● 8~10mA. It is difficult to get rid of the electrode by hand, and there is severe pain (finger joints);
● 20~25mA The hand is paralyzed quickly, cannot get rid of the electrode automatically, and it is difficult to breathe;
● 50~80 mA, breathing difficulties, atrial tremor;
● 90~100 mA. Heart palsy and stop beating.
In the work of electric power workers, they often encounter electric shock accidents more or less. One sentence is a good one: an electrician who has not been electric is not a good electrician. Although it is said, after an electric shock accident, some People were attracted, and some people were bounced away. Why?
Stress response
This is caused by the physiological response of electric shock-electric current can cause muscle spasm and paralysis. After a person gets an electric shock, the site of the electric shock will naturally spasm and curl up.
Take the most frequently electrocuted parts, hands and arms as examples: when our hands are electrocuted, the hands will naturally make a fist; after the arms are electrocuted, the arms will curl inwards. If the electric shock is on the outside of the arm, the arm can be curled up after the electric shock to get out of the power source. We regard this method as being "bounced away". In fact, this kind of "bounced away" is not passive, but our arm avoids it by itself.
However, if it is an electric shock on the palm, finger or inside of the arm, after the electric shock, due to the cramping of the fist and the curling of the arm, the wire will be tightened and the electric shock will not be able to be released. Moreover, the electric current numbs the human body, and the longer the electric shock, the less likely it is to withdraw the hand. Therefore, the so-called "sucking" is not passive, but our hands clenched the power supply after being electrocuted.
General low-voltage circuit or high-voltage circuit contact with electric shock, whether it is electric injury or slight numbness, is generally due to the body's stress response. Experienced electricians will cleverly use the phenomenon of spasm after electric shock. It is common to touch the wire with your fingernail when the electric pen is not around after the switch is powered off to detect whether the circuit is successfully powered off. Rather than just disconnect the switch and start construction directly like us.
Magnetic field
The previous paragraph talked about electric shock when contacting the power supply, but in high-voltage circuits (generally above 10kV), it is also possible to get an electric shock without contacting the power supply.
There are two forms of high-voltage non-contact electric shock: arc electric shock and stride electric shock.
1. Arc electric shock refers to when a person is close to the wire but not touching. Due to the high voltage and strong magnetic field on high-voltage wires, induced electricity is generated in the human body. The electric current in the human body also forms a magnetic field. At this time, the two magnetic fields repel each other and will bounce the person away (in fact, it is more appropriate to call "knock fly"). In this process, an electric arc (electric spark) will be generated between the person and the wire, and a "pop" sound will be made.
Although the person is bounced away at this time, the huge current generated by the high-voltage electricity will still cause serious burns to the person. At this moment, it may be fatal. This is why the word "Do not approach" is written next to the high-voltage wires.
2. Stepping electric shock refers to the high-voltage electric conductor in the electrification, which is directly connected to the earth (for example, the wire is hanging to the ground). Then at this time, the earth is charged. If a person has only one fulcrum on the ground (one foot is on the ground), the current cannot enter the human body through this fulcrum and then come out of the human body, it will not form a loop, and will not get an electric shock. But when both feet of a person are on the ground, the situation is completely different.
When the wire hangs on the ground, the electric potential on the ground gradually weakens outward with the wire as the center. When we have two feet, one is close to the center of the circle, and the other is far from the center of the circle, there will be a potential difference between the two feet, thereby generating a voltage. As a result, the human body uses the two feet as the starting point to form a pathway and generate an electric current.
In this case, the person will be electrocuted so that they cannot escape from the location of the shock. This form of electric shock in which two feet step across to generate voltage is called "stride voltage." In fact, it is not just two feet, as long as the two fulcrums of the human body are on the ground, this form of electric shock may occur.
So if someone in life is unfortunately caught by electricity, how can we rescue him?
Please remember: we must not try to use our hands to directly pull the electric shocker away from the circuit, because in this way you may also be attracted, which is very, very dangerous. The correct way is to use a dry bamboo pole or wooden stick to pick up the wires on the person who is shocked. Be careful not to let the loose wires touch your body. For those who have been unconscious and whose heart has stopped beating, we should use artificial respiration to make them awaken as soon as possible to avoid losing the best rescue opportunity due to too long delay. Call ambulance as soon as possible, cherish life, everyone is responsible!