With the improvement of social and economic living standards, the application of electricity is more and more common. In addition to natural disasters, electric shock injuries caused by improper use of electricity are also increasing. What is electric injury? However, many people don’t know it very well. This article hundred hundred safety net analyzes: the electric injury definition and the cause!
Introduction to electric injury:
Electric injury is commonly known as electric shock, which usually refers to the tissue damage and dysfunction caused by the human body directly touching the power supply or high-voltage electricity passing through the air or other conductive medium to pass the current through the human body, and the severe person will have cardiac and respiratory arrest. When the voltage is over 1000V, it can also cause burns. Lightning damage (lightning stroke) belongs to the category of high voltage damage.
Cause of electric injury:
There are many causes of electric injury, mainly due to the lack of knowledge of safe use of electricity, the installation and maintenance of electrical appliances and wires are not operated according to regulations, and clothes are hung on the wires. High temperature, high humidity and perspiration reduce the skin surface resistance, which is easy to cause electrical damage. Electric damage can be caused by the wire breaking and falling to human body in an accident, or by a tree sheltering from rain in thunderstorm or being hit by lightning with an iron handle umbrella.
As a conductive body, the human body becomes a part of the circuit when it contacts the current. The degree of human injury is closely related to the voltage, current, DC and AC, frequency, power on time, contact position, current direction and meteorological conditions of the environment, especially the voltage. Voltage 40 V is the risk of tissue damage, 220 V can cause ventricular fibrillation, 1000 V can cause respiratory center paralysis. Electric current can depolarize muscle cell membrane, 10-20ma (MA) can make muscle contract, and 50-60ma can cause ventricular fibrillation. Alternating current can make muscles twitch continuously, and can be “held” by the power supply, so that the electric shock can not break away from the power supply. The harm of low frequency alternating current is greater than that of high frequency, especially when the frequency is 50-60Hz per second, it is easy to induce ventricular fibrillation. Therefore, the harm of alternating current is greater than that of direct current. The resistance of different tissues is different under different conditions.
The resistance of dry skin can reach 50000-1000000 Ω (Ohm), that of wet skin can be reduced to 1000-5000 Ω, and that of damaged skin is only 300-500 Ω. The resistance of each tissue increased from small to large in order of blood vessels and lymphatic vessels; tendons, muscles and nerves; fat and skin; bone, palm, heel, scalp and other dense tissues. The larger the tissue resistance, the smaller the current flow. The current generally moves along the tissue with low resistance in the body. The direction of electric current passes through important organs, with serious prognosis. Respiratory arrest is caused by brain stem; ventricular fibrillation and arrest are caused by heart. The duration of power on is related to the degree of damage. When power on is less than 25 ms, generally no electric injury will be caused. When a catheter is used for ECG recording and pacemaker installation, the current does not pass through the skin with high resistance, but through the wire with low resistance or conductive liquid to the heart, which has the chance to cause microshock.
The current energy can be converted into heat, which makes the local tissue temperature rise and causes burns. The electric resistance of deep soft tissues such as human muscle, fat and tendon is smaller than that of skin and bone, which is very easy to be burned by electric heat. It can also cause damage of small nutrient vessels, thrombosis, tissue ischemia, local edema, aggravation of vascular compression, and severe ischemia and necrosis of distal tissues. High voltage can make the local tissue temperature as high as 2000-4000 ℃. Lightning is a kind of direct current with voltage of 3-200 million V and current of 2000-3000 a. As a result, the temperature of lightning is very high at the moment, and the tissue is quickly burned into “carbonization”.
Life is so precious and so fragile. For some people, life and death are only in a flash. We should pay attention to the prevention of electric shock at ordinary times, especially for the elderly and children at home. We should popularize the knowledge of electric shock prevention and take preventive measures. If you want to know more about children’s home electric shock prevention, please go to this safety net to find relevant information.