A live wire is a power line that carries current in a circuit. The zero line is the line drawn from the neutral point of the secondary side of the transformer, which forms a loop with the phase line to supply power to the electrical equipment.
1. Color: In power cables, yellow, green and red respectively represent phase A, phase B and phase C, blue represents zero line, and yellow and green represents grounding line.
2. Distinguish with an electric pen: When testing the live wire with an electric pen, the neon tube will glow, but the zero line will not.
3. Use voltmeter to distinguish: the voltage between different phase lines is 380V, the voltage between phase line and neutral line is 220V, and the voltage between neutral line and good grounding body is 0 V. ..
Contact between live wire and neutral wire.
Because the voltage between them is equal to 220 volts, the resistance between the two contact points is almost equal to zero. At this time, the current is very large, and the contact point between the live wire and the neutral wire will generate huge heat, thus generating sparks. The temperature at the spark is high enough to melt the metal wire. If the human body touches the live line and the neutral line at the same time, it will get an electric shock regardless of whether it touches the ground at the same time.
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What are three-phase electricity, live wire, neutral wire and ground wire respectively?
Answer: Three-phase electricity, live wire, neutral wire and ground wire are respectively
1, the full name of three-phase electricity is three-phase AC power supply, which is a transmission form of electric energy and consists of three AC potentials with the same frequency, equal amplitude and phase difference of 120.
L-fire line, N-zero line, G-ground line. Usually red is the fire line, blue is the zero line, and bicolor is the ground line.
2. The live wire is the power line that transmits power in the circuit.
3, zero line, mainly used in the working circuit, from the transformer neutral grounding leads to the trunk line.
4. The grounding wire is a wire connected to the earth, shell or zero reference potential in an electrical system or electronic equipment. In general electrical appliances, the ground wire is connected to the shell in order to prevent the internal insulation of the shell from being damaged and charged, resulting in electric shock accidents. Ground wire is short for grounding device. Grounding wire is divided into working grounding and safety grounding. In order to prevent people from getting an electric shock when using household appliances, office and other electronic equipment, protective grounding is a kind of safe grounding wire.
How to distinguish between ground wire, neutral wire and live wire
Ground wire, neutral wire and live wire can be distinguished from the following aspects:
1, color-sensitive
Firewire: Red, yellow and green must be used.
Zero line: black and blue must be used.
Grounding wire: yellow-green double-color wire is required.
This method is for reference only. The red one is not necessarily the fire line, because many electricians don't use wires according to the standard.
2, can be judged by three hole socket. The neutral wire is connected to the left, the live wire is connected to the right, and the ground wire is connected to the middle.
3. Test with a charged pen. Put the electric pen on the socket, high voltage is the live wire, low voltage is the zero line, and almost no voltage is the ground wire.
4, digital recognition differences
According to the line number or the mark on the drawing, according to the national standard, the general trunk line cores are 1, No.2 and No.3, such as three-phase lines; 0 is used for neutral cores, such as neutral wires; Of the 5 cores, 4 cores are used for grounding wire.
5, use a multimeter to identify
Before measurement, cut off the power supply, put the live wire, zero wire and ground wire in the air, pull them apart, and then turn on the power supply. Then turn the multimeter to 500V, just touch three wires with an iron pen, the maximum value is live wire, the minimum value is ground wire, and the middle one is zero wire.
What are the differences and functions of live wire, neutral wire and ground wire?
Two wires in the lighting circuit, one is called live wire, which is the power supply line for transmitting power in the circuit; One is called zero line, which is a line drawn from the neutral point of the secondary side of the generator or transformer, and forms a loop with the phase line to supply power to the electrical equipment.
Under normal circumstances, the zero line is repeatedly grounded with the protective ground wire at the neutral point of the secondary side of the transformer, which plays a double protection role.
Grounding wire is a wire connected to the earth, shell or zero reference potential in electrical system or electronic equipment. In general electrical appliances, the ground wire is connected to the shell in order to prevent the internal insulation of the shell from being damaged and charged, resulting in electric shock accidents.
Difference:
1. Color: In power cables, yellow, green and red respectively represent phase A, phase B and phase C, blue represents zero line, and yellow and green represents grounding line.
2. Distinguish with an electric pen: When testing the live wire with an electric pen, the neon tube will glow, but the zero line will not.
3. Use voltmeter to distinguish: the voltage between different phase lines is 380V, the voltage between phase line and neutral line is 220V, and the voltage between neutral line and good grounding body is 0 V. ..
Matters needing attention in power connection
First, prevent electric shock and short circuit;
Second, pay attention to the switch to control the fire line;
Third, it is best not to connect the fuse to the zero line;
Fourthly, the central part of the lamp holder is connected with the live wire;
5. Don't mix ground wire and zero wire;
6. Disconnect the live wire with electrical appliances, so that contact with electrical appliances will not get an electric shock. If the neutral line is broken, people will get an electric shock.