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, also known as multi-meter, multi-meter, three-meter, multi-meter, etc., is an indispensable measuring instrument in power electronics and other departments, generally for measuring voltage, current and resistance.
Usage: When measuring, rotate the gear knob to select the correct gear (250V~). After that, insert the black stylus into the COM jack and the red stylus into the jack marked "V". One hand holds a watch, and the other hand holds two pens like chopsticks-only plastic sticks, not wires, and not front metal. Touch two probes to two lines to be measured respectively.
Judgment method: The voltage between the zero live wire is the same as or slightly larger than the voltage on the ground wire and live wire (less than 5V), which proves that the ground wire is well grounded, and the smaller the difference between them, the smaller the grounding resistance. Otherwise, the grounding body fails.
2, light bulb measurement, to deal with the light bulb in advance, take out 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 between the zero line and the live line, the ground line and the live line respectively (remember to cut off the power when wiring), observe the brightness of the light bulb and analyze the results.
When the ground wire is well grounded, the twice brightness of the bulb is the same. If the grounding body fails, the light bulb will not light up. If only the grounding resistance is slightly larger, then the light bulb is only slightly dimmed.
3, grounding resistance tester, generally speaking, in the project acceptance, will use this equipment for testing. The grounding resistance tester can accurately measure the grounding resistance of the ground wire. Generally, the grounding wire used in our family is qualified as long as the grounding resistance is not more than 4 ohms.
Extended data:
Basic functions of multimeter:
1. Measurement: AC/DC voltage and AC/DC current of resistance are on and off.
2. Expansion: capacitor inductor diode triode.
Multimeter has many advantages, such as 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 user of multimeter is a basic skill of electronic technology.
3. Common multimeters include pointer multimeter and digital multimeter. The pointer multimeter is a multifunctional measuring instrument with the meter head as the core component, and the measured value is read by the pointer on the meter head. The measured values of digital multimeter are displayed directly in digital form by LCD screen, which is convenient to read, and some of them also have voice prompt function.
4. The DC current file of multimeter is a multi-range DC voltmeter. The voltage range of the meter can be expanded by connecting the closed-circuit voltage divider in parallel. The DC voltage range of multimeter is a multi-range DC voltmeter. The voltage range of the meter can be expanded by connecting the voltage divider resistor in series. Different voltage dividing resistors have different corresponding ranges.
