What safety precautions should be taken to operate the circuit in a humid environment 20

Under normal circumstances, that is, in a dry and electric shock environment, the safety voltage is specified as 24V, and for the wet and electric shock risk environment (such as metal containers, pipeline welding and maintenance), the safety voltage is specified as 12V, so that the current that passes through the human body during the electric shock can be limited to a small range, which can ensure personal safety to a certain extent.

According to the characteristics of the production and work site, the use of the corresponding level of safety voltage is the fundamental measure to prevent the occurrence of electric shock accidents. The national standard "Safety Voltage" (GB3805-83) stipulates that the rated value of safety voltage in China is 42V, 36V, 24V, 12V and 6V, which should be selected according to factors such as the carrying station of the workplace, the operator's conditions, the mode of use, the power supply mode, and the condition of the line.

For example, hand-held power tools used in particularly hazardous environments should use 42V ultra-low voltage; Hand-held lights and spot lights used in environments where there is a risk of electric shock should be used at 36V or 24V ultra-low voltage; The 12V ultra-low voltage is used for the hand-fired ear lamp used in the metal container and in the particularly humid place and other particularly dangerous environments; Underwater operations and other places should use 6V ultra-low voltage.

1.Electricity users must establish a responsibility system for electricity safety posts, and clarify the persons in charge of electricity safety at all levels.

2.Electricity workers must be certified to work.

3.In a particularly humid environment, electrical equipment, cables, wires, etc., should be selected as closed or moisture-proof type.

4.The metal shell of the electrical equipment, the metal frame and the pipes should be well grounded.

5.Mobile power tools and portable power tools should be equipped with leakage protectors or double insulation equipment. For power tools that have been out of service for a long time, the insulation should be measured before use.

6.The running light voltage should not exceed 12V

7.The humid environment should not be operated with electricity, and general operations should be carried out by wearing insulated boots or standing on the insulated platform.

In general, the safety voltage level is 36V, and 12V should be used as the safety voltage for environments with a high risk of electric shock and particularly humid places.

The safe voltage for electrical equipment in particularly humid places is (36V).

The safe voltage is the voltage that does not directly cause death or disability, and the "safe extra low voltage" that allows continuous contact under normal environmental conditions is 36V.

The industry stipulates that the safety voltage is not higher than 36V, the continuous contact safety voltage is 24V, and the safety current is 10mA. The degree of harm to the human body of electric shock mainly depends on the size of the human body current and the length of time of energizing.

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 Li Song to prevent electric shock, the allowable current of the human cherry hole body can generally be considered as 30mA.

Power tool users should adopt insulation measures to reduce the risk of electric shock when using tools in wet areas. Here are the detailed instructions:

1.Make sure that the power tool itself has good insulation properties

When using power tools, the first thing to do is to make sure that the tool itself has good insulation properties. In particular, plugs and wires should be insulated in accordance with standards to prevent current leakage and electric shock accidents.

2.Wear appropriate protective equipment

When carrying out power tool operations, workers should wear appropriate protective equipment, such as rubber gloves, rubber boots, etc., to cut off the contact between the wet site and the human body to ensure safety.

3.Dry the work site

For the damp conditions of the work site, the dampness of the site can be reduced by drying the ground or laying dry materials.

4.Adjust how and when you work

When using power tools in a wet working environment, direct contact with water or wet objects should be avoided as much as possible. At the same time, the working method and time can be adjusted appropriately to reduce the chance of contact with wet items.

5.Strengthen employee safety training

To better manage wet workplaces, companies can enhance employee safety training and increase employee safety awareness about power tools and wet environments. According to different types of work and operation content, formulate corresponding safety specifications and operation guidelines, and provide timely and effective emergency rescue measures.

6.Regularly check the insulation status of power tools

In addition to ensuring that the power tool itself has good insulation properties, the insulation status of the tool should also be checked regularly. For aging or worn insulating materials, replace or repair them in time to ensure the safety and reliability of the tool.

7.Install a leakage protector

In the use of power tools, leakage protectors can be installed to prevent the danger caused by excessive current. The leakage protector has sensitive detection and power-off functions, which can cut off the power supply in time to avoid the occurrence of electric shock accidents.

8.Warning signs and settings for emergency equipment

In summary, power tool users should adopt insulation measures to reduce the risk of electric shock when using tools in wet areas. At the same time, it is also necessary to strengthen the safety training of employees and formulate relevant safety regulations. Only by taking multiple preventive measures to ensure the safety of workers in the humid environment of demolition can we create a safe, healthy and comfortable working environment.

1.An electric shock protector or anti-leakage switch can be installed, and the power supply can be tripped once the electrical appliances and lines leak.

2.Try to install as few electrical appliances as possible, and it is best not to set up other sockets except for the special socket for exhaust fans. If other electrical outlets must be installed, they should be kept away from water sources and equipped with leakage protectors and waterproof and moisture-proof covers.

3.Waterproof and moisture-proof lighting fixtures should be selected; The installation height of exhaust fans, heating and lighting shall not be less than meters.

Measures to prevent electric shock:

1. Protective grounding Protective grounding is to prevent the human body from suffering the risk of electric shock when the insulation of electrical equipment is damaged, and the good connection between the metal shell or frame of electrical equipment and the grounding body. Protective grounding is suitable for use in low power grids where the neutral point is not grounded. The use of protective grounding can only reduce the risk of electric shock, but it cannot completely guarantee personal safety.

2. Protection zero connection In order to prevent people from being electrocuted due to damage to the insulation of electrical equipment, the metal shell of electrical equipment is connected with the neutral line (neutral point of the transformer) of the power grid, which is called protection zero connection. The protection zero connection is suitable for low-voltage power systems where the neutral point of the three-phase four-wire system is directly grounded.

For the use of protection zero connection system requirements: fuses and circuit breakers can not be installed on the zero line to prevent electric shock accidents caused by phase voltage on the zero line when the zero line circuit is disconnected; In the same low-voltage power grid, it is not allowed to use protective grounding for part of the electrical equipment and zero for the other part of the electrical equipment; When connecting to the three-eye socket, it is not allowed to connect the hole of the power zero wire on the socket with the hole of the grounding wire. The correct connection method is to connect the hole of the neutral line of the power supply to the hole of the ground with the wire to the neutral line respectively; In addition to the neutral point must be well grounded, the neutral line must also be repeatedly grounded.

3. Working grounding A certain point in the power system is directly or through special equipment to make a metal connection with the ground, which is called working grounding. The working grounding can reduce the contact voltage of the human body, quickly cut off the power supply, reduce the insulation level of electrical equipment and transmission lines, and meet the special needs of electrical equipment in operation.

4. Leakage protector Its function is to prevent personal electric shock accidents caused by leakage of electrical equipment and lines, and can also be used to prevent fire accidents caused by equipment leakage and to monitor or cut off one-phase grounding faults, and automatically cut off the power supply when the equipment leaks and the shell presents a dangerous voltage to the ground.