A grounding wire is a circuit that is connected to the casing of electrical equipment and other parts, and timely exports unsafe charges or leakage currents generated due to various reasons. It is a life-saving wire at critical moments But if there is a problem with the grounding wire and it cannot provide protection, the life-saving wire will be switched to a life-saving wire every minute. Therefore, as an electrician who often deals with wires, it is necessary to learn to judge whether the grounding wire is effective
The following three methods can help electricians determine whether the grounding wire is effective!
1. Measure with a multimeter
Set the multimeter to 250V and measure the voltage between the zero and live wires, as well as between the ground and live wires.
. If the voltage between the zero line and the live line is 220V, it proves that the voltage is normal At this point, if the voltage between the ground wire and the live wire is the same or slightly higher (not exceeding 5V) as the voltage between the zero wire and the live wire, it indicates that the ground wire is well grounded, and the smaller the difference between the two, the smaller the grounding resistance If the voltage between the ground wire and the live wire is less than 200V, it indicates poor grounding; If the voltage is zero or only a few tens of volts, grounding is invalid2. Bulb measurement
Generally, a multimeter is used for measurement, but if there is no multimeter in hand, a bulb can also be used to measure the grounding situation.
Connect the light bulb to the zero and live wires, as well as the ground and live wires, and observe the brightness of the light bulb If the brightness of the bulb is the same twice, it indicates that the ground wire is well grounded; If the brightness of the ground wire and live wire bulbs is lower than that of the zero wire and live wire bulbs, it indicates poor grounding of the ground wire; If the bulb does not light up, it indicates that the grounding wire is invalid3. Grounding Resistance Tester
Grounding Resistance Tester can accurately measure the grounding resistance of the grounding wire. However, due to its high cost, it is generally used during engineering acceptance.
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