First, the home circuit.
1. The main components of household circuits are low-voltage power supply lines, voltmeters, knives, fuses, electrical appliances, sockets and switches. 2. Connection mode: All electrical appliances in the home circuit are connected in parallel, and each electrical appliance is connected in series with an open circuit.
The on-off of one electrical appliance will not affect the normal work of other electrical appliances, and each socket in the circuit is connected in parallel. The insertion of useful electrical appliances will not affect the normal use of other electrical appliances.
3. Distinguish between live wire, neutral wire and ground wire: The low-voltage power supply line is connected to the household circuit by two wires, and there is no voltage between one wire and the ground, which is called zero wire. There is a voltage of 220V between the other one and the ground, which is called the live wire.
The voltage between live wire and neutral wire is 220 volts. In three hole socket, there is a wire connecting the shell of household appliances with the earth, which is called grounding wire. Although the voltage between the ground wire or live wire and the zero line is 220V, the ground wire and the zero line must not be connected, otherwise it is easy to cause an electric shock accident.
You can use a test pen to distinguish between live wire and zero wire. Touch the metal body at the end of the pen with your hand, and the tip of the pen touches the wire (or the wire connected with the wire). If the neon tube glows, it means it is in contact with the fire line.
4. The watt-hour meter is used to measure how much electricity users use, and it is installed in front of the user's main switch. Electric energy meters can be used to measure the power of electrical appliances.
5. Function of fuse: fuse is used to protect the circuit. Lead-antimony alloy is used for household insurance, with high resistivity and low melting point. When the current is too large, it will generate more heat to make the temperature reach the melting point and automatically fuse and cut off the circuit. Remember not to use other wires instead of fuses.
Selection of fuse: it is normal that the amount of I is greater than I. The fusing current of a general fuse is about twice the rated current.
Second, there are basically two reasons for the excessive current in household circuits. 1. Short circuit: Short circuit means that the current directly connects the neutral line and the live line without going through the electrical appliance. In order to avoid short circuit, it is necessary to check the line in time to see whether the conductor or insulation layer is damaged, whether the wire is bumped or damp.
2. The total power of electrical appliances is too large: when the voltage between live wire and neutral wire is constant, the main current I = p/u ... When the more electrical appliances are connected in parallel, the greater the total power P and the greater the current I, which is the same as the result of short circuit.
The current I is large enough to heat the fuse and automatically cut off the circuit. If there are several high-power appliances connected at home, remember to stagger the use time. Third, the common sense of safe electricity use.
1, cause of electric shock: the human body is a conductor, and the resistance is about 1000 ohm (only varies from person to person). When people get an electric shock, the current will flow into the earth through the human body, and the human body will directly or indirectly touch the fire line, and people will get an electric shock accident. When the current flowing through human body increases to 1 mA, people will feel numb. When the current exceeds 8~ 10 mA, it is difficult for human hands to leave the charged body. When the current passing through the human body reaches 100 mA, people will suffocate and stop their heartbeat in a short time.
Therefore, the main cause of electric shock death in human body is that large current passes through human body. Practice has proved that only the current not higher than 30~40 mA and not higher than 36 volts is safe.
2. Form of electric shock: (1) Single-line electric shock: people standing on the ground touch the fire line or touch objects connected with the fire line. (2) Double-line electric shock: People get an electric shock when their hands touch the live wire and the ground wire respectively.
(3) High-voltage arc electric shock: People get close to high-voltage lines (or high-voltage charged bodies), causing air arc discharge and getting an electric shock (lightning is the same). (4) High-voltage step voltage electric shock: When a person walks into the place where the high-voltage line falls, the step voltage between the front and rear legs exceeds 36 volts and he gets an electric shock.
3. Rules for safe electricity use: Do not touch low-voltage charged bodies (such as 220 volts) and do not approach high-voltage charged bodies. 4. Electric shock first aid: (1) cut off the power supply quickly (turn on the main brake or switch); (2) Turn on the power cord with a dry stick and a bamboo stick, so that the person who gets an electric shock can quickly disconnect the power supply; (3) In case of electrical fire, all parties must cut off the power supply first, and then splash water to put out the fire; (4) Carry out artificial respiration rescue.
2. What is the common sense of safe electricity use in life?
Common sense of safe use of electricity in life
0 1. Every family must have some necessary electrical appliances, such as test pens, screwdrivers, glue pliers, etc. There must also be fuses of various specifications and fuses suitable for household appliances.
02. Every household electric meter must be equipped with master insurance, and the master circuit breaker and leakage protection switch should be installed behind the electric meter.
03. In any case, it is forbidden to use copper or iron wire instead of fuse. 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 tie the fuse directly in the porcelain box, and it is not allowed to replace the fuse with electricity (without opening the circuit breaker).
04. After blowing the fuse or handling the leakage, it is necessary to find out the reason before turning on the power switch. In any case, the fuse cannot be short-circuited, and the tripping mechanism of the leakage switch cannot be forced to send electricity with wires.
05. When purchasing household appliances, you should carefully check whether the technical parameters (such as frequency, voltage, etc.) in the product manual 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.
06. When household power distribution equipment can't meet the capacity requirements of household appliances, it should be replaced and modified, and it is strictly forbidden to make do with it. Otherwise, overload operation will damage electrical equipment and may also cause electrical fire.
07. 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 make protective grounding or zero connection.
08. Household appliances with motors (such as electric fans, etc.). ) also know their heat resistance level and whether they can run continuously for a long time. Pay attention to the heat dissipation of household appliances.
09. 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. During indoor power distribution, the phase line and the zero line should be clearly marked, which should be consistent with the wiring of household appliances and should not be connected by mistake.
3. Small knowledge of household electricity safety
First, the home circuit.
1. The main components of household circuits are low-voltage power supply lines, voltmeters, knives, fuses, electrical appliances, sockets and switches.
2. Connection mode: All electrical appliances in the home circuit are connected in parallel, and each electrical appliance is connected in series with an open circuit. The on-off of one electrical appliance will not affect the normal work of other electrical appliances, and each socket in the circuit is connected in parallel. The insertion of useful electrical appliances will not affect the normal use of other electrical appliances.
3. Distinguish between live wire, neutral wire and ground wire: The low-voltage power supply line is connected to the household circuit by two wires, and there is no voltage between one wire and the ground, which is called zero wire. There is a voltage of 220V between the other one and the ground, which is called the live wire. The voltage between live wire and neutral wire is 220 volts. In three hole socket, there is a wire connecting the shell of household appliances with the earth, which is called grounding wire. Although the voltage between the ground wire or live wire and the zero line is 220V, the ground wire and the zero line must not be connected, otherwise it is easy to cause an electric shock accident. You can use a test pen to distinguish between live wire and zero wire. Touch the metal body at the end of the pen with your hand, and the tip of the pen touches the wire (or the wire connected with the wire). If the neon tube glows, it means it is in contact with the fire line.
4. The watt-hour meter is used to measure how much electricity users use, and it is installed in front of the user's main switch. Electric energy meters can be used to measure the power of electrical appliances. 5. Function of fuse: fuse is used to protect the circuit. Lead-antimony alloy is used for household insurance, with high resistivity and low melting point. When the current is too large, it will generate more heat to make the temperature reach the melting point and automatically fuse and cut off the circuit. Remember not to use other wires instead of fuses. Selection of fuse: it is normal that the amount of I is greater than I. The fusing current of a general fuse is about twice the rated current.
Second, there are basically two reasons for the excessive current in household circuits.
1. Short circuit: Short circuit means that the current directly connects the neutral line and the live line without going through the electrical appliance. In order to avoid short circuit, it is necessary to check the line in time to see whether the conductor or insulation layer is damaged, whether the wire is bumped or damp.
2. The total power of electrical appliances is too large: when the voltage between live wire and neutral wire is constant, the main current I = p/u ... When the more electrical appliances are connected in parallel, the greater the total power P and the greater the current I, which is the same as the result of short circuit. The current I is large enough to heat the fuse and automatically cut off the circuit. If there are several high-power appliances connected at home, remember to stagger the use time.
Third, the common sense of safe electricity use.
1, cause of electric shock: the human body is a conductor, and the resistance is about 1000 ohm (only varies from person to person). When people get an electric shock, the current will flow into the earth through the human body, and the human body will directly or indirectly touch the fire line, and people will get an electric shock accident. When the current flowing through human body increases to 1 mA, people will feel numb. When the current exceeds 8~ 10 mA, it is difficult for human hands to leave the charged body. When the current passing through the human body reaches 100 mA, people will suffocate and stop their heartbeat in a short time. Therefore, the main cause of electric shock death in human body is that large current passes through human body. Practice has proved that only the current not higher than 30~40 mA and not higher than 36 volts is safe.
2, the form of electric shock:
(1) Single-line electric shock: When a person stands on the ground, his hand touches the fire line or an object connected with the fire line.
(2) Double-line electric shock: People get an electric shock when their hands touch the live wire and the ground wire respectively.
(3) High-voltage arc electric shock: People get close to high-voltage lines (or high-voltage charged bodies), causing air arc discharge and getting an electric shock (lightning is the same).
(4) High-voltage step voltage electric shock: When a person walks into the place where the high-voltage line falls, the step voltage between the front and rear legs exceeds 36 volts and he gets an electric shock.
3. Rules for safe electricity use: Do not touch low-voltage charged bodies (such as 220 volts) and do not approach high-voltage charged bodies.
4. Electric shock first aid:
(1) cut off the power supply quickly (turn on the master brake or master switch);
(2) Turn on the power cord with a dry stick and a bamboo stick, so that the person who gets an electric shock can quickly disconnect the power supply;
(3) In case of electrical fire, all parties must cut off the power supply first, and then splash water to put out the fire;
(4) artificial respiration rescue.
4. What is the knowledge about safe use of electricity?
With the continuous improvement of living standards, there are more and more places to use electricity in life. Therefore, it is necessary to master the following basic common sense of safe electricity use: l. Know the main switch of power supply and learn to turn off the main power supply in an emergency. 2. Touch and test the inside of the power socket without hands or conductive objects (such as wires, nails, pins and other metal products). 3. Touch the appliance with wet hands and wipe it with a wet cloth. Don't pull the wire when plugging and unplugging the power plug to prevent the insulation of the wire from being damaged and causing electric shock; The insulation of the wire falls off, so it is necessary to replace the new wire or wrap it with insulating tape in time. 5. When someone gets an electric shock, try to turn off the power in time; Or use dry wooden sticks and other things to separate the electric shock victim from the charged electrical appliances, and don't save people directly by hand; Younger students should appeal to adults for help, and don't handle it by themselves to prevent electric shock. 6. Don't disassemble the power cord, socket and plug at will. Even if it is as simple as installing a light bulb, you should turn off the power first and finish it under the guidance of your parents. Nowadays, more and more household appliances, such as televisions, refrigerators, washing machines, electric irons, hair dryers and electric fans, are used at home. Besides paying attention to the safe use of electricity, we should also pay attention to the following points: 1. Various household appliances have different uses and methods of use, and some of them are more complicated. General household appliances should be studied and used under the guidance of parents, and those with greater risks should not be used by themselves. 2. If there is the smell of smoke, sparks and burning, immediately turn off the power switch and stop using it. At the same time, pay attention to avoid burns when using. 4. Avoid using electrical appliances in humid environment (such as toilet), and don't let electrical appliances get wet, which will not only damage electrical appliances, but also cause electric shock. 5. The fan blades of the electric fan and the dehydration cylinder of the washing machine are rotating at high speed when working, so you can't touch them with your hands or other objects to avoid injury. 6. Stop using TV in thunderstorm weather. Prevent being struck by lightning. 7. If the electric appliance is not used for a long time, it is easy to be damaged by moisture and corrosion, so it needs to be carefully checked before reuse. 8. When purchasing household appliances, you should choose qualified products with reliable quality.
5. Mainly focus on the protection of power facilities, common sense of safe electricity use, and the relationship between electricity use and life.
I found what you said and a composition for you alone. But you need to sum it up yourself. There are many things that are very scattered. (Be sure to choose me and give me points. (Protect power facilities) (Choose a few yourself. Electric energy is the most basic energy in modern society, and people can't live without it almost all the time. It all depends on it. It is the unshirkable responsibility and obligation of every citizen to protect the safety of power facilities. 1. Pay attention to the safe distance between overhead high-voltage lines and ground attachments. Overhead high-voltage lines will form a dangerous area under them because of their drooping weight and cheap wind. Trees in this area should not be too high, miscellaneous trees must be removed, and buildings that may endanger power facilities should not be built. Safety measures must be taken when vehicles with a height of more than 4m pass under high-voltage lines. 2. Pay attention to the safety range of underground cables. There are obvious signs of cable wells and piles on the surface of underground cables in cities. The width of the underground cable protection zone is 0.75m on both sides of the ground pile. It is forbidden to construct and plant trees in this area, and it is not allowed to pile up sundries or dump harmful chemicals. 3. Ensure the safety of high-voltage lines during construction. When working near the high-voltage line, ensure the safe distance between the tower crane and the high-voltage line to avoid the rotating boom touching or damaging the high-voltage line. 4. It is forbidden to connect non-power lines to high-voltage lines. Telephone lines and communication lines should be erected independently. Do not connect electrical equipment directly to power facilities without authorization. 5. Before planning the road, consider whether there are high-voltage poles in the planning area. When it is determined that it is inevitable, work out a feasible plan with the power supply department. 6. Don't fish under high voltage lines. Don't fly kites and throw objects within 300 meters near high-voltage lines. Don't shoot birds at the wires. Prevent the plastic cloth and other sundries in the vegetable greenhouse from scratching the wires. 7 signs for the protection of power facilities, and their signs and pole numbers shall not be covered by advertisements or paints. 8. Don't climb transmission line towers and transformer racks at will, and stay away in rainy days to prevent electric shock or lightning strike. 9. Pay attention to protect the tower foundation and stay cables of overhead power lines. It is forbidden to dig, pile up, drill or dump corrosive chemicals within the planning scope of the outer edge of the foundation. The planning scope of the outer edge of the power tower and cable foundation below 35kV is 5m, and the planning scope of the power tower and cable foundation above 66kV10m is10m. * * * Cooperate with the supervision and severely crack down on illegal acts of cutting and stealing power facilities. Adhere to the idea of "safety first, prevention first", ensure the safety of life and property, truly attach importance to safety from the heart and promote safe production. 2. Be familiar with the location of air switch (commonly known as master brake) in your production site or dormitory (such as toll plaza, construction site, office, dormitory, etc.). ), and cut off the power supply as soon as possible to prevent fire, electric shock or other electrical accidents. Avoid causing greater property losses and personal injuries. 3. Do not connect wires without permission, do not hang clothes and sundries on wires or other electrical equipment, and do not install and use high-power or electrical equipment that does not meet national safety standards without permission. If necessary, apply to the relevant departments for approval, and be installed by electricians. 4. Do not disassemble electrical equipment such as lamps, switches and sockets without permission, and do not use lamps to bake clothes or use them for other purposes. When there are abnormal phenomena such as smoke, arcing and burning smell inside the equipment, the power supply of the equipment should be cut off immediately and the electrician should be notified to carry out maintenance to avoid expanding the fault range and electric shock accidents; When the leakage protector (commonly known as leakage switch) trips, it is not allowed to reclose without permission. 5. When using electrical equipment (such as hair dryer) in the bathroom or in a place with high humidity, ensure good indoor ventilation to avoid electric shock accidents due to poor insulation of electrical equipment. 6. Ensure good heat dissipation of electrical equipment (such as televisions, electric water heaters, computers, stereos, etc.). ), inflammable and explosive articles and sundries are not allowed to be piled up around. 7. Cherish the power resources and form a good habit of using electricity safely and economically. When leaving or not using for a long time, it is necessary to ensure that the power supply (especially electric heating appliances) is cut off before leaving. 8. Electrical appliances and electrical equipment with mechanical transmission must be protected by protective covers, shields or fences, and hands or bodies cannot be put into the mechanical transmission position of running equipment. When cleaning the equipment, it must be carried out under the condition of cutting off the power supply and stopping the machinery to ensure safety, so as to prevent personal injury. 9. Don't climb high-voltage towers, fly kites or engage in other activities near high-voltage lines. 10. Do not enter the electrical room or electrical construction site without the permission of relevant departments. By letting our students watch DVD, we have a deeper understanding of how to use electricity safely and protect power facilities, increase our knowledge of safe use of electricity and awareness of electricity prevention, and play a positive role in reducing and preventing the occurrence of electricity safety accidents. It also makes us realize that every student should learn from an early age, start with me and use electricity safely. In electrical science, everyone strives to be a "safety propagandist". ┃ Example composition ┃ Electricity-this word must be familiar in everyone's dictionary. With the rapid development of the times and the progress of human civilization, the importance of electricity has become increasingly prominent. Nowadays, high technology affects our lives everywhere: it becomes more convenient and colorful. But most of these high-tech products need electricity, so-electricity. With electricity, people can see Xiao Liang in the dark; With electricity, people can enjoy more fun and happiness in life, can't they? When you are comfortably enjoying the electric water heater in the bathroom, when you are happily staring at the TV screen, when you are enjoying entertainment and work at the computer desk, the electric partner silently gives them the power of "life". Electricity is a kind of fast supply and environmental protection energy. Electricity has brought us too many benefits. Imagine if there were no electricity in this developed society. What a troublesome thing this will be. 2008 should be an auspicious year for the Olympic Games. At the beginning of the new year, God played a huge joke on people. When people look at the sky, they don't feel anything unusual.
6. What is the common sense of safe electricity use in family life?
Common sense of safe electricity use should pay attention to the following points:
1. Do not repair or move live lines or equipment in your home by hand, such as desk fans, washing machines, televisions, etc. , to avoid electric shock.
2, don't use metal contact electricity, don't use wet hands to contact the power supply, don't use wet cloth to wipe lamps, switches and other electrical appliances.
3. Install the three hole socket correctly, and don't change the three-hole plug into a two-hole plug at will.
4, the correct use of power cord, not disorderly pull, disorderly wire.
5. Without permission, electrical appliances shall not be installed on the original line.
6. Use household appliances correctly. Do not use unqualified electrical equipment.
7. Develop good habits. Unplug the electric iron, hair dryer, electric stove and other electrical appliances when unattended.
8. Use the power cord correctly. Lead wire and copper wire are prohibited. Replace fuse as fuse, etc.
9. Use leakage protector to prevent personal electric shock and electrical fire.
I hope our answer can help you. If you have any other questions, please call the 24-hour power supply service hotline 95598 for consultation.