When using electrical equipment, the main danger is the occurrence of electric shock and electric injury. The so-called electric shock means that when the electric current passes through the human body, the whole body can be damaged; it is called electric injury only when the human body is partially injured. The most dangerous thing is electric shock.
The harm of current to human is: burn human body, destroy body tissue, cause electrolysis of blood and other organic substances and stimulate nervous system, etc.
The damage degree of current to human body is related to factors such as the intensity of current through human body, the action time and the condition of human body. Facts have proved that when the current through human body is above 0.05A, it will be dangerous; when it is above 0.1A, it can cause death. The longer the electric shock time is, the more dangerous it will be. If the current is 0.015A when electric shock occurs, it is not easy for people to get rid of the power supply.
Human body has certain resistance, especially skin resistance is relatively high. The resistance on the contact surface of every 1cm2 is about 1000 ~ Between 180000Ω. When the skin is moist, the resistance will reduce significantly. If the resistance is smaller, the current passing under a certain voltage will be larger and the risk will be larger. Generally speaking, when the voltage is below 45 V, the current is safe even through human body.
Therefore, the safety voltage (such as safety light) should be below 45 V.
The main reasons of electric shock accidents are:
1) work on the damaged equipment (such as electric motor, wire, electric switch, etc;
2) contact with charged bare wires or shabby wires;
3) no grounding device or poor grounding device;
4) lack of necessary protective equipment.
For the safe use of electrical equipment, besides strictly implementing the safety technical regulations, the following basic safety knowledge should also be paid attention:
1) if the insulation outside the wire is damaged, it should not be used, and the insulation must be wrapped;
2) frequently check whether the grounding device of each electrical equipment is disconnected;
3) push and pull the electric switch quickly, the face should flash, and wear necessary protective equipment;
4) when checking the temperature of the shell of the motor, it is better to use the back of the hand to contact the shell instead of the palm to avoid being absorbed by electricity and being taken off;
5) People who are not familiar with electrical equipment shall not move or repair the equipment without authorization;
6) when cleaning up the electrical equipment, do not wash with water or wipe with wet cloth;
7) a 10mm thick rubber insulation board should be placed in front of the electric switch.
