Common electric shock method - Solutions - Huaqiang Electronic Network

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Common types of electric shock are single-phase electric shock and two-phase electric shock. Most electric shock accidents are single-phase electric shock.
In the case where the human body and the earth are not insulated from each other, a certain part of the human body touches any one of the three-phase power lines, and the current flows from the charged wire through the human body into the earth to cause electric shock damage.
(1) Single-phase electric shock In the grid where the neutral point is grounded, the single-phase electric shock occurs as shown in (a). At this time, the voltage touched by the human body is the phase voltage, which is 220 V in the low-voltage power and lighting lines. The current forms a path through the phase line, the human body, the earth, and the neutral grounding device. The consequences of electric shock are often severe.

(2) Two-phase electric shock two-phase electric shock, also called phase-to-phase electric shock, which means that when the human body is insulated from the earth, it is exposed to two different phase lines at the same time, or the human body simultaneously touches two different phases of the electrical equipment. At the location, the current flows from one phase to the other through a phase line, forming a closed loop, as shown in Figure 8-2 (b). Two-phase electric shock is more dangerous than single-phase electric shock, because the line voltage is applied to the human body at this time.

(3) Step voltage electric shock When the insulation of the electrical equipment is damaged or the phase of the line is broken, the potential of the falling point is the potential of the wire, and the current will flow into the ground from the falling place (or the insulation damage). The farther away from the location, the lower the potential. According to the actual measurement, the ground potential is approximately equal to zero at a distance of 20 m from the place where the wire falls.
If someone approaches the place where the wire falls, because the potential of the two feet is different, there is a potential difference between the two feet. This potential difference is called the step voltage. The closer to the current entry point, the larger the step voltage; the farther away from the current entry point, the smaller the step voltage; outside 20m, the step voltage is small and can be regarded as zero. When you find the threat of striding voltage, you should put your feet together, or jump off the danger zone with one leg. Otherwise, it will cause electric shock due to long electric shock.
(4) When the contact voltage is grounded, not only will the stride voltage be shocked, but another form of electric shock, that is, the contact voltage, will be generated.
Due to the unreasonable arrangement of the grounding device, when the grounding device hits the shell, the potential distribution is uneven and a potential distribution region is formed. In this area, when the human body comes into contact with the outer casing of the live device, a contact voltage electric shock occurs. The contact voltage is equal to the phase voltage minus the voltage at which the human body stands on the ground. The closer the human body stands away from the grounding point, the smaller the contact voltage, and vice versa. When the standing point is 20m away from the grounding point, the ground voltage approaches zero and the contact voltage is maximum, which is about 220V of the electrical equipment.
Although electric shock accidents always occur suddenly, electric shockers generally do not die immediately. They are often “false deaths”. On-site personnel should take the initiative to promptly disconnect the electric shock from the power supply and immediately use the correct rescue method to rescue them.