In a three phase four wire circuit, is the ground wire connected to the neutral wire together?

As far as the user is concerned, regardless of the four-wire system or the five-wire system, the neutral line and the live wire are separated, and the neutral line (n) is the working circuit of the power supply, which is grounded from the neutral point of the transformer.

After the main line is drawn, there is an electric current passing through. The ground wire (PE) is not used in the working circuit, only as a protective ground wire.

It is the nearest grounding, when the three-phase load is unbalanced, there is generally a few volts of voltage between the neutral line and the live wire.

I think Yao Qilun is good.

You are a four-wire circuit, so the neutral line from the neutral point of the transformer is directly grounded, and it is also connected to you.

When the neutral wire is grounded, it is the neutral wire.

1. The neutral line is relative to the live wire, that is, the voltage of the live wire is relative to the zero voltage of the neutral line. The so-called relative refers to the voltage value of the terminal of the same name of the transformer to the tail of the coil, and the lead wire of the same name end is commonly known as the "live wire"; The lead-out wire at the end of the coil is commonly known as the "zero line".

2. The earth is equivalent to an infinite capacitor, with it as the reference point of the absolute zero point, the line drawn from the grounding electrode is commonly known as the "ground wire", its function is to provide a reference of the absolute zero point, and at the same time provide a container to accommodate infinite current.

3. The advantage of sharing (connecting) the zero point with the ground wire is: the live wire voltage is an absolute voltage, which is an absolute voltage for a small capacity electrical appliance or transformer coil, when the single-phase open circuit, the star point is the absolute voltage and the voltage value of the other two phases cannot drift; Secondly, when the insulation is damaged, a large short-circuit current can be generated, which promotes the protective quick break of the switch.

4. Different from the European "three-phase five-wire", China's "three-phase four-wire", the zero potential of the electrical voltage of the equipment and the zero potential of the equipment protection is a potential, and a large enough trip short-circuit current will be generated when the leakage is leakage. The "three-phase five-wire" will not, only timed tripping will occur when leakage, and the neutral line will produce a large voltage (zero drift) when the phase is broken. In this case, the extent of the accident is sometimes expanded.

Yes, it works.

The three-phase five-wire power supply is the power supply of the TN-S system. The power supply of the TN-S system is a system in which the working neutral line and the protection neutral line are separated. The system works with the neutral and protection neutrals connected together at the neutral point of the transformer. So the neutral and ground wires are connected.

In addition to the three live wires, one is a zero-ground PEN wire, and the neutral wire is grounded at intervals in the pull wire to keep it potential. When entering the house, it is necessary to ground again, and after entering the home, it is divided into protective ground wire (PE) and neutral line (N), which can not be closed at this time, but because the zero ground wire is not allowed to be disconnected, it should still be on when measuring.

The ground wire is not the same as the zero line, it cannot be replaced, the ground wire connects the earth, the symbol is e, the zero line is the middle line, the symbol is n, and it cannot be mixed.

The ground wire can not be used as a neutral wire, because the ground wire has a protective effect and does not flow through the current when used, so that when there is a leakage of electrical appliances, the current can flow to the ground to avoid the occurrence of human electric shock accidents.

The neutral wire in the power supply line is allowed to be generated in a regular grounding manner, and it is allowed to share a grounding device with the ground wire. However, the ground wire and the neutral wire shall not be connected to each other except for the grounding point, let alone mixed.

Not universal, the three-phase five-wire system is actually two wires drawn from the neutral point of the transformer, one as the working neutral line and the other as the protection neutral line (it is inaccurate to say that the ground wire). Normally, there is a current flow in the working zero line, and there is no current flow in the protection zero line, only the electrical equipment line insulation is damaged, and the protection zero line has a current flow when it touches the shell, and the power supply is cut off through the action of the set relay protection device to protect personal safety. In the same system, it is strictly forbidden to mix protection zero and protection grounding, because when the equipment grounded by the shell leaks, and the accident current caused by the fuse burns, the equipment shell will be charged 110V, and the potential of the entire zero line to the ground will be increased to 110V, so the shell of other zero connection equipment has a potential of 110V to the ground, which is very dangerous.

Therefore, it is not allowed to adopt the mixed practice of zero connection of part of the equipment and grounding of part of the equipment on the same system. Even if the fuse meets the requirements of being able to burn, the mixed connection method is not allowed. Because the fuse is often replaced in use, it is difficult to ensure that there will be no errors.

The neutral point of the low-voltage side of the distribution transformer in China is directly grounded, which is called the power supply O point. From the neutral point of the grounding respectively lead out two insulated wires, one is the neutral line (N line), the other PE wire, these two wires are connected together in addition to the neutral point of the transformer, after all the way to the end of the load, must be well insulated, no longer electrical connection is allowed, so the voltage on the PE line to the ground is always zero, there is always no current flowing, its function is to protect personnel from electric shock, protect the safety of people. A, B, C three-phase plus N, PE line, it becomes a three-phase five-wire.

In the one-phase four-wire power system, the neutral line grounding will not have an impact, and for safety, the neutral line needs to be repeatedly grounded in many cases.

Second, the role of the zero line in the three-phase four-wire system:

In the three-phase four-wire low-voltage power supply system, the function of the neutral line is to ensure that the potential of the neutral line is zero when the three-phase load is asymmetrical, so as to eliminate the change of neutral potential and keep the voltage of each phase symmetrical, that is, the phase voltage of each phase load is always equal to the phase voltage of the power supply, and has nothing to do with the load change.

3. The impact of zero line disconnection in the three-phase four-wire system:

1. If one of the three phases is broken, it will only affect the phase, and the voltage of the other two phases remains unchanged, and the electrical equipment connected to the two phases can still work normally.

2. Once the neutral line in the three-phase four-wire system is broken for some reason, in the case of asymmetrical three-phase load, the neutral point displacement will occur, resulting in the three-phase voltage imbalance, and some phase voltages are too high, which may burn the electrical equipment; Some phase voltages are too low, and electrical equipment cannot be used normally.

In the three-phase five-wire system, what are the consequences of only connecting the ground wire without connecting the neutral wire, or only connecting the zero wire without the ground wire?

In the three-phase five-wire system, what are the consequences of only connecting the ground wire without connecting the neutral wire, or only connecting the zero wire without the ground wire? It is not possible to connect the zero line. There are requirements for various design specifications, such as GB50054, which clearly requires that the zero line cannot be broken, which is a mandatory standard.

If the ground wire is not grounded, that is, the PE wire, it will cause the electrical equipment to be unsafe.

How many volts V is there between the neutral and ground voltages? If the voltage is the same as the live wire, the zero line is broken. The neutral voltage is not too high, which is caused by three-phase unbalance or harmonics. Installing a zero-ground voltage treatment device is sufficient.

What is the measured voltage of the opposite strip?

When measuring to the ground with a multimeter, the neutral wire and the ground wire are 220 volts, and the ground wire and the neutral wire are disconnected.

If the voltage measured with a digital pen is less than 220 volts, it cannot be used as a basis for being electrified.

This phenomenon occurs only when the zero ground wire is poorly contacted.

It is the poor grounding of the transformer grounding point.

No. 1. Unsafe.

2. The leakage protector will trip.

<> three blocking phase four lines are TN-C system, and the neutral line N and the protection line PE are combined into one silver. Fengheng Mountain.