Three-phase alternating current is a combination of three alternating currents, with the same frequency, but the phases are offset by 120 degrees.
The voltage between the live wire and the neutral wire is called the phase voltage (between the live wire and the neutral wire).
The voltage between the two live wires is called the line voltage (between the live wires).
In our daily circuits in China, the phase voltage is 220V and the line voltage is 380V.
Generally, red is the live wire, blue is the neutral wire, and black is the ground wire.
The difference between the live wire and the neutral wire
Both the live wire and the neutral wire are live wires. If a two-phase power supply is connected to an appliance, then there will be current flowing through the wire.
Generally, the live wire is perceived as carrying electricity because if a person touches (including some indirect contact) the live wire, a portion of the current will pass through the person’s body, just like a water pipe with a faucet in the middle. The neutral wire is not electrified because the other end of the power supply (the neutral wire) is connected to the ground. When we touch the neutral wire on the ground, since there is no potential difference, no current will be formed. So there is a feeling that the neutral wire is not electrified. The neutral wire and the live wire are originally both coming from the power supply, and the current flows in the positive direction from one end, through external equipment, and into the other end, forming a circuit. The difference between the neutral wire and the live wire is that one of the two terminals of the power supply is connected to the ground.
The difference between the neutral wire and the ground wire
1. The neutral wire and the ground wire are two different concepts, not the same thing.
2. The ground wire has a ground potential of zero. Electrical appliances are grounded at the nearest point.
3. The ground potential of the neutral wire is not necessarily zero. The nearest connection point of the neutral wire is at the substation or the transformer of the power supply.
4. Sometimes the neutral wire can electrocute a person. When? When your electric stove stops heating, don’t think it’s out of power. Wrong! There might be such a possibility. If the N wire is disconnected at a distance from your appliance, when you measure with a voltmeter, you will find that the LN wire of the appliance is the voltage of the mains electricity!
5. The ground wire will not electrocute a person, unless in a very bad situation, the designer doesn’t understand, or the product is randomly made!
6. If there is a neutral wire and a ground wire in your circuit, you will find a high-voltage capacitor between them.
Post time: Nov-27-2025
