Have you ever been electrocuted? 5 tips to distinguish between induction electricity and leakage electricity

In daily life, when household appliances (such as washing machines, refrigerators, power tools) leak electricity or are induced to be charged, you will feel a "numbness" in your hands. If you use a test pen to test, both will make the neon bulb of the test pen turn red. So how can you distinguish them?

First, let's talk about the causes of leakage or induction. Induction charging is caused by the mutual induction between the internal circuit and the outer shell of the machine or between the circuits, which is equivalent to the connection between the charged part and the outer shell through capacitance. Leakage is caused by the aging or reduction of the insulation of the internal circuit due to the long-term use of the machine or moisture, which makes the outer shell of the machine charged.

Essential Difference

Induced electricity or static electricity usually takes a while to accumulate a certain voltage after being discharged; leakage electricity is generated from a continuous power source and is continuous.

1. The static shock lasts only for a moment. When you touch the washing machine again, you will not feel it. You have to wait for a while before you can feel the static shock again. Static electricity can be judged with a stylus pen. Take the washing machine as an example. The method is: after the washing machine runs for a while, bring the stylus pen close to the detergent. You will hear a "pop" sound and see the spark of discharge.

2. Leakage is caused by a certain potential difference between the electrical housing and the live wire of the mains and the ground. The best way to detect leakage is to touch the charged body with a test pen. If the neon bulb lights up and then goes out immediately, it proves that the charged body is carrying static electricity; if it stays on for a long time, it is definitely leakage.

3. Disconnect the neutral line (N line) of the machine, insert a 220V/15W bulb between the breakpoint and the shell, and turn on the power after the connection is good. If the bulb lights up, it means that the machine has leakage; if the bulb does not light up, it means that the machine is induced. This is because the leakage current can be large enough to make the bulb light up, while the induced current is only tens of milliamperes, which is not enough to make the bulb light up. This method is more accurate.

4. Use a multimeter to measure the insulation resistance between the machine housing and the circuit. When the measured resistance is greater than 1M, it can be considered as induction charging. When the measured resistance is several thousand ohms or less, it can be considered as leakage and measures must be taken. This is a relatively simple and most commonly used method, but this method is not very reliable and must be further confirmed by other methods.

5. Set the digital multimeter to AC20V, then hold one test lead in one hand and another test lead in the other hand close to the machine casing. When the distance is about 4-5cm, observe the multimeter. If the multimeter displays a voltage of several volts (V), it indicates that the charge is caused by leakage; if the multimeter does not display or the displayed value is very small, it indicates that the casing is charged due to induction.

After distinguishing whether it is leakage or induction charging, different measures need to be taken. If it is induction charging, a grounding wire should be connected to the machine shell, so that there will be no "numb hands" phenomenon in future use, and it will also play a certain role in protecting the machine from leakage; if it is caused by leakage, the machine should be inspected and repaired to find the leakage point, and the machine can be put into use again after strengthening insulation or repairing.

The editor would like to remind everyone that if you are electrocuted while using electrical appliances, you should promptly investigate and repair them, use electricity safely and pay attention to electrical appliance protection, reduce the hazards of electrical appliances around you, protect yourself and your family, and avoid unnecessary losses.