How to tell if there is a ground wire in a wall outlet

1. According to the current standard in China, when the third circuit in GB2681 is marked according to the color of the wire, it is phase wire - phase A yellow, phase B green, phase C red, zero line - light blue, and ground wire is yellow and green;

2. If it is a three-hole socket, the left side is the neutral wire, the middle is the ground wire, and the right side is the live wire;

3. The ground wire is the wire pulled out by the grounding device of the building, under normal circumstances, the ground wire is not passed by any current, and the metal shell of the electrical equipment connected to the ground wire does not have potential during normal operation.

A ground wire is a wire in an electrical system or electronic device that is connected to the ground, to the enclosure, or to a wire with a reference potential of zero.

There is a dedicated socket detector, about 10 more, shaped like a plug. The wiring method and wiring sequence can be detected including missing zero, missing ground, missing phase, etc., which is very practical and convenient. They are available in hardware stores.

Whether the ground wire is effective or not is related to our personal safety, so we must not be careless, and it is necessary for us to learn how to confirm whether the ground wire in our home is effective. The following is to share with you three common methods to detect whether the ground wire is effective. Therefore, in order to facilitate the judgment of the owner, a simple and intuitive detection method is recommended:

During the test, the ground wire is used instead of the live wire to see if the electricity can be used normally. (First of all, check whether the specifications of the ground wire of the sub-circuit are the same as the zero fire and the wire) The specific operation is as follows: with the development of high technology, the state is becoming more and more scientific in the management of residential electricity, and the normal residential household line has a single-phase three-wire system, ordinary people do not understand the principle here, but you can see the three-wire socket on the wall of your home, in accordance with the regulations of the power department.

Therefore, the role of the ground wire is very great, if the ground wire is invalid at home, it is relatively dangerous, and for the subject asked how to judge the socket ground wire is effective, today I will explain 3 ways to measure whether the ground wire grounding is effective, but the ground wire of home decoration can not be connected to the lightning cable, and each should take a line into the ground. Use the multimeter 250V gear to determine the jack of the zero line and the live wire, generally the three-hole plug is the left zero and the right fire on the ground, and measure the voltage difference between the live wire and the zero line, the live wire and the ground wire respectively, if the voltage difference between the fire wire and the ground is equal to the zero voltage difference between the fire wire.

From a professional point of view, it should be tested with a ground resistance tester, which is the most professional way to judge whether the ground wire is effective. This is related to the ground resistance value of the ground wire of the entire building or the entire area, and is generally measured by the power distribution or power supply personnel. One is; Use the multimeter AC voltage 250V to measure the voltage of the phase wire of each three-pole socket to the protective grounding wire, if the measured voltage is about 200V, it means that the protective grounding wire source is in line with the requirements (that is, effective).

To illustrate a point; Before measuring, try to measure whether the power supply voltage is normal. From a professional point of view, it should be tested with a ground resistance tester, which is the most professional way to judge whether the ground wire is effective. This is related to the ground resistance value of the ground wire of the entire building or the entire area, and is generally measured by the power distribution or power supply personnel.

First do a good job of the socket ground, and then plug in the switch to try it, you can judge whether it is effective.

The first way to detect the ground wire is to use the resistance of the multimeter to measure: we can use the function of the multimeter to measure the resistance of the line at home to detect the resistance of the wire at home, so as to judge whether the ground wire is effective; The testing requirement is that we choose a digital multimeter or mechanical multimeter with accurate measurement value, we must first remove the ground wire at home from the zero row, and then prepare a section of wire to connect the multimeter pen to use; The specific method is: we first adjust the range of the multimeter to the resistance level, remember the smallest resistance level; Then use the multimeter needle to connect one end to the ground wire removed in the distribution box, connect the other meter needle with a wire to the position that needs to be measured, and then touch the other end of the ground wire with the multimeter needle, observe the reading of the multimeter, if the reading is less than or equal to 4 or close to zero, then the ground wire is valid, if the reading is greater than 4, then the ground wire is invalid; Using the same method, we measure each ground wire in our home one by one, so that we can judge the condition of the ground wire.

The safest way is to use the resistance of a multimeter to measure whether it is valid or not.

To measure whether the grounding is good, you can use a bridge to test the ground wire hole of the socket or the resistance between the ground wire and the quasi-ground wire of electrical equipment. According to the national standard, the grounding resistance is less than or equal to 4 ohms. Quasi-ground:

Outdoor grounding piles. It can be found around the house. Find a load, such as a light bulb, the two wires are connected to the live wire and the ground wire hole respectively, if the bulb is not lit, and there is nothing abnormal in the distribution box, the ground wire does not exist or the ground wire is not really grounded; If the leakage circuit breaker trips immediately after the bulb is connected, the ground wire is normal.

If the bulb glows normally, there is a problem with the RCB, or there is no access to the RCB.

1。Measure the voltage of the live wire, the ground wire, and the neutral wire.

You can use the AC 250V file of the pointer meter or the Hongqiao AC 1000V file of the digital meter, first insert the red watch pen into the live wire jack, and then insert the black watch pen into the zero line (vice versa, the AC has no positive and negative poles), and see what the voltage value is at this time (about 220V); Then the red watch pen does not move, insert the black watch pen into the ground wire, such as the voltage value of the fight at this time is a few volts or the watch hand is only slightly biased, indicating that the power socket is not installed with a ground wire; If the voltage value is about 220V or the pointer has a very large deviation, it means that the power socket may be connected to the ground wire. Whether to install the ground wire depends on the test results of the second step, because if the protection in the power socket is connected to zero, this will also happen.

2。Measure the resistance between the neutral and ground wires.

In order to distinguish whether the power socket is "protected to zero", it is necessary to further judge the installation of the mains wiring. First cut off the home entrance wire, that is, break off all the leakage protectors and small circuit breakers in the current home. Then measure the resistance between the ground wire and the neutral wire with the 1 gear of the pointer meter or the conduction file of the digital meter, if the resistance value is very small or directly conductive, it means that the mains wiring uses the protection connection zero, and this connection needs to be canceled; If the resistance value is very large or not on, it means that the ground wire is correctly installed at home and can be used normally. :

1. Prepare the voltage tester that needs to be used for testing, we may not use the voltage tester often, so before using it, you need to test whether it is good, you can press and hold the metal part of the head and the last button at the end of the pen at the same time, if there is a small light on the electric pen, but there is nothing on the LCD screen, it means that the electric pen is good. 2. Test the live wire, that is, the phase wire, the small light will be very bright, and there is also a corresponding digital display on the LCD screen. 3. Test the zero line, at this time, the small light will be darker than when testing the live line, and there will be no digital display on the LCD screen.

4. The last is to test the ground wire, the effect is the same as the test zero line, if the ground wire is not wired according to the finger regulations, the small light will not be on.