What is the safe voltage for a person? What is the safe voltage for the human body

36V Industry Regulations The safety voltage is 36V and the safe current is 10mA for the following reasons:

The degree of harm to the human body of electric shock mainly depends on the size of the current passing through the human body and the length of time it is on. The greater the current intensity, the greater the fatal danger; The longer it lasts, the more likely it is to die. The minimum value of current that can be perceived by a person is called the perceived current, which is 1 mA for AC and 5 mA for DC; The maximum current that a person can get rid of after an electric shock is called getting rid of the current, which is 10mA for AC and 50mA for DC; The current that is life-threatening in a relatively short period of time is called a lethal current, such as a current of 100mA passing through the human body for 1s, which can be enough to make a person fatal, so the lethal current is 50mA.

In the case of protection against electric shock, the current allowed by the human body can generally be considered as 30mA.

The human body's response to electric currents:

8 10mA hands have difficulty getting rid of the electrodes and have a sharp pain (finger joints).

20 25mA hands quickly paralyzed, unable to get rid of electrodes automatically, breathing difficult.

50 80mA is difficult to breathe, and the atria begin to tremble.

90 100mA respiratory paralysis, after three seconds the heart begins to paralyze and stops beating.

According to Ohm's law (i u r), it can be known that the magnitude of the current flowing through the body is related to the applied voltage and the resistance of the body. In addition to the human body's own resistance, the human body resistance should also be attached to the human body other than clothing, shoes, pants and other resistance, although the human body resistance can generally reach 5000, however, there are many factors that affect the human body resistance, such as damp sweating, conductive dust, increasing the contact area and pressure with the charged body, as well as the wet oil stain of clothes, shoes, socks, etc., can reduce the human body resistance, so usually the size of the current flowing through the human body can not be calculated in advance. Therefore, in order to determine the safety conditions, the safety current is often not used, but the safety voltage is used to estimate

Under normal circumstances, that is, in a dry and dangerous environment with a greater risk of electric shock, the safety voltage is specified at 36V, and for wet and electric shock environments (such as metal containers, pipeline welding and maintenance), the safety voltage is specified as 12V, so that the current through the human body during electric shock can be limited to a small range, which can ensure personal safety to a certain extent.

If you are a junior high school student, remember that the correct answer is: "Not higher than 36v". It is necessary to write everything in quotation marks, and missing a word is wrong.

The junior high school physics book of the People's Education Edition says that it is 36v (the most authoritative textbook), so it will be wrong to write a local textbook.

What is Safe Voltage? Star Awareness Project

The human body safety voltage is 36 volts.

Under normal circumstances, the safe voltage that the human body can withstand is 36 volts, and the safe current is 10 milliamperes.

The performance of human electrocution: when the injury of the electrocuted person is lighter, he is often more conscious, and only flustered, numbness of the limbs, general weakness and other manifestations will appear, sometimes after the electric shock, it may cause the patient to have local electrical burns, when the injury is more serious, it may make the electrocuted person lose consciousness, dilated pupils, paleness, and even lead to the cessation of the patient's pulse and breathing.

36V is a safe voltage, which refers to a voltage that does not directly cause death or disability, and is allowed to be continuously exposed under normal environmental conditions. The human body will not electrocute people when exposed to voltages below 36V, regardless of the size of the current.

When the human body is exposed to voltages above 36V, 90-100mA current can kill people. The current is compared with the degree of harm to the human body in the following table:

The magnitude of the safe voltage for the human body is related to the current and time it flows through the body. Generally speaking, the smaller the current that the human body is exposed to and the shorter the current action time, the less harmful it is to the human body. According to international standards, the safety standards for human body contact current are as follows:

When the current exposed to by the human body is less than milliampere, it will not cause danger to people's lives; - When the human body is exposed to an electric current between milliamps and 10 milliamps, it may cause muscle twitching in the arm, but it will not cause permanent damage to the person under normal circumstances; - When the human body is exposed to an electric current greater than 10 mA, it may cause heart palsy and in severe cases, death. Therefore, we can consider that the range of human safety voltage is about 0V to 50V. However, it should be noted that this is only a rough reference value, and the specific situation needs to be evaluated and judged according to the actual situation.