How to confirm the zero line of the ground wire with an electric pen?
1. When powered on and measured with an electric pen, the live wire will light up.
2. Disconnect the zero wire, only connect the live wire, turn the home light on, measure with an electric pen, and the other one that will light up is the zero wire.
3. The rest is the ground wire.
Direct use of zero and ground wires
Electric pens cannot be measured, they are not charged to the ground, so even test pens will not light up. The live wire can be tested with an electric test pen.
In the case of residual current protection devices (leakage circuit breakers), it is possible to distinguish between the live and zero lines through experiments. A light bulb is connected between the live and zero lines, and the light bulb emits normal light. However, a light bulb is connected between the live and ground lines, and the leakage circuit breaker will immediately trip.
Household electricity is generally single-phase electricity of 220V~250V, which is formed by the live wire passing through the load, such as a light bulb, and then passing through the zero wire to form a circuit for the electrical appliance to work normally. Some electrical appliances with metal shells also need to be connected to a grounding wire, which can be led to the ground in case of accidental electrification of the electrical shell, ensuring electrical safety.
In the wiring arrangement and daily maintenance, different colored wires are generally used to distinguish wires for different purposes.
Hot wire generally uses warm colored wire, with the most common being red wire. If pursuing more standardized construction, different colored live wires can be used to distinguish different circuits. In addition to the red line, yellow and green lines can also be used. However, distinguishing between multiple colored wires will to some extent increase the cost of wire procurement.
The zero line generally adopts a cold colored line, with the most common being a blue line, and some also use a black line.
According to the standard, grounding wires can only be used with yellow and green alternating colors. Due to the importance of grounding wires for electrical safety, their color requirements are very strict and cannot be replaced by wires of other colors.
Sort by color
Red live wire, blue zero wire, yellow green dual color ground wire
If the colors cannot be distinguished
In practical applications, I will give you three wires, one is a live wire, one is a zero wire, and one is a ground wire. If the colors of the three wires are the same! How can you distinguish?
1. The correct connection method is: the phase line (L) is generally red or brown; The zero line (N) is blue or green in color; The color of the protective ground wire (PE) must be yellow and green
2. Can you use a clamp type ammeter to measure the live wire with an electric pen? The current of the phase wire (live wire) and the zero wire is the same, and there is no current when the ground wire is normal.
3. The zero line has current flowing through it; The ground wire is used for protection, and there is no current during normal operation. Only when there is a short circuit or leakage, there is current. The grounding resistance is required to be very small, and the equipment end is generally grounded by the protective shell.
Use an electric pen to measure the live wire, and place the test light (with a wire bulb) on one of the live wires and the other two wires. If the light is on, it indicates that it is a 0 wire. If the light is on or off. It indicates that it is a ground wire. (The lamp test method is effective when the ground wire is not connected to the ground. If the ground wire is connected to the ground, the lamp will light up regardless of which line it is connected to.)
4. In the presence of a power source, it should not be difficult to find the live wire. The difficulty lies in distinguishing between the zero wire and the ground wire. In theory, the voltage between the live wire and the zero wire is 220 to the right, and the voltage between the live wire and the ground wire is about 190 volts. If you connect an energy-saving lamp, the brightness should be visible, and the bright one is naturally the zero line, for reference only.
5. There's another simple way
We use a test light (with a wire bulb) to connect it to one of the live wire and the other two wires. If the light is on, it indicates that it is a 0 wire. If the light comes on, the leakage switch will trip. It indicates that it is a ground wire.
