Issue of safe voltage 【Daily Question 090224】
Thread Content
What is safe voltage? How was it obtained? What is the **specified safe voltage in volts?**
The safe voltage levels we specify are 12V, 24V, and 36V
Safe voltage: Safe voltage refers to a voltage level that does not cause immediate death or disability in humans. The “safe extra-low voltage” that allows continuous exposure under normal environmental conditions is 36V. 1. Human body’s response to electric current:
Current (mA): 50Hz AC, DC
0.6–1.5: Fingers begin to feel numb; no sensation.
2–3: Intense numbness in the fingers; no sensation.
5–7: Muscle spasms in the fingers; a burning and stinging sensation in the fingers.
8–10: Pain in the finger joints and palms; it becomes difficult to pull the hand away from the power source, but it is still possible to do so. The burning sensation increases.
20–25: Severe pain in the fingers; rapid numbness; unable to pull the hand away from the power source; difficulty breathing; increased burning sensation; muscle spasms in the hands begin.
50–80: Respiratory paralysis; atrial tremors begin; intense burning pain; muscle spasms in the hands; difficulty breathing.
90–100: Respiratory paralysis; this persists for 3 minutes or longer; cardiac paralysis or cessation of atrial beating; respiratory paralysis.
Taking power-frequency current as an example, when a current of around 1 milliampere passes through the human body, it causes uncomfortable sensations such as numbness and tingling ； A current of 10 to 30 milliamps passing through the human body can cause symptoms such as paralysis, severe pain, spasms, elevated blood pressure, and difficulty breathing, but it generally does not pose a life-threatening risk ； A current of over 50 milliamps can cause ventricular fibrillation, which is life-threatening ； A current of over 100 milliamps is sufficient to be fatal. 2. Relationship between the degree of injury and the duration of electric current flow The longer the current flows through the human body, the greater the damage. 3. Relationship between the degree of injury and the path of the current When the current passes through the heart, it can cause nerve disorders, cardiac arrest, and disruption of blood circulation, posing the greatest risk. Among them, the path along which the current flows from the right hand to the left foot is the most dangerous. 4. Relationship between the degree of injury and the type of current The frequency of the current between 40Hz and 60Hz causes the greatest harm to the human body. 5. Relationship between the degree of injury and physical condition Women are more sensitive to the effects of electric current than men ； Children are at greater risk of electric shock than adults ； It is also related to body weight. 6. Relationship between the degree of injury and human body resistance Under a certain voltage, the magnitude of the current flowing through the human body is related to the body’s resistance. Human body resistance varies from person to person and is influenced by factors such as physical constitution, skin moisture level, voltage of the electric shock, age, gender, and even occupation; it is usually between 1000 and 2000 Ω. When the outer layer of keratin is damaged, it drops to 800–1000 Ω. According to Ohm’s law (I = U/R), it can be seen that the magnitude of the current flowing through the human body is related to the applied voltage and the resistance of the human body. In addition to the human body’s own resistance, the resistance of clothing, shoes, pants, etc. that cover the body must also be taken into account. Although the human body’s resistance can generally reach 2 kΩ, there are many factors that affect it. Things such as moist or sweaty skin, the presence of conductive dust, an increased contact area and pressure with charged objects, as well as moisture and dirt on clothing, shoes, and socks, can all reduce the body’s resistance. Therefore, it is usually not possible to calculate in advance the magnitude of the current flowing through the human body. Therefore, to determine safety conditions, safety current is not generally used; instead, safety voltage is employed for estimation. Under normal circumstances, that is, in dry environments where the risk of electric shock is high, the safety voltage is set at 36V. In humid environments where the risk of electric shock is high (such as during welding or maintenance work inside metal containers or pipes), the safety voltage is set at 12V. In this way, the current flowing through the human body in the event of an electric shock can be kept within a limited range, thereby ensuring personal safety to a certain extent. Based on the characteristics of production and working environments, using safety voltages of appropriate levels is a fundamental measure to prevent electric shock injuries and deaths. **The standard \"Safe Voltage\" (GB3805——83) specifies that the rated values for safe voltage in China are 42V, 36V, 24V, 12V, and 6V. The appropriate voltage level should be selected based on factors such as the working environment, the conditions of the operators, the mode of use, the power supply method, and the condition of the electrical circuits. GB3805—93 is the most authoritative basic standard regarding voltages that pose no danger to humans. After a thorough analysis of the data in the table, it can be seen that under the most unfavorable conditions (other than medical applications and situations where the human body is submerged in water), this limit is as follows: the alternating voltage at 15–100 Hz (r.m.s.) shall not exceed 16 V ； The ripple-free DC voltage is 35V. The value of 16V at 50Hz AC is much lower than the 36V commonly used in engineering projects in our country today (and even in junior high school physics textbooks) ； It is even lower than the value of 42V for the safe low voltage specified in GB4706.1—98 (General Safety Requirements for Electrical Appliances for Household and Similar Use), which was issued in 1998. Found on Baidu
Current (mA): 50Hz AC, DC
0.6–1.5: Fingers begin to feel numb; no sensation.
2–3: Intense numbness in the fingers; no sensation.
5–7: Muscle spasms in the fingers; a burning and stinging sensation in the fingers.
8–10: Pain in the finger joints and palms; it becomes difficult to pull the hand away from the power source, but it is still possible to do so. The burning sensation increases.
20–25: Severe pain in the fingers; rapid numbness; unable to pull the hand away from the power source; difficulty breathing; increased burning sensation; muscle spasms in the hands begin.
50–80: Respiratory paralysis; atrial tremors begin; intense burning pain; muscle spasms in the hands; difficulty breathing.
90–100: Respiratory paralysis; this persists for 3 minutes or longer; cardiac paralysis or cessation of atrial beating; respiratory paralysis.
Taking power-frequency current as an example, when a current of around 1 milliampere passes through the human body, it causes uncomfortable sensations such as numbness and tingling ； A current of 10 to 30 milliamps passing through the human body can cause symptoms such as paralysis, severe pain, spasms, elevated blood pressure, and difficulty breathing, but it generally does not pose a life-threatening risk ； A current of over 50 milliamps can cause ventricular fibrillation, which is life-threatening ； A current of over 100 milliamps is sufficient to be fatal. 2. Relationship between the degree of injury and the duration of electric current flow The longer the current flows through the human body, the greater the damage. 3. Relationship between the degree of injury and the path of the current When the current passes through the heart, it can cause nerve disorders, cardiac arrest, and disruption of blood circulation, posing the greatest risk. Among them, the path along which the current flows from the right hand to the left foot is the most dangerous. 4. Relationship between the degree of injury and the type of current The frequency of the current between 40Hz and 60Hz causes the greatest harm to the human body. 5. Relationship between the degree of injury and physical condition Women are more sensitive to the effects of electric current than men ； Children are at greater risk of electric shock than adults ； It is also related to body weight. 6. Relationship between the degree of injury and human body resistance Under a certain voltage, the magnitude of the current flowing through the human body is related to the body’s resistance. Human body resistance varies from person to person and is influenced by factors such as physical constitution, skin moisture level, voltage of the electric shock, age, gender, and even occupation; it is usually between 1000 and 2000 Ω. When the outer layer of keratin is damaged, it drops to 800–1000 Ω. According to Ohm’s law (I = U/R), it can be seen that the magnitude of the current flowing through the human body is related to the applied voltage and the resistance of the human body. In addition to the human body’s own resistance, the resistance of clothing, shoes, pants, etc. that cover the body must also be taken into account. Although the human body’s resistance can generally reach 2 kΩ, there are many factors that affect it. Things such as moist or sweaty skin, the presence of conductive dust, an increased contact area and pressure with charged objects, as well as moisture and dirt on clothing, shoes, and socks, can all reduce the body’s resistance. Therefore, it is usually not possible to calculate in advance the magnitude of the current flowing through the human body. Therefore, to determine safety conditions, safety current is not generally used; instead, safety voltage is employed for estimation. Under normal circumstances, that is, in dry environments where the risk of electric shock is high, the safety voltage is set at 36V. In humid environments where the risk of electric shock is high (such as during welding or maintenance work inside metal containers or pipes), the safety voltage is set at 12V. In this way, the current flowing through the human body in the event of an electric shock can be kept within a limited range, thereby ensuring personal safety to a certain extent. Based on the characteristics of production and working environments, using safety voltages of appropriate levels is a fundamental measure to prevent electric shock injuries and deaths. **The standard \"Safe Voltage\" (GB3805——83) specifies that the rated values for safe voltage in China are 42V, 36V, 24V, 12V, and 6V. The appropriate voltage level should be selected based on factors such as the working environment, the conditions of the operators, the mode of use, the power supply method, and the condition of the electrical circuits. GB3805—93 is the most authoritative basic standard regarding voltages that pose no danger to humans. After a thorough analysis of the data in the table, it can be seen that under the most unfavorable conditions (other than medical applications and situations where the human body is submerged in water), this limit is as follows: the alternating voltage at 15–100 Hz (r.m.s.) shall not exceed 16 V ； The ripple-free DC voltage is 35V. The value of 16V at 50Hz AC is much lower than the 36V commonly used in engineering projects in our country today (and even in junior high school physics textbooks) ； It is even lower than the value of 42V for the safe low voltage specified in GB4706.1—98 (General Safety Requirements for Electrical Appliances for Household and Similar Use), which was issued in 1998. Found on Baidu
Safe voltage: Safe voltage refers to a voltage level that does not cause immediate death or disability in humans. The “safe extra-low voltage” that allows continuous exposure under normal environmental conditions is 36V. 1. Human body’s response to electric current:
Current (mA): 50Hz AC, DC
0.6–1.5: Fingers begin to feel numb; no sensation.
2–3: Intense numbness in the fingers; no sensation.
5–7: Muscle spasms in the fingers; a burning and stinging sensation in the fingers.
8–10: Pain in the finger joints and palms; it becomes difficult to pull the hand away from the power source, but it is still possible to do so. The burning sensation increases.
20–25: Severe pain in the fingers; rapid numbness; unable to pull the hand away from the power source; difficulty breathing; increased burning sensation; muscle spasms in the hands begin.
50–80: Respiratory paralysis; atrial tremors begin; intense burning pain; muscle spasms in the hands; difficulty breathing.
90–100: Respiratory paralysis; this persists for 3 minutes or longer; cardiac paralysis or cessation of atrial beating; respiratory paralysis.
Taking power-frequency current as an example, when a current of around 1 milliampere passes through the human body, it causes uncomfortable sensations such as numbness and tingling ； A current of 10 to 30 milliamps passing through the human body can cause symptoms such as paralysis, severe pain, spasms, elevated blood pressure, and difficulty breathing, but it generally does not pose a life-threatening risk ； A current of over 50 milliamps can cause ventricular fibrillation, which is life-threatening ； A current of over 100 milliamps is sufficient to be fatal. 2. Relationship between the degree of injury and the duration of electric current flow The longer the current flows through the human body, the greater the damage. 3. Relationship between the degree of injury and the path of the current When the current passes through the heart, it can cause nerve disorders, cardiac arrest, and disruption of blood circulation, posing the greatest risk. Among them, the path along which the current flows from the right hand to the left foot is the most dangerous. 4. Relationship between the degree of injury and the type of current The frequency of the current between 40Hz and 60Hz causes the greatest harm to the human body. 5. Relationship between the degree of injury and physical condition Women are more sensitive to the effects of electric current than men ； Children are at greater risk of electric shock than adults ； It is also related to body weight. 6. Relationship between the degree of injury and human body resistance Under a certain voltage, the magnitude of the current flowing through the human body is related to the body’s resistance. Human body resistance varies from person to person and is influenced by factors such as physical constitution, skin moisture level, voltage of the electric shock, age, gender, and even occupation; it is usually between 1000 and 2000 Ω. When the outer layer of keratin is damaged, it drops to 800–1000 Ω. According to Ohm’s law (I = U/R), it can be seen that the magnitude of the current flowing through the human body is related to the applied voltage and the resistance of the human body. In addition to the human body’s own resistance, the resistance of clothing, shoes, pants, etc. that cover the body must also be taken into account. Although the human body’s resistance can generally reach 2 kΩ, there are many factors that affect it. Things such as moist or sweaty skin, the presence of conductive dust, an increased contact area and pressure with charged objects, as well as moisture and dirt on clothing, shoes, and socks, can all reduce the body’s resistance. Therefore, it is usually not possible to calculate in advance the magnitude of the current flowing through the human body. Therefore, to determine safety conditions, safety current is not generally used; instead, safety voltage is employed for estimation. Under normal circumstances, that is, in dry environments where the risk of electric shock is high, the safety voltage is set at 36V. In humid environments where the risk of electric shock is high (such as during welding or maintenance work inside metal containers or pipes), the safety voltage is set at 12V. In this way, the current flowing through the human body in the event of an electric shock can be kept within a limited range, thereby ensuring personal safety to a certain extent. Based on the characteristics of production and working environments, using safety voltages of appropriate levels is a fundamental measure to prevent electric shock injuries and deaths. **The standard \"Safe Voltage\" (GB3805——83) specifies that the rated values for safe voltage in China are 42V, 36V, 24V, 12V, and 6V. The appropriate voltage level should be selected based on factors such as the working environment, the conditions of the operators, the mode of use, the power supply method, and the condition of the electrical circuits. GB3805—93 is the most authoritative basic standard regarding voltages that pose no danger to humans. After a thorough analysis of the data in the table, it can be seen that under the most unfavorable conditions (other than medical applications and situations where the human body is submerged in water), this limit is as follows: the alternating voltage at 15–100 Hz (r.m.s.) shall not exceed 16 V ； The ripple-free DC voltage is 35V. The value of 16V at 50Hz AC is much lower than the 36V commonly used in engineering projects in our country today (and even in junior high school physics textbooks) ； It is even lower than the value of 42V for the safe low voltage specified in GB4706.1—98 (General Safety Requirements for Electrical Appliances for Household and Similar Use), which was issued in 1998.
Current (mA): 50Hz AC, DC
0.6–1.5: Fingers begin to feel numb; no sensation.
2–3: Intense numbness in the fingers; no sensation.
5–7: Muscle spasms in the fingers; a burning and stinging sensation in the fingers.
8–10: Pain in the finger joints and palms; it becomes difficult to pull the hand away from the power source, but it is still possible to do so. The burning sensation increases.
20–25: Severe pain in the fingers; rapid numbness; unable to pull the hand away from the power source; difficulty breathing; increased burning sensation; muscle spasms in the hands begin.
50–80: Respiratory paralysis; atrial tremors begin; intense burning pain; muscle spasms in the hands; difficulty breathing.
90–100: Respiratory paralysis; this persists for 3 minutes or longer; cardiac paralysis or cessation of atrial beating; respiratory paralysis.
Taking power-frequency current as an example, when a current of around 1 milliampere passes through the human body, it causes uncomfortable sensations such as numbness and tingling ； A current of 10 to 30 milliamps passing through the human body can cause symptoms such as paralysis, severe pain, spasms, elevated blood pressure, and difficulty breathing, but it generally does not pose a life-threatening risk ； A current of over 50 milliamps can cause ventricular fibrillation, which is life-threatening ； A current of over 100 milliamps is sufficient to be fatal. 2. Relationship between the degree of injury and the duration of electric current flow The longer the current flows through the human body, the greater the damage. 3. Relationship between the degree of injury and the path of the current When the current passes through the heart, it can cause nerve disorders, cardiac arrest, and disruption of blood circulation, posing the greatest risk. Among them, the path along which the current flows from the right hand to the left foot is the most dangerous. 4. Relationship between the degree of injury and the type of current The frequency of the current between 40Hz and 60Hz causes the greatest harm to the human body. 5. Relationship between the degree of injury and physical condition Women are more sensitive to the effects of electric current than men ； Children are at greater risk of electric shock than adults ； It is also related to body weight. 6. Relationship between the degree of injury and human body resistance Under a certain voltage, the magnitude of the current flowing through the human body is related to the body’s resistance. Human body resistance varies from person to person and is influenced by factors such as physical constitution, skin moisture level, voltage of the electric shock, age, gender, and even occupation; it is usually between 1000 and 2000 Ω. When the outer layer of keratin is damaged, it drops to 800–1000 Ω. According to Ohm’s law (I = U/R), it can be seen that the magnitude of the current flowing through the human body is related to the applied voltage and the resistance of the human body. In addition to the human body’s own resistance, the resistance of clothing, shoes, pants, etc. that cover the body must also be taken into account. Although the human body’s resistance can generally reach 2 kΩ, there are many factors that affect it. Things such as moist or sweaty skin, the presence of conductive dust, an increased contact area and pressure with charged objects, as well as moisture and dirt on clothing, shoes, and socks, can all reduce the body’s resistance. Therefore, it is usually not possible to calculate in advance the magnitude of the current flowing through the human body. Therefore, to determine safety conditions, safety current is not generally used; instead, safety voltage is employed for estimation. Under normal circumstances, that is, in dry environments where the risk of electric shock is high, the safety voltage is set at 36V. In humid environments where the risk of electric shock is high (such as during welding or maintenance work inside metal containers or pipes), the safety voltage is set at 12V. In this way, the current flowing through the human body in the event of an electric shock can be kept within a limited range, thereby ensuring personal safety to a certain extent. Based on the characteristics of production and working environments, using safety voltages of appropriate levels is a fundamental measure to prevent electric shock injuries and deaths. **The standard \"Safe Voltage\" (GB3805——83) specifies that the rated values for safe voltage in China are 42V, 36V, 24V, 12V, and 6V. The appropriate voltage level should be selected based on factors such as the working environment, the conditions of the operators, the mode of use, the power supply method, and the condition of the electrical circuits. GB3805—93 is the most authoritative basic standard regarding voltages that pose no danger to humans. After a thorough analysis of the data in the table, it can be seen that under the most unfavorable conditions (other than medical applications and situations where the human body is submerged in water), this limit is as follows: the alternating voltage at 15–100 Hz (r.m.s.) shall not exceed 16 V ； The ripple-free DC voltage is 35V. The value of 16V at 50Hz AC is much lower than the 36V commonly used in engineering projects in our country today (and even in junior high school physics textbooks) ； It is even lower than the value of 42V for the safe low voltage specified in GB4706.1—98 (General Safety Requirements for Electrical Appliances for Household and Similar Use), which was issued in 1998.
Safe voltage refers to a voltage that will not cause direct death or disability in humans. **The standard \"Safe Voltage\" (GB3805——83) specifies that the rated values for safe voltage in China are 42V, 36V, 24V, 12V, and 6V. The appropriate voltage level should be selected based on factors such as the working environment, the conditions of the operators, the mode of use, the power supply method, and the condition of the electrical circuits.
1. Depending on the characteristics of the production and working environments, using safety voltages of appropriate levels is a fundamental measure to prevent electric shock accidents and injuries. **The standard \"Safe Voltage\" (GB3805——83) specifies that the rated values for safe voltage in China are 42V, 36V, 24V, 12V, and 6V. The appropriate voltage level should be selected based on factors such as the working environment, the conditions of the operators, the mode of use, the power supply method, and the condition of the electrical circuits. 2. Relationship between the degree of injury and human body resistance: Under a certain voltage, the magnitude of the current flowing through the human body is related to the body’s resistance. Human body resistance varies from person to person and is influenced by factors such as physical constitution, skin moisture level, voltage of the electric shock, age, gender, and even occupation; it is usually between 1000 and 2000 Ω. When the outer layer of keratin is damaged, it drops to 800–1000 Ω. According to Ohm’s law (I = U/R), it can be seen that the magnitude of the current flowing through the human body is related to the applied voltage and the resistance of the human body. In addition to the human body’s own resistance, the resistance of clothing, shoes, pants, etc. that cover the body must also be taken into account. Although the human body’s resistance can generally reach 2 kΩ, there are many factors that affect it. Things such as moist or sweaty skin, the presence of conductive dust, an increased contact area and pressure with charged objects, as well as moisture and dirt on clothing, shoes, and socks, can all reduce the body’s resistance. Therefore, it is usually not possible to calculate in advance the magnitude of the current flowing through the human body. Therefore, to determine safety conditions, safety current is not generally used; instead, safety voltage is employed for estimation. Under normal circumstances, that is, in dry environments where the risk of electric shock is high, the safety voltage is set at 36V. In humid environments where the risk of electric shock is high (such as during welding or maintenance work inside metal containers or pipes), the safety voltage is set at 12V. In this way, the current flowing through the human body in the event of an electric shock can be kept within a limited range, thereby ensuring personal safety to a certain extent.
Safe voltage refers to a voltage that will not cause direct death or disability in humans. The safe voltage is no more than 42V.
The so-called safe voltage； It refers to voltages that pose little risk to human safety, as opposed to high and low voltages. The voltage values are generally 36 volts, 24 volts, and 12 volts. Under various different conditions, the resistance of the human body also varies. It is generally around 10,000 to 100,000 euros (though there are lower amounts as well); assuming a value of around 800 euros, experimental analysis shows that the maximum current at power frequency that the human body can tolerate is approximately 50 milliamps, or 0.05 amps. On this basis, and using Ohm’s law, it can be determined that the maximum allowable operating frequency voltage for the human body is approximately 40 volts. Therefore, 36 volts is generally taken as the safe voltage. Nevertheless, for those workplaces with poor working conditions – namely places where electrical conductivity is high, human body resistance is low, or where there is frequent contact with metal containers such as metal pipes, boilers, and cables in underground tunnels – the safe voltage should be set even lower, typically at 12 volts. Therefore, in practice, 12 volts is often referred to as an absolutely safe voltage. Countries have different regulations regarding safe voltage levels; some specify 50 volts or 40 volts, while others specify 36 volts or 24 volts, etc. The International Electrotechnical Commission sets the limit for contact voltage (equivalent to safe voltage) at 50 volts, and stipulates that safety measures against electric shock need not be implemented when the voltage is below 25 volts. The specified safe AC voltages are now 42V, 36V, 12V, and 6V; 24V has been removed, while the upper limit for safe DC voltages is 72V.
Definition of safe voltage: A voltage that limits the voltage that may be applied to a person to a certain range, such that the current flowing through the body at this voltage does not exceed the allowable level; such a voltage is called a safe voltage. The safe voltage value is determined by the allowable current and resistance for the human body. The allowable current for the human body is the current level that will not pose a life-threatening risk during the period after an electric shock occurs. Under normal circumstances, the current that the human body can tolerate can be considered in terms of the let-go current ； In cases equipped with rapid protection devices to prevent electric shock, the allowable current for the human body can be considered to be 30mA ； In situations where severe secondary accidents are likely to occur, a value of 5mA should be considered, one that will not cause a strong reaction. Our country has set an upper limit for the safe operating voltage at power frequency; that is, under any circumstances, the effective value of the voltage between two conductors or between either conductor and ground must not exceed 50V. This limit is determined based on the allowable current of 30mA for the human body and a resistance of 1700Ω for the human body. The International Electrotechnical Commission also specifies that the upper limit for safe DC voltage is 120 V. In our country, the rated values for safe voltages are specified as 42, 36, 24, 12, and 6 V for the RMS value of the power frequency. If there are no special safety structures or measures, a safe voltage of 42V or 36V should be used ； In work environments such as metal containers, tunnels, and mines where space is limited and movement is difficult, as well as in areas with large-area grounding conductors around, a safe voltage of 24V or 12V should be used. When electrical equipment uses a safe voltage of 24V or higher, protective measures against direct contact electric shock must be taken.
Safe voltage: As opposed to high voltage and low voltage, it refers to a voltage that poses little risk to human safety. The voltage values are generally 36 volts, 24 volts, and 12 volts; according to Ohm’s law (I = U/R), it can be seen that the magnitude of the current flowing through the human body is related to the applied voltage and the resistance of the human body. In addition to the human body’s own resistance, the resistance of clothing, shoes, pants, etc. that cover the body must also be taken into account. Although the human body’s resistance can generally reach 2 kΩ, there are many factors that affect it. Things such as moist or sweaty skin, the presence of conductive dust, an increased contact area and pressure with charged objects, as well as moisture and dirt on clothing, shoes, and socks, can all reduce the body’s resistance. Therefore, it is usually not possible to calculate in advance the magnitude of the current flowing through the human body. Therefore, to determine safety conditions, safety current is not generally used; instead, safety voltage is employed for estimation. Under normal circumstances, that is, in dry environments where the risk of electric shock is high, the safety voltage is set at 36V. In humid environments where the risk of electric shock is high (such as during welding or maintenance work inside metal containers or pipes), the safety voltage is set at 12V. In this way, the current flowing through the human body in the event of an electric shock can be kept within a limited range, thereby ensuring personal safety to a certain extent. The specified safe AC voltages are now 42V, 36V, 12V, and 6V; 24V has been removed, while the upper limit for safe DC voltages is 72V.
The voltage that can be applied to the human body is restricted to a certain range, so that the current flowing through the body at such a voltage does not exceed the allowable level; this voltage is known as a safe voltage. In China, the rated values for safe voltages at the power frequency effective value are 42, 36, 24, 12, and 6 V. If there are no special safety structures or measures, a safe voltage of 42V or 36V should be used ； In work environments such as metal containers, tunnels, and mines where space is limited and movement is difficult, as well as in areas with large-area grounding conductors around, a safe voltage of 24V or 12V should be used. When electrical equipment uses a safe voltage of 24V or higher, protective measures against direct contact electric shock must be taken
Under various environmental conditions, the voltage at which human tissues (such as the skin, heart, lungs, respiratory organs, and nervous system) are not damaged upon contact with a charged object carrying a certain voltage is referred to as a safe voltage. Based on different environmental conditions, our country specifies that the safe voltage levels are 6, 12, 24, 36, and 42, which serve as the rated values for safe voltage. The safe voltage value is determined by the allowable current and resistance for the human body. The allowable current for the human body is the current level that will not pose a life-threatening risk during the period after an electric shock occurs. Under normal circumstances, the current that the human body can tolerate can be considered in terms of the let-go current ； In cases equipped with rapid protection devices to prevent electric shock, the allowable current for the human body can be considered to be 30mA ； In situations where severe secondary accidents are likely to occur, a value of 5mA should be considered, one that will not cause a strong reaction. Our country has set an upper limit for the safe operating voltage at power frequency; that is, under any circumstances, the effective value of the voltage between two conductors or between either conductor and ground must not exceed 50V. This limit is determined based on the allowable current of 30mA for the human body and a resistance of 1700Ω for the human body. The International Electrotechnical Commission also specifies that the upper limit for safe DC voltage is 120 V.
In addition to the high-voltage and low-voltage levels specified by the regulations, there is also a safe voltage level. The so-called safe voltage ； It refers to voltages that pose little risk to human safety, as opposed to high and low voltages. The voltage values are generally 36 volts, 24 volts, and 12 volts. Under various different conditions, the resistance of the human body also varies. It is generally around 10,000 to 100,000 euros (though there are lower amounts as well); assuming a value of around 800 euros, experimental analysis shows that the maximum current at power frequency that the human body can tolerate is approximately 50 milliamps, or 0.05 amps. On this basis, and using Ohm’s law, it can be determined that the maximum allowable operating frequency voltage for the human body is approximately 40 volts. Therefore, 36 volts is generally taken as the safe voltage. Nevertheless, for those workplaces with poor working conditions – namely places where electrical conductivity is high, human body resistance is low, or where there is frequent contact with metal containers such as metal pipes, boilers, and cables in underground tunnels – the safe voltage should be set even lower, typically at 12 volts. Therefore, in practice, 12 volts is often referred to as an absolutely safe voltage. Countries have different regulations regarding safe voltage levels; some specify 50 volts or 40 volts, while others specify 36 volts or 24 volts, etc. The International Electrotechnical Commission sets the limit for contact voltage (equivalent to safe voltage) at 50 volts, and stipulates that safety measures against electric shock need not be implemented when the voltage is below 25 volts.
Safe voltage is the voltage level at which, under various environmental conditions, human body tissues (such as skin, heart, lungs, respiratory organs, and nervous system) are not damaged when in contact with live conductors carrying such a voltage. Based on different environmental conditions, our country specifies that the safe voltage levels are 6, 12, 24, 36, and 42, which serve as the rated values for safe voltage.
Safe voltage refers to a voltage that will not cause direct death or disability in humans. Safe voltage is determined based on factors such as the safe current that can flow into the human body and the working conditions under which the body is operating. **The standard ‘Safe Voltage’ (GB3805——83) specifies that the acceptable levels for safe voltage in China are 42V, 36V, 24V, 12V, and 6V.
In addition to the high-voltage and low-voltage levels specified by the regulations, there is also a safe voltage level. The so-called safe voltage ； It refers to voltages that pose little risk to human safety, as opposed to high and low voltages. The voltage values are generally 42 volts, 36 volts, 24 volts, 12 volts, and 6 volts. Under various different conditions, the resistance of the human body also varies. It is generally around 10,000 to 100,000 euros (though there are lower amounts as well); assuming a value of around 800 euros, experimental analysis shows that the maximum current at power frequency that the human body can tolerate is approximately 50 milliamps, or 0.05 amps. On this basis, and using Ohm’s law, it can be determined that the maximum allowable operating frequency voltage for the human body is approximately 40 volts. Therefore, 36 volts is generally taken as the safe voltage. Nevertheless, for those workplaces with poor working conditions – namely places where electrical conductivity is high, human body resistance is low, or where there is frequent contact with metal containers such as metal pipes, boilers, and cables in underground tunnels – the safe voltage should be set even lower, typically at 12 volts. Therefore, in practice, 12 volts is often referred to as an absolutely safe voltage. Countries have different regulations regarding safe voltage levels; some specify 50 volts or 40 volts, while others specify 36 volts or 24 volts, etc. The International Electrotechnical Commission sets the limit for contact voltage (equivalent to safe voltage) at 50 volts, and stipulates that safety measures against electric shock need not be implemented when the voltage is below 25 volts.
The so-called safe voltage； It refers to voltages that pose little risk to human safety, as opposed to high and low voltages. The voltage values are generally 36 volts, 24 volts, and 12 volts. Under various different conditions, the resistance of the human body also varies. It is generally around 10,000 to 100,000 euros (though there are lower amounts as well); assuming a value of around 800 euros, experimental analysis shows that the maximum current at power frequency that the human body can tolerate is approximately 50 milliamps, or 0.05 amps. On this basis, and using Ohm’s law, it can be determined that the maximum allowable operating frequency voltage for the human body is approximately 40 volts. Therefore, 36 volts is generally taken as the safe voltage. Nevertheless, for those workplaces with poor working conditions – namely places where electrical conductivity is high, human body resistance is low, or where there is frequent contact with metal containers such as metal pipes, boilers, and cables in underground tunnels – the safe voltage should be set even lower, typically at 12 volts. Therefore, in practice, 12 volts is often referred to as an absolutely safe voltage. Countries have different regulations regarding safe voltage levels; some specify 50 volts or 40 volts, while others specify 36 volts or 24 volts, etc. The International Electrotechnical Commission sets the limit for contact voltage (equivalent to safe voltage) at 50 volts, and stipulates that safety measures against electric shock need not be implemented when the voltage is below 25 volts.
Safe voltage is the voltage that prevents serious harm to people； In our country, 42, 36, 24, 12, and 6 V are designated as safe voltages; I’m not entirely sure in what specific situations they are applied.
1. What is the safe voltage in volts? How was it obtained? Answer: The so-called safe voltage refers to a voltage that, in contrast to high and low voltages, poses little risk to human safety. It generally refers to voltages of 36 volts, 24 volts, and 12 volts. Under various different conditions, the resistance of the human body also varies. It is generally around 10,000 to 100,000 euros, but there are also lower amounts; typically, it is estimated to be around 800 euros ； Experiments have also shown that the maximum current at power frequency that the human body can tolerate is approximately 50 milliamps, or 0.05 amps. Under these conditions, and using Ohm’s law, it can be determined that the maximum allowable operating frequency voltage for the human body is around 40 volts. Therefore, 36 volts is generally selected and specified as the safe voltage. Nevertheless, in locations with poor working conditions (where the conductivity is high, human body resistance is lower, or there is a greater chance of coming into contact with live electrical parts), such as inside large pipes, shafts, and metal containers like boilers, the human body resistance is even lower; therefore, the safe voltage should be set even lower, typically at 24 volts or 12 volts. For a 12-volt voltage, it is also often referred to as an absolutely safe voltage. Different countries around the world have varying regulations regarding safe voltage levels; some specify 50 volts or 40 volts, while others specify 36 volts or 24 volts, and so on. Rules established by the International Electrotechnical Commission ； The limit value for contact voltage (equivalent to safe voltage) is 50 volts ； When the voltage is 25 volts or less, there is no need to consider taking safety measures to prevent electric shock.
Answer: In relatively dry environments with a high risk of electric shock, if the human body resistance is considered to be between 1000 and 1500 Ω, and the current flowing through the body is taken as 30 mA, which is the maximum current that does not cause ventricular fibrillation, then the corresponding safe voltage is 30–45 volts. The International Electrotechnical Commission specifies that the safe voltage should be below 50V, while in China it is set at 36V. For humid environments with a high risk of electric shock, the International Electrotechnical Commission specifies a limit of 25V, while in China it is set at 12V. For swimming pools or other environments where severe secondary accidents can occur due to electric shock, the International Electrotechnical Commission specifies a limit of 2.5V or less; there is no such specification in China. It is generally believed that a safe voltage for such an environment can be 3V
The so-called safe voltage, as opposed to high voltage and low voltage, refers to a voltage that poses little risk to human safety. The voltage values are generally 36 volts, 24 volts, and 12 volts. Under various different conditions, the resistance of the human body also varies. It is generally around 10,000 to 100,000 euros (though there are lower amounts as well); assuming a value of around 800 euros, experimental analysis shows that the maximum current at power frequency that the human body can tolerate is approximately 50 milliamps, or 0.05 amps. On this basis, and using Ohm’s law, it can be determined that the maximum allowable operating frequency voltage for the human body is approximately 40 volts. Therefore, 36 volts is generally taken as the safe voltage. Nevertheless, for those workplaces with poor working conditions – namely places where electrical conductivity is high, human body resistance is low, or where there is frequent contact with metal containers such as metal pipes, boilers, and cables in underground tunnels – the safe voltage should be set even lower, typically at 12 volts. Therefore, in practice, 12 volts is often referred to as an absolutely safe voltage. Countries have different regulations regarding safe voltage levels; some specify 50 volts or 40 volts, while others specify 36 volts or 24 volts, etc. The International Electrotechnical Commission sets the limit for contact voltage (equivalent to safe voltage) at 50 volts, and stipulates that safety measures against electric shock need not be implemented when the voltage is below 25 volts.