals to strengthen management and publicity, so as to ensure the safety of electricity.