(1) Different currents passing through human body will cause different physiological reactions. For power frequency current, according to the magnitude of current passing through human body and different reactions of human body, current can be divided into induced current, free current and fatal current.
(1) The sensing current is the minimum current that causes people to feel. The initial feeling of electric current is slight tingling and tingling. Experience shows that the average adult male is 1. 1mA, and the adult female is about 0.7mA.
(2) Get rid of current refers to the maximum current that the human body can get rid of after getting an electric shock. The average escape current of adult males is 65438±06mA, and that of adult females is about 65438±00.5ma. The escape current of children is less than that of adults. It should be pointed out that the ability to get rid of current decreases with the extension of electric shock time. In other words, once you can't get rid of the power supply after getting an electric shock, the consequences will be more serious.
(3) Lethal current refers to the minimum current that endangers human life in a short time. Death by electric shock is ventricular fibrillation caused by electric current. So the current that causes ventricular fibrillation is fatal. 100mA is a fatal current.
(2) Duration of current The longer the duration of current passing through human body, the greater the risk of electric shock injury. Every contraction and expansion of human heart has a gap of about 0. 1s, which is particularly sensitive to current. The longer the power-on time, it will inevitably coincide with the most sensitive gap of the heart, causing electric shock. The longer the power-on time, the lower the resistance of the human body due to factors such as nervous sweating, which leads to the further increase of the current passing through the human body and can cause electric shock.
(3) Current flows through the human body. Current passing through the heart will cause ventricular fibrillation or make the heart stop beating, leading to the interruption of blood circulation and death. Current passing through the central nervous system or related parts will lead to death. Electric current passing through the spinal cord will paralyze people. Generally speaking, the route from head to toe is the most dangerous, followed by unarmed. Although the route from foot to toe is less harmful, it will cause a serious situation that current flows all over the body after falling.
(4) Current types: Direct current and high-frequency current are harmful to human body, but the degree of harm is generally lighter than that of alternating current of 25~300Hz. The minimum perceived current of DC is about 5.2mA for men and 3.5mA for women. The average escape current is about 76mA for men and 5 1mA for women. Different current frequencies of high-frequency current have different degrees of harm to human body. The commonly used power frequency current is economical and reasonable for designing electrical equipment, but from the safety point of view, this current is the most dangerous to human body. As the frequency deviates from this range, the harm of current to human body is reduced. If the frequency is above 1000Hz, the degree of harm is obviously reduced. However, it should be pointed out that high-voltage electricity and high-frequency electricity are also in danger of fatal electric shock. For example, the induced current of 10000 Hz high-frequency alternating current is about12ma for men; Women are about 8 milliamps. The average removal of current is about 75ma； in men; Female, about 50 years old. When the power-on time is 0.03 seconds, the current that may cause ventricular fibrillation is about 1 100 mA. About 500 milliamps in 3 seconds.
(5) When the human body resistance is constant, the higher the voltage acting on the human body, the greater the current passing through the human body, and the greater the risk of electric shock. When a person is exposed to voltage that is not life-threatening, it is called safe voltage. In China, safe voltage is generally 36V, and the safe voltage of lamps in wet and tank tower equipment containers is 12V.
(6) Human condition Whether human health and mental state are normal or not, the degree of electric shock injury is different. People suffering from heart disease, tuberculosis, mental illness, endocrine organ diseases and drunkenness are more seriously injured by electric shock.
When the voltage of the charged body is constant, the greater the resistance of the human body when getting an electric shock, the smaller the current passing through the human body and the less the danger. On the contrary, the degree of danger increases. Under normal circumstances, the resistance of the human body is10 ~100kΩ, which is not a fixed value. If the cutin of the skin is damaged, the skin is wet or there is conductive dust, the human body resistance will drop below 1kω (the internal resistance of the human body is about 500ω). The larger the contact area of human body with charged body, the closer the contact, the smaller the resistance and the more dangerous it is.
Note: Quoted from the Internet.