Why is the statement 'when checking with a test pen, the light emitted by the pen indicates that the circuit is definitely electrified' incorrect
The light emission of Electroscope (electric pen) can indicate that there is voltage (above 60V) to the ground, but it cannot indicate that there must be current. And commonly referred to as having electricity, it refers to the current passing through the circuit, because the load can only work when there is current.
There will be induced electricity in the circuit, and the neon bubble of the test pen will emit light as long as the voltage exceeds a certain range. Therefore, the light emitted by the test pen may not necessarily be caused by the presence of electricity in the circuit, but may also be induced electricity. And some appliances may have induced electricity, which can also cause the test pen to light up.
Extended Information:
1. Before using the test pen, it is necessary to first verify the function of the test pen to ensure that it is functioning properly. We can test on a known power source to check if the neon bubble is emitting light. We also need to check whether the test pen is damp or flooded to ensure our own safety.
2. Before using a test pen to test the electric field, check whether the voltage in the location is suitable. Do not attempt to test voltage higher than the applicable range with a test pen to avoid danger.
3. When using a test pen, do not touch the metal probe at the front end of the test pen with your hands to avoid electric shock accidents; When using a test pen, be sure to touch the metal plate or hook at the end of the test pen with your hand. If this is not done, although the neon bubble of the test pen does not emit light, it cannot accurately determine whether the charged body is charged because there is no circuit formed between the charged body, test pen, human body, and the earth. Once misjudged, it will be very dangerous.
4. When using a test pen in bright light, special attention should be paid to determining whether the neon bubble of the test pen is truly shining. Many accidents are caused by carelessness and misjudgment, and we must avoid this.
5. It is best to wear insulated shoes when using a test pen to prevent accidents before they occur.
6. When judging whether it is in phase or out of phase, it is important to remember that both feet must be insulated from the ground. Test with both hands, whether both pens are bright or only one is bright, it is the same. Not bright is in phase electricity, as long as it emits light, it is out of phase electricity.
7. When conducting electrical testing on high-voltage equipment using a testing pen, the first step is to strictly follow the operation supervision system. While someone is operating, one person is on the side for supervision. The operator should be in front and the guardian should be at the back. When using a test pen, it is important to pay attention to the compatibility between the rated voltage and the voltage level of the electrical equipment being tested.
8. During electrical testing, operators must wear insulated gloves and insulated shoes to prevent contact voltage from harming the human body. The operator should first conduct an inspection of the test pen on the powered equipment. When conducting live testing on multi-layer lines, the low voltage should be tested first, and then the high voltage should be tested. The upper layer should be tested first and then the lower layer.
