The first paper on safe use of electricity
In modern life, the use of electricity has been everywhere. Accordingly, how to use electricity safely has become a problem that needs more and more attention in life.
Electric shock accidents often happen suddenly without any warning, which makes people unprepared. But most of them have their own internal reasons.
Product quality defect
Although the state has set strict quality standards for all kinds of household appliances and industrial appliances, especially in terms of safety performance, different safe voltage grades are stipulated according to factors such as the environment in which the appliances are used, whether the human body can touch them, and whether it is necessary to touch the human body when using them. However, in actual production, there are still some defects in the design and manufacturing process of many products, which makes the leakage current of some electrical products too large, leading to leakage accidents, which may cause the danger of electric shock in serious cases.
Improper use of products
Some users of electrical appliances did not install and use the equipment according to the provisions and requirements of the product manual. If the wiring is wrong, the grounded electrical shell is not grounded, and the electrical equipment is still used when it is aging, insulation is damaged, and the environment is harsh (wet, high temperature, dusty, corrosive gas), it may lead to electric shock.
The line or equipment installation is unqualified.
For example, when erecting temporary lines, bamboo poles are used instead of poles, or the lines are erected too low, which makes people easily break when passing by, causing electric shock. Or there is no insulator on the cable where the line is erected, or the porcelain bottle is zeroed, which makes the cable charged and people touch the cable to get an electric shock.
The antenna and telephone line of radio and TV set are set too close to the power cord. If it rains and winds, they will contact the power cord after being disconnected, causing extensive damage.
The insulation part of the lamp holder is damaged, the switch or safety wire is connected to the wrong zero line, or the chandelier wire is too long and the skin is damaged, resulting in electric shock.
The installation position of the socket is too low, which is easy to be touched by curious children, causing electric shock. Using worn wires in indoor wiring, not wrapping the joints with insulating tape, or fixing the wires with nails instead of clamps may cause electric shock accidents.
Violation of operating procedures, do not understand the common sense of safe use of electricity.
There are many such examples, so I won't repeat them here.
In short, although there are many reasons for electric shock, it is mainly due to direct or indirect contact with the human body.
Touching a charged body or approaching a high-voltage charged body may lead to an electric shock accident. Therefore, in order to prevent the occurrence of electric shock accidents, it is necessary to formulate some electricity safety measures according to the causes of electric shock. Here is a brief introduction:
The lighting switch must be connected to the live wire.
If the lighting switch is installed on the zero line, although the light is not on when it is turned off, the phase line of the lamp holder is still on, and people will think that the light is not on and will mistakenly think that it is in a power-off state. In fact, the ground voltage of each point on the lamp is still a dangerous voltage of 220 volts. If people touch these actually charged parts when turning off the lights, it will cause an electric shock accident. Therefore, all kinds of lighting switches or switches of single-phase small-capacity electrical equipment can only be connected in series on the live line to ensure safety.
Correct installation of single-phase three hole socket
Usually, single-phase electrical equipment, especially mobile electrical equipment, should use three-core plug and its supporting three hole socket. There is a special protective zero (grounding) jack in three hole socket. When using zero protection, it is very dangerous for someone to directly connect the wiring pile head of this hole with the zero line that only leads into the socket at the bottom of the socket. Because in case the zero line of the power supply is disconnected, or the fire (phase) line and the zero line of the power supply are connected reversely, its shell and other metal parts will also bring the same voltage as the power supply, resulting in electric shock.
Therefore, when wiring, the special grounding jack should be connected with the special protective grounding wire. When zero protection is adopted, the zero line should be led out from the power supply side, and the zero line introduced into the socket should not be used nearby.
3. Plastic insulated wires cannot be directly buried in the wall.
After long-term use of plastic insulated wires, plastics will age and crack, and the insulation level will be greatly reduced. When the line is overloaded or short-circuited, it is easier to accelerate the insulation damage. Once the wall is damp, it will cause a large area of leakage and endanger personal safety. Plastic insulated wires are directly buried, which is not conducive to line maintenance and repair.
4. Use leakage protector.
Leakage protector, also known as leakage protection switch, is a new type of electrical safety device. Its main purposes are:
(1) Prevent electric shock accidents caused by leakage of electrical equipment and circuits.
(2) To prevent single-phase electric shock accidents in the process of electricity utilization.
(3) Cut off the single-phase grounding fault in the operation of electrical equipment in time to prevent electrical fire accidents caused by leakage.
(4) With the improvement of people's living standards, the number of household appliances is increasing. In the process of using electricity, personal electric shock and fire accidents caused by defects in electrical equipment, improper use and unfavorable safety technical measures have brought undue losses to people's lives and property. The appearance of leakage protector provides a reliable and effective technical means for preventing all kinds of accidents, cutting off power supply in time and protecting equipment and personal safety.
5. Master some common sense of safe electricity use at home.
(1) Every family should have some necessary electrical appliances, such as test pens, screwdrivers and glue tongs. , you must also have all kinds of safety fuses and fuses suitable for the use of household appliances.
(2), every household meter must be equipped with master insurance, and the meter should be equipped with master breaker and leakage protection switch.
(3) In any case, it is forbidden to replace the fuse with copper or iron wire. The size of the fuse must match the capacitance. When replacing the fuse, remove the porcelain box cover and replace it. It is not allowed to overlap the fuse directly in the porcelain box, and it is not allowed to replace the fuse with electricity (without opening the circuit breaker). (4) After the fuse or leakage switch is blown, it is necessary to find out the reason before turning on the power supply. Under any circumstances, it is not allowed to use the short-circuit insurance of wires or the tripping mechanism of forced leakage switch to send electricity.
(5) When purchasing household appliances, carefully check the technical parameters (such as frequency, voltage, etc.). ) meet the local power consumption requirements. It is necessary to know how much electricity is used and whether the existing power supply capacity of the family meets the requirements, especially whether the wiring capacity, plugs, sockets, fuses and meters meet the requirements.
(6) When household power distribution equipment cannot meet the capacity requirements of household appliances, it should be replaced and modified, and it is forbidden to make do with it. Otherwise, overload operation will damage electrical equipment and may also cause electrical fire.
(7) When buying household appliances, you should also know their insulation performance: general insulation, reinforced insulation or double insulation. If grounding is used for leakage protection, grounding wire is essential. Even for electrical equipment with reinforced insulation or double insulation, it is beneficial to do protective grounding or protective grounding.
(8) Household appliances with motors (such as electric fans, etc.). ) you should also know the heat resistance grade and whether they run continuously for a long time. Pay attention to the heat dissipation of household appliances.
(9) Before installing household appliances, you should check the requirements of the product manual for the installation environment, and pay special attention not to install household appliances in an environment with damp heat, dust or flammable, explosive and corrosive gases as much as possible.
(10) When wiring indoors, the phase line and the zero line shall be clearly marked, which shall be consistent with the wiring of household appliances and shall not be wrongly connected.
(1 1) When household appliances are connected to the power supply, an openable switch or plug connector must be used, and it is forbidden to directly insert wires into the socket hole.
(12) For household appliances that require protective grounding or safe zero connection, three-pin plugs and three-pin sockets should be used, and two-pin plugs and two-pin sockets are not allowed to be used instead, resulting in neutral grounding (or zero connection) wires.
(13) It is better to have no connector in the middle of home wiring. If there must be a joint, it should be firmly contacted, wrapped with insulating tape, or a porcelain junction box. Standard uses medical tape instead of electrical tape to wrap joints.
(14) The connection between the wire and the switch, knife, fuse box and lamp holder shall be firm and reliable with good contact. The multi-rubber flexible copper wire connector should be twisted first, and then placed under the connector screw gasket to prevent the thin strands from spreading and contacting another connector and causing short circuit.
(15) Home wiring shall not be directly laid on flammable building materials, and porcelain beads or clamps must be used if wiring is needed on wood; Porcelain sleeves must be used to penetrate the board. Flammable plastics and other flammable materials shall not be used as decorative materials.
(16) Although the grounding or neutral wire is not normally charged, the electrical enclosure will be charged in case of leakage after disconnection; In the case of short circuit, the grounding wire also passes a large current. For the sake of safety, the specification of the grounding (neutral) wire shall not be lower than that of the phase wire, and switches, fuses or connectors shall not be installed on it.
(17) Don't connect the grounding wire to the tap water pipe (because the tap water pipe joint is sealed with insulating tape now and has no grounding function); Do not connect it to the gas pipe (in case of gas explosion caused by electric spark); Don't connect it to the ground wire of the telephone line (in case of strong current and weak current); Nor shall it be connected to the down lead of lightning rod (to prevent lightning strike).
(18) All switches, knives and fuse boxes must be covered. Bakelite cover plate is aging and incomplete and must be replaced. Dirty and wet people must be wiped clean before use after power failure.
(19) Don't drag the power cord on the ground to avoid tripping people and damaging the insulation.
(20) Before the household appliances are put into trial use, all switches and buttons should be placed in the original stop position according to the requirements of the manual, and then the start-stop operation sequence required by the manual should be carried out. If there are moving parts, such as a head-shaking fan, sufficient motion space should be considered in advance.
(2 1) When household appliances are found to be sparking, smoking or burning after being electrified, stop immediately and cut off the power supply for inspection.
(22) When moving household appliances, be sure to cut off the power supply to prevent electric shock.
(23) Around the heating appliance, it is necessary to stay away from flammable materials. Electric stove, heating stove, electric iron and other heating appliances should not be placed directly on the board to avoid fire.
The above is just a brief talk about some common causes of electric shock, measures for safe use of electricity, and common sense of safe use of electricity at home. Definitely not comprehensive enough. In short, in life, if we really want to use electricity safely, we need to study more and pay more attention to ensure the safe use of electricity.
The second paper on safe use of electricity
Abstract: With the continuous development of China's market economy, the use of electrical appliances has been widely popularized. In recent years, more and more electrical equipment has been installed at home, which greatly increases the total power of household electricity. To use electricity safely, we must first have a clear understanding of the signs of safe use of electricity. It is necessary to master the signs of safe use of electricity and become a voluntary propagandist of safe use of electricity. This paper mainly introduces how to identify the signs of safe electricity use.
[Keywords:] safe use of electricity identification signs household appliances
First, the importance of safe use of electricity
In real production and life, due to the inconsistent colors of wires, live wires are mistakenly connected to the casing of electrical equipment, which leads to the electrification of the casing, resulting in electric shock casualties. Incorrect identification of electricity signs can also lead to accidents such as electric shock casualties. Therefore, it is necessary to master the signs of safe use of electricity, become a voluntary propagandist of safe use of electricity, and set an example for safe use of electricity.
Secondly, the commonly used power supply mode in China is three-phase four-wire system, commonly known as three fires and one zero. The main types of electric shock in use are: single-phase electric shock. When the operator or tool touches one of the three-phase power supply lines and the middle line, it will bear the impact of phase voltage (generally 220V) and get an electric shock accident; Two-phase electric shock, when the operator or tool touches the two-phase line in the three-phase power supply, it will bear the impact of line voltage (generally 380V) and an electric shock accident will occur. As far as the forms of electric shock are concerned, direct electric shock and two-phase electric shock are less, while indirect single-phase electric shock is mostly caused by leakage of equipment and tools and people standing on the ground, which also tells us the importance of safe use of electricity. So what can be done to use electricity safely?
Second, the identification mark of safe electricity use
To use electricity safely, we must first have a clear understanding of the signs of safe use of electricity. Safety signs are divided into color signs, graphic signs and lighting signs. Color signs are often used to distinguish wires with different properties and uses or to indicate the safety level of a place, while graphic signs are generally used to warn people not to go to dangerous places nearby or perform dangerous human operations.
(1) color sign
Red: used to indicate prohibition, stop and fire fighting, such as signal lights, signal flags and emergency stop buttons on machines. Are they all transmitted in red? Forbidden? Information.
Yellow: used to mark? Pay attention to safety? 、? Dangerous? Meaning, such as? Watch out for electric shock! ? Wait a minute.
Green: used to mark safety, such as? Can you work here? 、? Grounding? Wait a minute.
Blue: used to mark enforcement, such as? Must wear a helmet? Wait a minute.
Black: Geometry used to mark images, text symbols and warning signs.
In addition to expressing the common sense of electrical operation, color signs are often used to distinguish the characteristics of electrical equipment. For example, the busbar of electrical equipment is yellow in phase A, green in phase B, red in phase C, and the exposed grounding wire is black. In the secondary system, the AC voltage loop is yellow, the AC current loop is green and the signal and warning loop is white.
(2) Graphical signs
? It's a little dangerous, pay attention to safety? Sign. It is often equal except for transformers and electrical equipment. At the same time, it is also a sign of lightning.
Or? Forbidden? Sign. If the number seven is not marked in red, it means that non-professionals should not open the lid, otherwise it is very dangerous.
? Attention? Sign. If it is printed on the back of the TV, is there a postscript? If there is smoke, odor, abnormal sound, etc., please turn off the power immediately. ?
Ground wire? Sign. This means that for safety reasons, electrical equipment should be grounded here.
In addition, different electrical appliances have different requirements in terms of fire prevention, moisture prevention, sun protection, dust prevention and pressure prevention. They will also mark common sense and easy-to-understand signs on the outside of the box or the back of the cabinet.
(3) Light signs
Red light: What does it mean? Dangerous? Or? Does the equipment work normally? For example, the red light of the electric heater indicates work, the red light of the alarm indicates danger, and the red light indicates before the electrical equipment is grounded again? Forbidden area for idle people? .
Yellow light: a sign of danger and normal critical area, such as electric heater? Constant temperature? And warning devices, etc.
Green light: indicates normal work or safe use of electricity. Third, how to use electricity safely
Mastering the signs of safe use of electricity is only the basis of safe use of electricity. If you want to use electricity safely, you should do a good job in the following aspects on the basis of mastering the signs of safe use of electricity (this paper expounds the safe use of electricity at home).
Reasonable layout of (1) switches
The switchboard is equipped with a fuse, which is installed in the fuse. When the current through the fuse exceeds the allowable safety value, it will blow. Therefore, the switchboard cannot be arranged above flammable items to prevent hot melt beads from igniting the items. The fusing current of a fuse is usually the rated current of 1.5? 2.0 times, when the total power of household appliances does not exceed1100W, a fuse of 5 amps is enough. When the current passing through it exceeds 7 amps, it will automatically fuse to achieve the purpose of protection. If the selected insurance conforms to the specifications, but the power supply circuit often blows or the household appliances do not exceed the capacity, the reasons should be found in time to eliminate hidden dangers, and the thick fuse should not be replaced at will or simply replaced with copper wire or iron wire, so that the fuse cannot be protected. The selection of single-phase watt-hour meter should also refer to the total electricity consumption, as long as the total current passing through it does not exceed the rated current of the meter itself. In addition, conditional families can also install leakage protectors, which can act in time to cut off the current when accidents such as electric shock occur in the family.
(2) Correct selection of wires
At present, most of the power lines used by many families were laid ten years ago or earlier, which can't meet the requirements of modern household electrification. First of all, after more than ten years of use, the insulation layer of the wire is gradually loose and aging, causing slight leakage and serious short circuit and fire, so the wire should be replaced. There is also a power load requirement on the wire. When the power load is too large, the aging speed of the insulation layer of the wire will be accelerated, so the selection of the wire should be determined after considering the power current. Finally, it is necessary to correctly select the wire type according to the environment. In a dry room, ordinary insulated wires can be used; in a humid room, insulated wires with protective layers, such as aluminum wires and plastic sheath line, should be used; and flexible wires should be used for electrical equipment that moves frequently.
(3) Reasonable arrangement of lines
A fire broke out in the newly renovated house. After identification, it was migrant workers who laid wires directly in the dado during decoration, and the short circuit of wires ignited the dado. When the wires are exposed, the insulation layer must be prevented from being damaged. When passing through the surface of combustible decorations, you must wear a lightweight flame retardant sleeve. In the room with ceiling, the wires in the ceiling should be wired with metal pipes. For the wires that need to go through the wall, in order to prevent the insulation layer from being damaged, a hard plastic pipe should be built in the wall, and the outlets at both ends extend out of the wall by about 1 cm.
(4) the correct use of household appliances
For TV sets, tape recorders and other household appliances, not only should they be turned off after use, but they should also be unplugged. This is because the power switches of many household appliances are designed on the secondary side of the transformer. If the plug is not broken, the coil and insulation inside the transformer will short-circuit or carbonize and catch fire. In addition, the voltage of China's power grid fluctuates greatly, and the supply voltage of 220 volts can reach 250 volts when the electricity consumption is low. For some electrical appliances with insufficient withstand voltage due to capacitance breakdown, capacitance breakdown will occur. Therefore, voltage stabilizing devices should be added to the line.
(5) Correct use of leakage switch
Only installing leakage switch as line protection device will also have potential safety hazards. Using the toggle switch on the leakage switch to control the power failure for a long time will make the leakage switch fail due to the wear of mechanical parts and lose the leakage protection function; Small leakage switches are generally only equipped with leakage release and overvoltage release, and there is no overcurrent release. When a short circuit fault occurs, the leakage switch or line will be burned because it has no overcurrent protection function. Therefore, the leakage switch must be used with circuit breaker or knife switch.
In a word, the safe use of electricity is something that each of us must care about and take seriously, and we can't be careless at all. At the same time, it also requires us to pay attention to the signs of electricity use in our work and life, so as to use electricity safely.
The third paper on safe use of electricity
Because electricity is not easy to be realized or discovered in time, the knowledge of safe use of electricity cannot be popularized to every construction worker and every manager, especially ordinary workers, temporary workers and migrant workers. This paper analyzes how to make everyone use electricity safely in construction.
Keywords: building safety electricity
With the development of science and technology, most hand tools have been replaced by electric tools to improve labor productivity. From large lifting tools to portable power tools, there are fixed motors and mobile power tools, such as welding and lighting. Electricity is used everywhere. If electricity is used improperly, unexpected accidents will happen immediately. If leakage occurs, it may cause personal electric shock casualties. If electrical appliances are short-circuited, it will cause equipment damage or fire and other vicious accidents. Therefore, it is of far-reaching significance for employees and enterprises to do a good job in the safe use of electricity on the construction site.
As a construction worker, I often come into contact with all kinds of problems related to the safe use of electricity in the construction site and see the hidden dangers in the construction site. Combined with the Ministry of Construction's Technical Specification for Temporary Electricity Use in Construction Site (JGJ46) and other safety management laws and regulations, this paper talks about how to do a good job of safe electricity use in construction site, hoping to provide reference for managers and construction workers who are fighting in the front line of construction, so as to further improve the temporary site.
1 Leaders' attention
The leaders of the construction party should set safety management objectives, establish and improve the responsibility system for safety production at all levels and departments, and clarify the reward and punishment methods; Establish a regular safety inspection system, make clear the safety inspection of key dangerous parts, rectify potential safety hazards in time, and make sure that personnel, time and measures are fixed. Never overcome careless thoughts to ensure the personal safety of employees.
2 power planning
According to the regulations, before the project starts, there must be a special electricity construction organization design, and a site safety technical file should be established, including the layout of on-site electricity facilities, models and specifications of facilities used, load distribution, construction and maintenance records, and related electricity management measures and safety measures. We should plan as a whole and nip in the bud.
3 technical specifications
At the construction site, I often find some irregular or dangerous phenomena, which are roughly as follows:
3. 1 The grounding and neutral point systems do not conform to the specifications.
This phenomenon is common in most construction sites. According to the technical specification for temporary electricity safety on construction site (JGJ46? In 2005), the protective grounding wire of the grounding zero system needs yellow and green wires, but the grounding zero connection on the construction site is chaotic, so I don't say it casually, and some of them are not grounded at all. Even if it is grounded, there is no need for yellow and green wires, which is the lifeline to protect frontline construction workers.
3.2 TN-S (three-phase five-wire system) system is not fully adopted.
Not to mention some old engineering sites, TN-S (three-phase five-wire system) system was not adopted at all. For some newly started sites, although TN-S (three-phase five-wire system) has been adopted as the main system (above the secondary panel), a large part of the load connected below the secondary panel still adopts three-phase four-wire system (such as gantry crane, welding container and other loads). According to the requirements of "Technical Specification for Safety of Temporary Electricity Use in Construction Site" enforced by the state, it is not allowed to use three-phase five-wire system and three-phase four-wire system at the same time in construction site. Some electricity users don't understand this, and think that gantry cranes and electric welding machines don't need tn-s, which is feasible professionally, but it violates the specification requirements enforced by the Ministry of Construction.
3.3 The switch box has no leakage protection device.
This phenomenon is also very common in the construction site, which is not allowed in the current national standard "Installation and Use of Leakage Protector" (GB 13955), which violates? One machine, one brake, one leak and one box? And then what? Three-wire distribution and secondary protection? And other regulations.
3.4 Special lighting circuit has no leakage protection device.
There are some tool rooms in our site, and there are knives in the site office. The fuses of the knives have been replaced by copper wires.
3.5 Distribution box and switch box are illegal? One machine, one brake, one leak and one box? principle
The load switch still uses the old circuit breaker, which has neither leakage protection nor load breaking, which is absolutely not allowed in the standard.
3.6 The safe voltage below 36V is not used for wet operation of on-site lighting.
This point is easily overlooked in the construction site. Some working hours are short or it is inconvenient to connect with safe voltage, and construction workers are lazy to save trouble, but accidents often occur at this time.
3.7 Replace the fuse with other wires.
According to the requirements of the specification, it is forbidden to replace the fuse with a melt that does not meet the original specification.
3.8 The outgoing line under the distribution box is chaotic, and the distribution box is dilapidated and seriously aging.
The ubiquitous old construction site has outstanding security risks. It is common that the distribution box under the new construction site is out of order. It is forbidden to connect the power cord to the distribution box and switch box with bolts. When inspecting and repairing the distribution box and switch box, it is necessary to cut off the corresponding power switch at the first level and hang the power failure sign. Live working is prohibited. In order to save trouble, some construction workers are bold and use electricity to operate. Last year, there was an accident at a construction site, because the knife was installed and the arm was burned by electric arc.
3.9 The switchboard above the second floor is not locked.
According to the regulations, all switchboards above level 2 must be locked. Some distribution boxes and switch boxes are not locked at all, even if they are locked, it is a temporary behavior.
3. The10 wire is aged and skinned, and the wire connector is not wrapped with insulating cloth.
This situation is very common in old project sites, mainly due to insufficient investment and excessive consideration of cost saving. This phenomenon also exists in the new project site, mainly because there are some local phenomena but no inspection and supervision are in place.
3. 1 1 The overall quality of construction personnel is low.
During the construction process, wires and cables were pulled at will, some cables were crushed by engineering vehicles on the ground, and some cables were actually used as ropes.
4 Strengthen management
Combined with the above common hidden dangers of electricity consumption in the construction site, I think we should strengthen the management of safe electricity consumption in the construction site from the following aspects:
4. 1 truly implement the safety responsibility system, especially the safety responsibility of on-site safety management personnel, and really play the role of construction electricity maintenance, patrol and inspection.
4.2 Further strengthen the safe and civilized construction atmosphere at the site, and strengthen the awareness of safe electricity use of personnel at all levels through learning, so that everyone is aware of its harmfulness.
4.3 Strengthen the on-site personnel (including security officers, electricians and electricity users) to learn the professional knowledge of electricity consumption and safety regulations, especially the three-phase five-wire system.
4.4 Give full play to the role of all kinds of safety management personnel and all kinds of professional and technical personnel on site. If the professional knowledge is unclear, ask relevant professionals and invite them to participate in relevant on-site inspections.
4.5 strengthening? Template reference? Take the way of going out and inviting in, learn from the well-done construction site, find out their own shortcomings, and improve the safety awareness of on-site personnel.