Causes and prevention of common electric shock acc

Causes and preventive measures of common electric shock accidents in welding and cutting operations

1. Electric shock

electric shock is the physiological reaction and pathological change of internal organs caused by current passing through the human body. Such as tingling, burning sensation, spasm, paralysis, coma, ventricular fibrillation or arrest, dyspnea or cessation, etc. Most of the deaths caused by current are caused by electric shock

2. Electric injury

electric injury is the injury caused by current to the human body, such as electric burn, electric branding, skin metallization, etc

(1) electric burn

electric burn includes contact burn and arc burn. Contact burns occur in high-voltage electric shock accidents, and are caused at the entrance and exit of the current passing through the human skin. Generally, the entrance is more serious than the exit. Although the contact burn area is small, the depth can reach three degrees. The skin at the burn is yellowish brown, which can affect the subcutaneous tissue, muscles, nerves and blood vessels of thermosetting molding board, and even carbonize the bone. Due to the deep injury to human tissue, the wound is difficult to heal. Some even need several zipper express boxes, and the price is not cheap to scab for years

arc burn occurs when the human body is too close to the high-voltage charged body and generates arc discharge due to misoperation. At this time, the high-temperature arc will burn the skin like a flame, and the burned skin will be red, blistered, scorched and necrotic. Arcs can also cause serious eye damage

(2) electric branding

electric branding occurs when the human body is in good contact with the charged body, and a bump trace similar to the shape of the contacted charged body will be left on the skin surface. Sometimes it does not appear immediately after an electric shock, but after I can be separated for a period of time. Electric branding is generally not inflamed or suppurative, but it often causes local numbness and unconsciousness

(3) skin metallization

due to the extremely high temperature of the arc (the central temperature can reach 6000 ~ 10000 ℃), the metal around it can melt, evaporate and splash to the surface of the skin to metalize the skin. After metallization, the skin surface becomes rough and hard, and the skin color is related to the type of metal, or grayish yellow (lead), or green (copper), or blue-green (brass). After metallization, the skin will fall off by itself after a period of time, and generally there will be no adverse consequences

3. physiological injury of electromagnetic field

physiological injury of electromagnetic field refers to the high frequency, which changes the corresponding performance of starch. Under the action of electromagnetic field, organ tissues and their functions will be damaged, mainly manifested in nervous system dysfunction, such as dizziness, headache, insomnia, forgetfulness, hyperhidrosis, palpitation, anorexia and other symptoms, and some people will also have abnormal symptoms such as alopecia, trembling, amblyopia, sexual dysfunction, menstrual disorders and so on. Secondly, there are obvious cardiovascular symptoms, such as arrhythmia, blood pressure changes, heart pain and so on. If the injury is serious, you may lose consciousness in a short time

the harmful effect of electromagnetic field on human body is functional and has the characteristics of hysteresis. That is, the injury is gradually accumulated, and the symptoms will gradually disappear after disengagement. However, if you work under the action of high-intensity electromagnetic fields for a long time, some symptoms may continue to become chronic diseases and even be passed on to future generations

(II) factors related to the degree of harm of current to human body

the degree of harm of current to human body is related to many factors, such as the intensity of current passing through the human body, the duration of power on, the frequency of current, the part (way) of current passing through the human body, and the physical condition of the person who gets an electric shock

1. current intensity

the greater the current passing through the human body, the stronger the physiological response of the human body, and the greater the damage to the human body. According to the physiological response of human body to current and the damage degree of current to human body, current can be roughly divided into sensing current, getting rid of current and fatal current

2. Duration of current passing through human body

the physiological phenomenon of electrocution is ventricular fibrillation. The longer the duration of current passing through the human body, the more likely it is to cause ventricular fibrillation, and the more serious the consequences of electric shock. On the one hand, the longer the power on time is, the more energy is accumulated, and smaller current passing through the human body can cause ventricular fibrillation; On the other hand, because the heart is most sensitive to current in the time gap between contraction and relaxation (about 0.1s), the longer the power on time is, the greater the possibility of overlapping this time gap is, 23. 5% of ventricular fibrillation The greater the possibility of automatic diagnosis. In addition, with a long power on time, the thermal effect and chemical effect of the current will make the human body sweat and tissue electrolysis, so that the resistance of the human body gradually decreases, and the current flowing through the human body gradually increases, making the electric shock injury more serious