Electrical energy is a superior energy for a wide range of applications that continue to benefit humanity. At the same time, electricity has great potential danger to humans. If you can't fully use electricity, it will cause immeasurable losses to people's lives and property.
Electrical energy is a superior energy for a wide range of applications that continue to benefit humanity. At the same time, electricity has great potential danger to humans. If you can't fully use electricity, it will cause immeasurable losses to people's lives and property. Understand the common sense of safe use of electricity, in order to actively and flexibly control the power, to avoid electric shock accidents, and to ensure the safety of people's lives and property. In particular, teachers who teach electrician activities should understand the knowledge of safe electricity use.
The term "safety electricity" refers to electrical workers, production personnel and other users of electricity, taking necessary measures and means under the established environmental conditions to properly use electricity under the premise of ensuring the safety of personnel and equipment.
1. The effect and influence of current on the human body
Since the human body is a conductor, when the human body contacts the live part to form a circuit of current, a current flows through the human body. Current can cause different degrees of damage to the human body, which comes down to two kinds of injuries: one is electric injury; the other is electric shock. Electric injury refers to the local damage caused by current to the outside of the human body. It is due to the thermal effect of the current, the chemical effect, the mechanical effect and the current itself. The molten and evaporated metal particles invade the human body, and the skin is locally burnt, burned and skin. Metallized damage can also cause death. Electric shock refers to the current passing through the human body, causing damage to internal tissues. This kind of injury can cause systemic fever, tingling, muscle twitching, nerve paralysis, ventricular fibrillation, coma, resulting in respiratory suffocation, and the heart stops beating and dying.
(1) Electric shock form
In order to prevent the occurrence of electric shock accidents, we analyze several common forms of electric shock and the human body's response to electric current, so as to clarify the serious harm of current to the human body. There are four types of electric shock.
Single phase electric shock. A part of the human body is in contact with a charged phase line (hot line), and another part is in contact with the earth (or zero line). The current flows from the phase line through the human body to the ground (or the neutral line) to form a loop, called single-phase electric shock. . In the event of electric shock, there are many cases of single-phase electric shock. For example, when repairing live lines and equipment, electrical equipment casings that are not protected or exposed to leakage and insulated wires may cause single-phase electric shock.
Two phases of electric shock. Two-phase electric shock refers to electric shock when different parts of the human body are in contact with two charged phase lines at the same time. At this time, regardless of whether the power grid center is grounded, the human body is exposed to electricity under the influence of voltage, and the line voltage is high, which is very dangerous.
The step voltage is electric shock. When the electrical equipment is short-circuited to the ground or the power line is grounded, a strong electric field is formed on the ground around the conductor. The potential distribution is that the potential is diffused from the grounding point and gradually decreases. When someone enters this area, there is a gap between the two legs. The potential difference, the current flows in from one foot, and the other foot flows out, causing an electric shock, called striding voltage electric shock.
Electric shock on the suspension circuit. After the mains has a transformer with primary and secondary coils insulated from each other, the voltage zero line from the secondary output is not grounded, and is suspended in relation to the earth. If a person stands on the ground and touches one of the wires, there is generally no feeling of electric shock. . But in a large number of electronic devices, such as receivers, amplifiers, etc., it is a metal backplane or printed circuit board for the public "ground" end, if a part of the operator's body touches the bottom plate (connected to the "ground" point), another part of the contact At the high potential end, it will cause electric shock. So in this case, one-handed operation is generally required.
(2) Human body response to current
The body's response to current is very sensitive. The degree of damage to the human body during an electric shock is related to the following factors. Human body resistance. The body resistance is not constant. In different cases, the resistance values ​​vary greatly, usually between 10 and 100 kilohms. The smaller the body resistance, the greater the current passing through the electric shock, and the more serious the injury. The electrical resistance of various parts of the human body is also different, in which the stratum corneum of the skin has the largest electrical resistance, while the fat, bones and nerves are small, and the muscle resistance is the smallest. If a person suffers from horny damage, his body resistance can be reduced to 0.8 to 1 kilo ohm. In this case, it is most likely to bring life-threatening contact with a charged body. The body resistance is changed. The thinner and moister the skin, the smaller the resistance. The larger the skin contact with the charged body, the tighter the resistance and the smaller the resistance. If the current through the human body is larger, the higher the voltage, the longer the use time and the smaller the resistance. Human body resistance is also affected by physical health and mental state. Such as physical weakness, emotional excitement, drunkenness, etc., easy to sweat, so that the body's resistance dropped sharply, so in these cases it is not appropriate to engage in electrical operations.
Damage to the human body by currents of different intensities. A lot of practice tells us that when the human body passes 1 mA AC frequency or 5 mA DC, there is a feeling of hemp and pain. But 10 mA or so can still get rid of the power. More than 50 mAh is very dangerous. If a current of 100 mA is passed through the body, it will cause respiratory suffocation and the heart will stop beating until it dies.
The current of different voltages harms the human body. The higher the voltage of human contact, the greater the current through the human body, the more serious the damage to the human body. In the actual statistics of electric shock, more than 70% died of electric shock at 220 volts or 380 volts AC. The human body resistance of the electric shock is 1 kilometer, and the current passing through the human body at 220 volts has 220 mA, which can quickly kill people. Through a lot of practice, people found that the voltage below 36 volts has no serious threat to the human body, so the voltage below 36 volts is defined as a safe voltage.
Damage to the human body by currents of different frequencies. Experiments have shown that direct current has a decomposing effect on blood; high-frequency current is not only dangerous, but can also be used for medical treatment. That is, the risk of electric shock decreases with the increase of frequency, and the AC of 40 to 60 Hz is the most dangerous.
The relationship between the action time of the current and the injury of the human body. The longer the current acts on the human body, the smaller the body resistance, and the greater the current through the human body, the more serious the damage to the human body. If the power frequency is 50 mA AC, if the action time is not long, it will not die. If it lasts for 10 seconds, it will cause heart ventricular fibrillation, and the heart will stop beating and die.
The harm of the human body through different ways of passing current. Current through the head stuns; through the spinal cord can cause limb paralysis; if through the heart, respiratory system and central nervous system, can lead to neurological disorders, cardiac arrest, blood circulation interruption. It can be seen that current passing through the heart and respiratory system is the most likely to cause electrocution.
2. Electric shock emergency
In the very short period of time, an electric shock accident will cause serious consequences, so an electric shock accident must be carried out. According to the relevant information, 90% of the people who started the rescue within 1 minute after the electric shock may have the possibility of saving. Only 10% of the patients will be treated after 6 minutes of electric shock. If the treatment is only 12 minutes after the electric shock, the survival rate will be saved. Very few. Therefore, it is very important for the electric shock to be rescued in time. The method of treatment is as follows.
(1) disconnected from the power supply
If there is a distribution box, a knife, etc. nearby, the power should be disconnected immediately. If you have tools with insulated handles (such as wire cutters) around you, you can cut the wires. Or use insulated gloves or dry wooden sticks or bamboo poles to pick up the wires on the electric shock absorber. Be careful not to pull the electric shock directly by hand, or use metal or wet things to pick the wires. Otherwise, instead of getting the electric shocker out of the power supply, the rescuer himself becomes an electric shocker. If the electric shock is an electric shock when working at height, it is necessary to prevent the electric shocker from falling.
(2) On-site treatment
When the electric shocker is disconnected from the power supply, if the consciousness is awake, the breathing is normal, and the skin is not burned, just let him rest in the fresh air, let him lie flat, do not walk, prevent sudden horror, physical exhaustion and death. If the person who is electrocuted is unconscious and has difficulty breathing or stops, he must immediately move him to a place with fresh air nearby, perform artificial respiration in time, and ask medical personnel to come to the rescue. If the heart stops beating, it needs to be immediately rescued by chest compression and will be rescued on the way to the hospital. If the electrode is severe and the heartbeat is completely absent, it is necessary to use the artificial respiration method and the chest compression method to simultaneously or alternately rescue.
Artificial Breathing Method: Make the electric shocker lie flat on the back, tilt the head back, so that the tongue does not block the airflow, pinch the nose and breathe a breath, then release the nose and let it slowly return to breathing, about 12 times per minute. This method works well.
Thoracic extrusion method: The rescuer's hands are stacked, and the position is slightly higher than the heart socket (ie, a little between the two nipples). The palm root is pressed down by 3 to 4 cm, and the pressure is about 60 times per minute. After squeezing, the palm root relaxes quickly, allowing the electric shock to restore the chest itself, so that the blood fills the heart and restores the normal heartbeat.
The child can be squeezed with one hand, but the number can be as fast as 100 times per minute. Note: The rescue of electric shockers sometimes takes a long time, so you must be patient and uninterrupted. It is strictly forbidden to use unscientific methods in first aid, such as using wooden boards to press, shake your body, swearing, splashing with water, blindly It is a wrong method such as a strong heart, because it will only make the electric shocker who is dying or in a state of suspended animation, breathing more difficult, and the body temperature is further reduced, thus accelerating its death.
3. Safety knowledge
(1) Identification of whether the terminal or bare wire is energized In any case, it is not possible to manually identify whether the terminal or bare wire is energized. If you need to know if the line has electricity, you should use a good electroscope or electrical instrument.
(2) How to replace the fuse When replacing the fuse, the power should be cut off first. Do not operate the power. If it is necessary to take live work, take safety measures. For example, stand on the rubber plate or wear insulated shoes and wear insulated gloves. And there must be someone to be on duty during the operation.
(3) Treatment of live joints Disassembled or broken exposed joints that have been exposed to the outside must be wrapped in insulating tape in time and hung to a height that the human body does not touch to prevent human touch.
(4) When using lamps above 36 volts, be careful not to use lamps above 36 volts as safe lights.
(5) When several people are working, it is necessary to know that when there are several people performing electrical work, they should inform all personnel before turning on the power.
(6) Ensure that the personal safety of household electrical equipment such as the chassis of the electric fan, the windshield, the antenna of the TV, the door handle of the refrigerator, the outer casing of the washing machine, etc., are all in contact with the human body at any time, and these household appliances are To use single-phase AC, in order to eliminate unsafe factors, use a three-hole socket and plug with a grounding wire. Or take safety measures for their outer casings, commonly known as grounding and zeroing protection, to protect the human body.
Http://news.chinawj.com.cn Submission:
Guanyu Ceramics Tiles are top quality, rectified, low water absorption, acid-resistant, anti-bacterial, non-slip and wear-resistant.
The Roto-Printing technology makes the same design with various look and feeling. You can always find the tile you like to build your own style!
Luxury Lappato Rustic Porcelain Tile / Matt Finished Glazed Surface Porcelain Tile / Customizable Blown Sand Lappato Rustic Porcelain Tile
Application:
1. Flooring, wall tiles in a bathroom, kitchen and other living space.
2. Hotel lobby flooring, airport, super market, shopping mall, warehouse flooring big project etc.
3.Indoor/Outdoor: Indoor,Commercial Area.
Packing information:
SIZE: 600*600 mm: 4PCS/CTN, 32KG/CTN, 1.44SQM/CTN, 840CTN/20′, 1,209SQM/20′, 27,300KG/20′
SIZE:800*800 mm: 3PCS/CTN, 50KG/CTN, 1.92SQM/CTN, 540CTN/20′, 1,036SQM/20′, 27,270KG/20′
In neutral cartons and put on wooden pallet.
Why Guanyu Ceramics?
Guanyu Ceramics, specializing in making mosaics, polished tiles, rustic tiles and glazed internal wall tiles, makes our brand "Guanyu Ceramics" popular around the world and established worldwide distribution Channels in many countries and areas under the support of many clients.
We will supply you:
- Good Quality:
We got ISO9001:2000, ISO14001:2004, GB/T28001-2001 certificate, compulsory 3C certificate and strictly carries out their standard systems. And our inspection deptment supervise all the goods and it makes the goods are what your expected.
- Reasonable Price:
Our reasonable price will help you to enlarge your market.
- 10 years tiles exporting experience:
Over 10 years of exporting experience on tiles guarantee that all the steps of exporting can goes smoothly and it saves your time and money of getting goods.
- Meet Your Needs:
If your requirement go beyond our tiles, please contact us with your tiles designs. We are always happy to discuss your needs.
Please kindly contact us for further details if you are interested, thank you very much!
Lappato Rustic Tile,Luxury Sand Stone Lappato Tile,Stone Lappato Porcelain Tile
Foshan Guanyu Group , http://www.guanyu-group.com