2. Connection of grounding wire. The connection of ground wire includes the connection of our indoor upper end and the indoor end. The connection of the indoor upper end refers to the connection of the grounding wire in the indoor distribution box, which is connected with the grounding terminal block in the distribution box. The connection of indoor terminal grounding wire is connected with the grounding end of our socket. In addition, if it is necessary to connect lamps, it should be connected to the metal shell of lamps.
Principle of ground wire in household circuit
The basic principle of ground wire is to use the current in the circuit and take the loop with small resistance. The ground resistance of our home is basically less than 4Ω, and the resistance of our human body is basically between1500Ω and 2000Ω. Therefore, if there is leakage, then the leakage current must take a loop with small resistance, that is to say, it is directly introduced into the earth through the ground wire. Therefore, the human body is prevented from contacting the leakage current.
The function of ground wire in home circuit
The function of grounding wire is to protect the circuit. The ground wire is what we call PE, and its function is that when the circuit leaks, the leakage current can be quickly conducted to the ground through the earth. This avoids electric shock accidents caused by human contact with leakage current.
What is a ground wire?
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 to prevent electric shock accidents caused by insulation damage inside the shell. 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.
Ground wire classification
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. Safety grounding generally includes lightning protection grounding and electromagnetic radiation protection grounding.
1, working grounding:
Working grounding is a kind of grounding wire that embeds the copper block of metal conductor into the soil, then leads it out of the ground with wires, and uses it to complete the loop, so that the equipment can meet the performance requirements. Grounding wire requires grounding resistance ≤4ω. For example, in the 1960s and 1970s, every household in rural areas used a ground wire for broadcasting, and the ground wire was always wet by water.
2. Safe grounding:
The power regulations stipulate that the protective grounding resistance should be ≤ 4Ω, while the human body resistance is generally greater than 2000Ω. According to ohm's law, the current passing through human body when insulation is damaged is only 1/500 of the total current, thus playing a protective role. The metal shells of household appliances and office equipment are equipped with grounding wires. If the insulation of the shell is damaged and the shell is charged, the current will leak into the earth along the installed grounding wire to achieve the purpose of safety, otherwise it will cause harm to personal safety.
Lightning protection and grounding In order to prevent high-rise buildings, various communication systems, various antennas and other facilities installed on buildings from being struck by lightning in thunderstorm season, it is necessary to install lightning rods and then lead them to the installed lightning protection and grounding system with wires.
There is also anti-electromagnetic radiation grounding. In some important departments, in order to prevent electromagnetic interference, shielding nets are installed on electronic equipment, and the installed shielding nets should be connected to the corresponding grounding system, and the grounding resistance should be ≤ 4Ω.