Why do people get electrocuted?
Humans have been using electricity for more than 200 years. In addition to bringing industrial progress and convenience to human life, electricity is occasionally accompanied by some accidents, such as electric shock injury or even death. Whether in Taiwan or other countries, there are not many cases of electric shocks. Why do people get electric shocks? Under what circumstances can the conditions for electric shock be achieved? Let us Longzhong tell you one by one!
Why do people get electrocuted?
Not only does water conduct electricity, but people get electrocuted because the human body can conduct electricity, and the human body is not always in a dry state. In addition, the organs and tissues in the human body are infiltrated in body fluids, and the body fluids also contain a lot of metal ions, which have quite good electrical conductivity.
But whether people will get an electric shock depends entirely on whether there is a potential difference between you and the other party. As long as the potentials of each other are different, there will be a potential difference. Once they contact each other, a current loop will be generated and an electric shock will be generated. Therefore, before talking about "electric shock", we must first talk about achieving "electric shock conditions".
electric shock conditions
1. There must be a potential difference (voltage)
potential difference, voltage，It is a physical quantity that measures the energy difference of a unit charge in an electrostatic field due to different electric potentials. There are many reasons for the potential difference, such as: inside the power supply, when the non-electrostatic force moves the positive charge from the negative plate to the positive plate, work is performed on the charge. The physical process of this work is to generate the power supply electromotive force. is the potential difference.
We often see sparrows standing on wires without getting electrocuted. This is because the two feet of the bird are always standing on the same high-voltage wire, and there is no potential difference (voltage) between the two feet, so current cannot be formed. This is also the reason why sparrows can stay safe even if they stop on high-voltage power lines of tens of thousands of volts.
For another example, there are two people standing on high and low voltage lines. As the example of the sparrow said, since both feet are on the same voltage, no current will be generated, and both of them will be very safe; but if they enthusiastically Shaking hands will cause the two people to be electrocuted at the same time due to the current loop generated by the potential difference.
Therefore, here we can know that There will be electric shock if there is current, but it may not be electric shock if there is voltage.
2.Have a current loop (low resistance)
The second condition for achieving electric shock is low resistance. The following will use the common three-control socket at home to explain how to get electric shock. For a three-hole socket, the short hole is usually the 110 V live wire, the long hole is the 0 V neutral wire, and the round hole is the 0 V ground wire.
【Live wire AND Neutral wire】
The most fundamental cause of electric shock under these conditions is that the human body is placed between the live line 110 V and the neutral line 0 V, and is regarded as a load. When a person touches the live wire with one hand and the neutral wire with the other hand, the current comes in from the live wire, a large amount of current directly passes through the human body, and finally returns to the power supply from the neutral wire, and the person will be electrocuted.
【Live wire AND Fire wire】
Directly touch the live wire and the ground wire, the current will pass through the human body along the live wire and return from the ground wire of the socket. Since the ground wire and the neutral wire are connected at the power supply end in ordinary homes, the current will eventually return to the power supply from the neutral wire, and people will be electrocuted.
【Fire wire AND ground】
” barefoot ” Standing on the ground and touching the live wire, the current will pass through the human body and enter the ground. Since the neutral wire of the power supply end is also grounded, macroscopically, it seems that the ground is a wire, so the current passing through the ground will return from the ground wire of the power supply end. to the neutral wire, forming a current loop.
This tells us to remember to wear shoes and not to step on the ground with bare feet(?) Hey~ Just kidding~ It's okay, please don't do such dangerous experiments XD
After the above integration, we can clearly know that to complete the human body electric shock, we must meet: There is a potential difference (ie voltage)+There is a smooth current loop (low resistance) = Generates electric current to electrocute people.
For example, in our ordinary engineering operations, Longzhong often encounters electrical-related operations such as wiring or electrical panel assembly. The environment where we are located is prone to high voltage, and electric shock is only a momentary thing. At this time, we need to Pretty cautious. Longzhong engineers on site never ignore any risks, and would rather pay more attention to ensure the safety of on-site personnel.
Long Zhong has accumulated considerable experience in the field of INESA
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