Under what circumstances will there be 220 V between neutral line and ground line?
The three ends of live wire, neutral wire and ground wire are called phase wires, and three ends of three-phase electricity are connected together and are called neutral wires, also called "neutral wires". The reason it is called neutral line is because there is no current in neutral line during three-phase balance, and it is directly or indirectly connected to ground, and voltage to ground is close to zero.
Typically, live wires in a three-phase circuit are marked red, yellow, and blue to represent three live wires, and neutral wire is black. In a single-phase lighting circuit, typically yellow is live wire, blue is neutral wire, and yellow and green are ground wire. In some places, red is used for live wire, black for neutral wire, and yellow and green for ground wire.
My country's existing power supply system uses a three-phase four-wire system, and power is also divided into industrial power and civil power.
Industrial electricity: there are three live wires, voltage between them is ~380V, and phase difference of each phase is 120 degrees.
Civilian electricity: there are live wires, neutral wires and ground wires, and voltage between them is ~220V.
Electrical appliances have a neutral wire and a live wire that form a path so that electrical appliance passes through current and plays a role. When switch is off, neutral wire is not charged.
The ground wire is not charged whether switch is closed or not, and its main function is said ground. In order to avoid leakage accidents or possible harm to people by high electrical potential, high-power electrical appliances have an earth wire that can drain excess current or strong electrical potential generated to earth through earth wire.
A ground wire is a line that securely connects body of equipment or electrical appliances to earth and is a good solution to prevent electric shock accidents. If ground wire is not connected properly, it may not work properly. This setting exists for safety of users.
In everyday life, ground wire is connected to ground and at same time connected to housing of household appliances; neutral wire is also connected to ground, so in theory there is no voltage between neutral wire. and ground wire. Under what circumstances will there be 220 V between neutral line and ground line?
1. Due to external force, line is damaged due to external force and other reasons.
2. Construction quality, due to poor construction technology, poor contact will lead to heating, causing neutral line to be cut off. At this time, power supply will pass through N line through electrical appliances.
3. Installing a ground wire is unreliable, and an unreliable ground wire leads to high resistance. When a live wire touches a ground wire, it means that ground wire is a live wire. At this time, there will be voltage between neutral wire and ground wire.
4. The neutral wire is disconnected, and live wire and load, such as light bulb and neutral wire, are at same potential. At this time, there will be voltage between neutral wire and the ground wire.
5. The neutral wire and live wire are reversed.
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