How to measure whether the ground wire is well grounded
There are three ways to measure whether the ground wire is in good contact:
1. Multimeter measurement, multimeter is also called multimeter, multimeter, three-meter, multimeter, etc. It is an indispensable measuring instrument in power electronics and other departments, and its main purpose is to measure voltage, current and resistance.
How to use: When measuring, turn the gear knob to select the correct gear (250V~). After that, insert the black test lead into the COM jack, and the red test lead into the jack marked "V". Hold the watch in one hand, and hold the two test leads in the other hand like chopsticks—you can only hold the plastic rod, and you can’t touch the wire, let alone the metal at the front end. Touch the two test leads to the two lines to be tested respectively.
Judgment method: The voltage between the zero and live wires is the same as or slightly greater than the voltage on the ground and live wires (not exceeding 5V), which proves that the ground wire is well grounded, and the smaller the difference between the two, the smaller the grounding resistance. On the contrary, the grounding body is faulty.
2. To measure the light bulb, you need to deal with the light bulb in advance and connect two wires for later operation - if there is an idle light socket, you can directly install the light bulb on the light socket, and then connect the light bulb to the neutral line and the Between the live wire, the ground wire and the live wire (remember to cut off the power when wiring), observe the brightness of the bulb, and analyze the results.
With the ground wire well grounded, the bulb will be the same brightness twice. If the ground body fails, the bulb will not light. If it's just a slightly higher resistance to ground, then the bulb is only slightly dimmer.
3. Ground resistance tester, generally speaking, this equipment will be used for testing during project acceptance. The ground resistance tester can accurately measure the ground resistance of the ground wire. Generally, the ground wire used in our home is qualified as long as the grounding resistance is not greater than 4 ohms.
Basic functions of the multimeter:
1. Measurement: resistance, AC and DC voltage, AC and DC current, on-off.
2. Expansion: capacitor, inductor, diode, triode.
The multimeter has the advantages of multi-purpose, wide range, and convenient use. It is the most commonly used tool in electronic measurement. It can be used to measure resistance, AC-DC voltage and DC voltage. Some multimeters can also measure the main parameters of transistors and the capacitance of capacitors. Mastering the use of multimeters is a basic skill in electronic technology.
3. Common multimeters include pointer multimeters and digital multimeters. The pointer multimeter is a multi-functional measuring instrument with the meter head as the core component, and the measured value is read by the pointer of the meter head. The measured value of the digital multimeter is directly displayed in digital form by the liquid crystal display, which is easy to read, and some also have a voice prompt function.
4. The DC current file of the multimeter is a multi-range DC voltmeter. The voltage range can be expanded by connecting the closed-circuit voltage dividing resistor in parallel with the meter head. The DC voltage file of the multimeter is a multi-range DC voltmeter. Connecting the voltage dividing resistor in series with the meter head can expand its voltage range. Different voltage dividing resistors have different corresponding measuring ranges.
