The zero ground voltage is the voltage on the zero line n, which can also be described as the potential difference between the zero line n and the ground line pe.
Because under normal circumstances the ground is zero voltage, so the zero-ground voltage is the voltage on the zero line is also shown in the figure below Upen. Upen = In * Rn, In is the current flowing through the zero line, Rn is the resistance value of the zero line.
The commonly used TN-S system (that is, the original three-phase five-wire) is the work of the zero line N and ground PE strictly separate power supply system, the user side of the zero line in general is not allowed to short again.
Send the circuit by the proximity of the decision of the length of the zero line, in the case of the zero line cross-sectional area remains unchanged, the length of the zero line also determines the size of the zero line resistance value. There is resistance on the zero line, and once a current passes through the zero line, the zero ground voltage is generated.
Expanded Information
To ground voltage, electrical equipment ground faults, grounded equipment, grounding equipment, grounding wire, grounding body is equal to the zero potential point of potential difference between the points, known as the electrical equipment grounded to ground voltage.
In the power system, the ground voltage refers to the occurrence of ground faults in electrical equipment, grounding equipment shell, grounding wire, grounding body is equal to the zero potential point between the potential difference. The earth is usually set as the zero potential point.
Voltage has a positive and negative points, the earth as the zero point of potential, +220v voltage to ground, that is, the voltage of the zero point, the difference between them is 220v.
The zero line is the ground, seen as the same as the earth , so it is the 0v firewire is the high voltage line in the home, our country is the 220v, some countries have different standards. Light hand touching the fire wire theoretically will not be electrocuted, because there is no conduction.
So there is no charge to move the fuse line radius the larger the resistance is smaller, the heat of the burn is the square of the current multiplied by the resistance and the value of time, assuming that the same amount of heat in order to burn the fuse, the resistance of the smaller, the current required to be larger.
Reference:
Baidu Encyclopedia - Low Voltage
Reference:
Reference:
Baidu Encyclopedia - Zero Ground Voltage