The ground wire is a way of grounding our electricity. It is also commonly used as a protective earth.
Grounding is a good contact between the equipment and the earth.
Protective grounding, that is, the electrical equipment in the event of a fault may be dangerous to the ground voltage of the metal parts (such as the shell, etc.) with a wire and the earth to make an electrical connection.
If there is no protective grounding of electrical equipment, when a part of the insulation is damaged, the shell will be charged, and because of the capacitance between the line and the earth, the human body touches the insulation damage to the shell of the electrical equipment will be subjected to the risk of electric shock. The implementation of protective grounding of electrical equipment, grounding short-circuit current will be along the grounding body and the human body through two paths. Ground resistance is generally 4 ohms or less, and the human body resistance of about 1000 ohms, so through the grounding body shunt effect, the current flowing through the human body is almost equal to zero, which avoids the risk of electrocution in the short-circuit fault current of the human body.
Protective grounding can play the following roles:
(1) to provide low impedance connection between the equipment and the near metal objects to reduce the risk of personal electric shock;
(2) to provide a low impedance path for the return of ground fault current to the power supply, so that the fuse or circuit breaker can be operated;
(3) to provide a low impedance path for the lightning induced current to the ground to discharge;
(3) to the lightning induced current to the ground to provide low impedance path.
(4) Provide an earth discharge path for static charges to prevent sparking or arcing.
Question 2: What is the role of the ground line The ground line can make the electrical conductive exposed part and the earth connected to the formation of the potential, so that even if the shell of the appliance leakage, the current will flow through the ground line to the earth, thus preventing the human body from being electrocuted. In addition, the lightning rod also through the grounding wire and grounding device will be the lightning current into the earth.
Question 3: What is the role of the grounding wire? What are the consequences of not grounded The role of the grounding wire is to avoid the occurrence of household leakage injury to the human body and connected; the possibility of electrified metal casing on the electricity to the earth, so as to avoid people touching the occurrence of electrocution accidents. If not grounded, once the equipment leakage phenomenon, the person touches the charged body, there may be electrocution.
Household electric grounding line is to protect personal safety, to prevent household appliances leakage after personal electric shock, note that the grounding line can not prevent lightning.
The neutral wire should be grounded in order to improve the safety of the power supply, so that the voltage of each phase line to the ground does not exceed 220 V. If the neutral wire is not grounded, when one of the phase line is disconnected and falls to the ground, the voltage of the other two phase lines to the ground is equal to the value of the line voltage, that is, 380 volts, which is more dangerous.
In daily life will often use electrical appliances not charged metal part of the grounding, called protective grounding. Three-eye socket for fans with this grounding, once the insulation of electrical equipment somewhere damaged, the metal shell of the charge will appear directly through the grounding wire into the earth, so that the metal shell to ground voltage is nearly zero, to avoid the risk of electric shock. When a phase of the wire and metal casing short circuit, the current will be directly to the ground.
The grounded neutral line is also known as the zero line, in some electrical equipment, in order to make the protective device reliable action, often the shell of the appliance connected to the zero line, which is called protective zero. The advantage of zero is to touch the shell into a single-phase short circuit, resulting in a large current, so that circuit protection equipment such as fuses can be reliable and rapid action to break the circuit to protect the faulty equipment.
But this zero can not replace the role of protective grounding. If we connect the ground terminal of the three-eye socket with the zero wire, when the light switch is closed, or the appliance is connected to the three-wire socket, 220V voltage will pass through the filament or the appliance internal wires to make the shell charged. If the neutral fuse is broken, the light may not be on, but the phase wire can still be connected to the shell of the appliance through the filament, causing danger.
Leakage without a ground wire can cause injury or death.
Question 4: What is the role of the ground wire? Electrical appliances have a zero wire and fire wire, thus constituting a pathway, so that the electrical appliances have a current through the role of the switch is closed, the zero wire is not charged.
The ground wire is not charged whether the switch is off or not, and its main function is the grounding you mentioned. In order to avoid the occurrence of leakage accidents, or strong electric potential may be harmful to people, high-power electrical appliances have a ground wire, can be generated by the excess current or strong electric potential through the ground wire into the earth.
The ground wire cannot function properly if it is not connected, and is a setting that exists for the safety of the user.
Question 5: What is the purpose and function of grounding? The purpose of grounding:
1, in the power system, the grounding required for operation, such as neutral grounding, etc., known as work grounding.
2, the metal casing of electrical equipment, reinforced concrete poles and metal towers, etc., due to insulation damage may be electrically charged, in order to prevent this voltage jeopardizes the safety of the person and the grounding, known as protective grounding. Protective grounding is not grounded in the neutral point of the low-voltage distribution system and high-voltage power systems, electrical equipment and electrical lines most used in a security measure.
3, grounded voltage protection devices, such as lightning rods, lightning arrester and security gap, in order to eliminate the risk of overvoltage and grounding, known as overvoltage protection grounding.
4, easy fuel, natural gas storage tanks and pipelines, etc., in order to prevent the impact of electrostatic hazards and grounding, known as anti-static grounding.
The role of grounding:
1. To prevent electromagnetic coupling interference: such as digital equipment grounding; RF cable wiring shield grounding, etc.;
2. To prevent strong electricity and lightning strikes on communications equipment: such as columns of racks and general communications equipment chassis grounding, to prevent equipment, instrumentation, personal injury;
3. Communication system needs: such as the remote supply of submarine cable relay equipment. System using wire - earth system way.
Question 6: What is the role of the FireWire, ZeroWire, GroundWire? The role of the firewire is: into the power supply. Zero line role: auxiliary composition back. The role of the ground: to prevent leakage of electricity after injury to the operator. Ground can not be mixed with the zero line. In some special occasions zero ground can also be mixed.
Question 7: What is the role of the ground line How to play a protective role This is previously seen on the Internet, the feeling that this is the most clear, so together **** enjoy!
The factory, generally three-phase power, the three lines are usually said to be the firewire, they come out of the power supply transformer, transmitted to the user units, such as three-phase asynchronous motors can be used directly, but the three lines of electricity in the phase is not the same, that is, the waveforms are dislocated (the knowledge of this should be possible to learn in the high school stage), theoretically, the three wires are connected to the same time (the neutral point) Theoretically, when the three wires are connected together (neutral), there should be zero voltage. Sometimes the voltage in these three lines due to the power consumption of the three lines, resulting in three neutral point voltage is not 0, theoretically 0 potential, then we need to add a center line line, or zero line, the voltage is not 0 to return to the power supply transformer. This creates a three-phase 4-wire. At the same time, sometimes for safety reasons, there are many units and increase the ground line, the outer surface of the motor ground, near the power supply transformer to do a grounding stake and the ground line into a whole, so the ground line is interconnected with the earth. This makes three-phase five-wire. The same ground wire connected to the earth, when the motor due to faults to make its shell charged, if there is no ground case will be charged, with the ground connected to the motor shell will not be charged!
The three wires used in the home and industry are not the same, the home is one of the three-phase wires described above, and then equipped with a zero line and ground, the zero line is the current through the electrical appliances and send the current back to the power supply transformer to form a loop. Ground is to prevent leakage after the insulation of the firewire is aged, resulting in the appearance of electrical appliances charged, prone to electrocution, grounding, then the earth's potential is 0, so that the potential of the appearance of the electricity and the earth to maintain the same, reducing the leakage of electricity after the occurrence of electrocution accident chances.
Question 8: Why is there a ground wire on the socket, what role does the ground wire play? The role of the ground has three, one is when the leakage of electricity in case of electric shock can reduce the voltage of electric shock, the second role is the use of switchgear is generally leakage protector, when the leakage of electric current through the ground trip circuit, not through the protector of the zero-sequence current transformer, so that the leakage of current is detected, the protector action automatically disconnect, three is if you use the air switch, you can increase the short-circuit current, resulting in the air open Action disconnect. Simply put, it is to prevent the expansion of electrocution hazards.