【Daily Question No. 118】November 19, 2017

D. Hazards caused by electrical system failures

1. Electric shock accidents (1) Electric shock occurs when an electric current passes through the human body, stimulating the body’s tissues and causing involuntary spasmodic contractions of the muscles. In severe cases, this can disrupt the normal functioning of the heart, lungs, and nervous system, resulting in life-threatening injuries. Based on the way the human body comes into contact with a live electrical conductor, electric shocks can be classified into the following types: ① Single-phase electric shock. It refers to an electric shock that occurs when a part of the human body comes into contact with the ground or another grounded conductor, while another part of the body touches a live phase conductor. According to domestic and international statistics, single-phase electric shock accidents account for over 70% of all electric shock incidents. Therefore, technical measures to prevent electric shock accidents should focus on single-phase electric shock. ②Two-phase electric shock. It refers to an electric shock that occurs when two parts of the human body come into contact with two live conductors at the same time. The danger of two-phase electric shock is generally relatively high. ③Step voltage electric shock. It refers to an electric shock suffered by a standing or walking human body as a result of the voltage that appears between the feet, namely step voltage. The risk of direct electric shock from step voltage is generally low, as the step voltage itself is not high and the current flowing through the body’s vital tissues is small; however, it can cause secondary injuries. (2) Electric injury. These are the damages caused to the human body by the thermal effects, chemical effects, mechanical effects, etc., of electric current. It presents as localized damage. Electric injuries include electric burns, electrostatic burns, skin metallization, mechanical damage, and electro-optic eye injuries, among others. So I think A is correct. D is incorrect. Please provide the answer

Definition: If a person or livestock is within 8 to 10 meters of the point where high-voltage electricity falls. An electric shock accident may occur, and this type of electric shock is known as step voltage shock. I think that electric shock covers a wide range of situations; basically, all electrical accidents should be classified as electric shock accidents. Based on the definition given above, step voltage should be considered an accident resulting from faults in the electrical system.

Electrical failures are accidents caused by damage to the electrical appliance itself or damage to the insulation of the wires.