Electrician electric shock safety first aid common sense - Solutions - Huaqiang Electronic Network

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First, the way of electric shock
1. Single-phase electric shock This is a common way of electric shock. While a certain part of the human body is in contact with the charged body, the other part is connected to the earth or the neutral line, and a current flows from the charged body through the human body to the earth (or the neutral line) to form a loop.
2. Two-phase electric shock The electric shock caused by the simultaneous contact of different parts of the human body with the two-phase power supply. In this case, regardless of whether the neutral point of the grid is grounded, the line voltage that the human body is subjected to will be higher than that of the single-phase electric shock, and the danger is greater.
3. When the stepping voltage is applied to the ground or the power line (especially the high voltage line) is broken to ground, a strong electric field is formed at and around the grounding point of the wire. When humans and animals enter this area, the potential difference between the two feet is called the step voltage Ust. Under this voltage, current flows from the foot that contacts the high potential, and flows out from the foot that contacts the low potential, thereby forming an electric shock. The magnitude of the stride voltage depends on the distance between the standing point and the grounding point of the human body. The smaller the distance, the larger the stride voltage. When the distance exceeds 20m (theoretically infinity), the stride voltage is considered to be zero and there is no risk of electric shock.
4. Contact voltage electric shock electrical equipment due to insulation damage or other reasons caused by ground fault, such as the two parts of the human body (hand and foot) at the same time contact the equipment shell and the ground, the two parts of the human body will be at different potentials, the potential difference is the contact voltage . An electric shock caused by a contact voltage is called a contact voltage electric shock. In the electrical safety technology, the contact voltage is a person standing at a horizontal distance of 0.8 m from the earthing point of the leakage device. When the leakage device casing touched by the hand is 1.8 m high from the ground, the potential difference UT between the hands and the feet is used as a benchmark. The contact voltage value depends on the distance between the standing point and the grounding point of the human body. The farther the distance is, the larger the contact voltage value is. When the distance exceeds 20m, the contact voltage value is the largest, which is equal to the voltage UTm on the leakage device; When the grounding point is in contact with the leakage device, the contact voltage is zero.
5. The induced voltage is electrically shocked. It refers to an electric shock caused by a person touching a device and a line with an induced voltage. Some uncharged lines generate induced charges due to atmospheric changes (such as lightning activity). Some equipment and lines that may induce voltage after power failure may not be grounded in time. These devices and lines have induced voltages to the ground.
6. The remaining charge is electrically shocked. It refers to an electric shock caused by human discharge when the human body touches the device with residual charge. Equipment with residual charge usually contains energy storage components, such as shunt capacitors, power cables, power transformers, and large-capacity motors. After exiting the operation and performing similar shake-table measurements, it will carry residual charge. Discharge it in time.
Second, the main factors affecting the degree of harm to the human body The severity of the current damage to the human body is related to a variety of factors such as the size, frequency, duration of the human body current, the path through the human body and the size of the human body resistance.
1. The larger the current through the human body, the more obvious the physiological response of the human body. The stronger the induction, the shorter the time required for ventricular fibrillation, and the greater the fatal danger. For power frequency AC, the current is roughly divided into the following three types according to the magnitude of the current through the human body and the different states exhibited by the human body.
(1) Sensory current refers to the minimum current that causes the human body to feel. Experiments have shown that the average sensory current of an adult male is about 1.1 mA, and that of an adult female is 0.7 mA. It is felt that the current will not cause harm to the human body. However, when the current increases, the human body reacts strongly, which may cause indirect accidents such as falling.
(2) Getting rid of current refers to the maximum current that the human body can get rid of the power supply after being shocked. Experiments have shown that the average current of an adult male is about 16 mA, and that of an adult female is about 10 mA.
(3) Fatal current is the minimum current that is life-threatening in a short period of time. Experiments have shown that when the current through the human body reaches 50 mA or more, the heart stops beating and may cause death.
2. The current frequency is generally considered to be the most dangerous for the human body from 40 to 60 Hz. As the frequency increases, the risk will decrease. High-frequency current not only does not harm the human body, but also cures the disease.
3. The longer the energization time of the energization time, the more the current causes the body heat and the electrolyte composition of the human body to increase, resulting in a decrease in the body resistance, which in turn increases the current through the human body, and the risk of electric shock increases.
4. Current path currents can stun through the head; sputum can be caused by the spinal cord; heartbeat is stopped by the heart, blood circulation is interrupted; and suffocation is caused by the respiratory system. Therefore, from left hand to chest is the most dangerous current path, from hand to hand from hand to foot is also a very dangerous current path, from the foot to the foot is a less dangerous current path.
Third, the main point of electric shock emergency electric shock is to move quickly, save the law, must not panic, helpless.
1. First of all, as soon as possible, the electric shock can be removed from the power supply. After the electric shock, the electrician may be gripped due to shackles or unconsciousness, and the power supply cannot be rid of. At this time, getting the electric shocker out of the power supply as soon as possible is the primary factor in saving electric shock.
(1) Low-voltage electric shock accident For low-voltage electric shock accidents, the following methods can be used to remove the electric shock from the power supply.
1) There is a power switch or plug near the electric shock location. You can immediately disconnect the switch or unplug the power supply and cut off the power.
2) The power switch is away from the electric shock. The electrician's pliers with insulated handle or the axe with dry wooden handle can be used to cut off the wires and disconnect the power supply; or the insulation such as dry wood is inserted under the electric shock to block the current.
3) When the electric wire falls on the electric shock or is pressed under the body, use dry clothes, gloves, ropes, wooden boards, wooden sticks and other insulation as tools to open the electric shock or pick up the electric wires to make the electric shocker off the power supply. .
(2) High-voltage electric shock accident For high-voltage electric shock accidents, the following methods can be used to remove the electric shock from the electric shock.
1) Immediately notify the relevant departments of power outages.
2) Put on the insulating gloves, put on the insulated boots, and open the switch with the insulation tool of the corresponding voltage level.
4) Throw the bare metal wire to short-circuit the line to ground, forcing the protection device to operate and disconnect the power supply. Note that one end of the wire should be reliably grounded before throwing the wire and then thrown at the other end.
(3) Precautions for disconnecting the power supply
1) Ambulance personnel should not use hands or other metal and wet objects as ambulance tools, but must use appropriate insulation tools and operate with one hand to prevent electric shock.
2) Prevent the fall of the electric shocker after the electric shock is removed from the power supply.
3) If an electric shock accident occurs at night, the temporary lighting problem should be quickly resolved to facilitate rescue and avoid expanding the accident.
2. On-site first-aid method When the electric shocker is disconnected from the power supply, the symptom should be promptly rescued according to the specific circumstances of the electric shocker. The main ambulance methods for on-site application are artificial respiration and extrathoracic heart compression.
(1) Symptomatic treatment When the electric shock is needed, the treatment is generally handled in the following three situations:
1) If the electric shock is not heavy, the mind is clear, but some are flustered, the limbs are numb, the whole body is weak; or the electric shocker was once in a coma during the electric shock, but has recovered to awake. In this serious situation, the electric shock should be quietly rested, do not walk, observe closely, and ask the doctor to come to the hospital for treatment or to go to the hospital.
2) If the electric shock is more serious, it has lost consciousness, but there is still heartbeat and breathing. At this time, the electric shock should be comfortable and quiet, and keep the air flowing. At the same time, uncover his clothes to facilitate breathing. If the weather is cold, pay attention to heat preservation, and immediately ask a doctor for treatment or hospital.
3) If the person with electric shock is seriously injured, if the breathing stops or the heart stops beating or both have stopped, artificial respiration and chest compression should be performed immediately, and the doctor should be promptly consulted or sent to the hospital. It should be noted that first aid should be carried out as soon as possible, and the doctor cannot be awaited. On the way to the hospital, the first aid cannot be suspended.
(2) The mouth-to-mouth artificial respiration method is a first-aid method applied after the electric shock of the electric shocker stops. Specific steps are as follows:
1) The electric shocker lies on his back and quickly unfastens his collar and belt.
2) The electric shock head is biased to one side, and the foreign matter in the oral cavity is removed to make the breathing smooth. If necessary, the metal spoon can be used to extend from the corner of the mouth to open the mouth.
3) The rescuer stands on the side of the electric shocker, one hand pinches the nose of the electric shocker, one hand rests on the neck of the electric shocker, so that the electric shocker lifts the neck, the head leans back, and then takes a deep breath. Use your mouth to stick to the mouth of the electric shocker, blow it in a big mouth, then relax the nose of the electric shocker and let the gas escape from the lungs of the electric shock. Blow once every 5 s and repeat it until the electric shocker wakes up. When this method is applied to children, it is not necessary to pinch the nose. When the opening is difficult, the lips can be closed tightly, and the nose is blown (ie, mouth-to-nose artificial respiration), and the effect is similar.
(3) The chest external compression method is the first-aid method used after the heartbeat of the electric shocker stops:
1) The electric shocker lies supine on a solid flat or wooden board, and the collar and belt are loosened, and the head is later raised (the neck can be soft), and the rescuer straddles the sides of the waist of the electric shock.
2) The rescuer places the right palm on the sternum of the electric shocker, the middle finger is pointed at the lower end of the neck depression, and the left palm is re-pressed on the back of the right hand (one hand is available for the child).
3) The rescuer squeezes down the body weight, presses 3~4cm, and suddenly releases. Squeeze and relax the movements with rhythm, once every second, squeeze about 60 times per minute, uninterrupted, until the electric shocker wakes up. It is required that the extrusion positioning should be accurate, the force should be appropriate, and the excessive force should be applied to the electric shock to cause internal injury and the excessive force is invalid. Use less force on children.
(4) When the electric shock and heartbeat are stopped, it is allowed to use both "mouth-to-mouth artificial respiration" and "thoracic external compression". For single-person ambulance, blow 2 to 3 times and then squeeze 10 to 15 times to alternate. When ambulanced for two people, blow once every 5s, squeeze once every second, and operate at the same time. Rescue is both quick and patient, and you can't stop first aid even when you are on the way to the hospital. In addition, you can't give a strong shot to the electric shocker, splash cold water or press the wooden board.