The danger of an electric current with high voltage appears not only if you touch a wire without insulation. A power line wire that breaks during a storm and thunderstorm is no less dangerous. In a certain radius from a live wire, a strong electric field arises, which is dangerous to humans. The insidiousness of the phenomenon lies in the fact that it cannot be seen or felt beforehand, it does not emit sounds or smell. However, if the cable breaks off, it poses a serious danger of stepping voltage.
Content
What is step voltage
When grounded, the cable radiates electricity. In this case, the current does not disappear anywhere, and a spreading area is created on the soil surface within a certain radius. Step voltage is a phenomenon that occurs between the points of an activity zone near an electrical wire with a large current.The conditions for the occurrence of step voltage are the high-voltage cable touching the ground or other surface. The reasons for the occurrence are as follows:
- breakage of the power line cable or local wire;
- substation accident;
- lightning strikes into a power transmission line support;
- short circuit of high voltage wires.
In the event of a break in the electrical substation, a phased automatic shutdown system is activated. First, the line is de-energized, but after a while, the current is re-supplied to the damaged cable. In some cases, the cause of the short circuit is eliminated automatically: the air insulator can be blocked by branches or birds. Therefore, even a dead cable is a potential step voltage hazard.
Maximum damage radius
The step voltage radius directly depends on the voltage applied to the broken wire. A potential danger to humans is electricity with a voltage of more than 360 volts. At a minimum value, the step voltage zone closer than 3 meters to the source of electricity is especially dangerous. With an increase in the value to 1000 volts, an area up to 5 meters is considered dangerous.
In the event of a power line break or an accident at a substation, the current source significantly exceeds 1000 volts. In this case, the radius of destruction reaches 8 meters. At high currents, the danger zone significantly exceeds this value, but the current at a distance of 12-15 meters from the source does not pose a mortal danger. The value of safe electricity for step voltage is 40 volts. At a distance of 8 to 20 meters from the source, the step voltage rarely exceeds this value.
The greatest striking force is obtained when a person stands with one foot on the wire, and the second - a step (80 cm) away from him. In this case, the distance between the feet plays no less a role than the distance from the source. It is at this distance that a potential difference arises between two points, which causes an electric shock to a person.
The level of danger increases significantly in wet weather. So, wet asphalt or soil is a better conductor than dry earth. It has great resistance. Therefore, during rain or in swampy areas, you should be as careful as possible.
Rules for moving in the step voltage zone
The best way to avoid becoming a victim of step voltage is to avoid the danger of being hit. This requires extreme care, especially in wet weather and with limited visibility. When crossing power lines in windy weather, you need to make sure that there are no broken wires. In addition to cables that have fallen to the ground, sources wrapped around poles or trees are a danger. When detected, you should bypass the wire for 10-15 meters. In the event that the cable fell directly next to a person, it is necessary to remain calm and follow the following algorithm:
- Stand straight on 2 legs, bringing your heels together as much as possible;
- Determine the closest path from a potential voltage source, bypassing obstacles;
- Carefully make a turn in the right direction;
- Move from the source with the smallest possible steps;
- After leaving the danger zone, immediately contact the Ministry of Emergency Situations to eliminate the danger.
The most effective way out of the danger zone is to move with goose steps. This means that the front heel practically touches the toe of the back leg, the leg moves to the length of the foot during the step. Thus, the minimum distance between the feet is maintained, which is not enough to cause dangerous stress.
This method of movement takes a lot of effort, but is the safest. Movement must be made as quickly as possible, but without haste and panic (according to statistics, during any emergency, it is panic that causes 80% of accidents). It is strictly forbidden to run or try to jump out of the danger zone.
When exiting, you can gradually increase the step interval by a few centimeters, but it is recommended to do this when you are 5-7 meters away from the source of danger. Signs of step voltage are tingling in the limbs, with a higher voltage value - spasms, sharp pain. In exceptional cases, paralysis of the legs is possible. Spasm of the limbs is especially dangerous, as it causes involuntary muscle contraction and can lead to a fall (after which it is almost impossible to leave the dangerous area on your own).
Another effective, but forbidden by safety precautions, way to safely exit the zone is jumping on one leg. Contact with the ground with only one limb in this case is completely safe, but if you fall on the second leg or arm, there is a risk of a life-threatening injury.
How to pull a person out of the step voltage zone
If you get into a dangerous radius from the source, it is recommended to get out on your own. However, if a person cannot leave it on his own, he must be pulled out.You need to do this in the same way as when leaving the zone: in small steps. In this case, it is required to wrap the hands with dry clothes, at best - with insulating materials, and then slowly, in small steps, pull the person out.
Insulating clothing, such as rubberized boots and gloves, will help you get out of the step voltage zone. It is this type of clothing that is used by workers servicing power lines and emergency services to eliminate malfunctions and hazards.
After leaving the danger zone
The first step is to assess your condition (or the condition of the rescued person by providing first aid to the victim). Usually after the exit the person feels fine, but in some cases there are health problems. It is necessary to focus and assess your condition, pay attention to the heart and lungs. According to WHO statistics, 20% of people after an independent exit from the zone of stepping electricity have problems with these organs. After that, you must contact the Ministry of Emergency Situations to eliminate the danger, and if you suspect poor health, call an ambulance. It will not be superfluous to undergo a medical examination within a few days.
Similar articles:
