Electric current and its influence on a person. OBZhD

BASICS OF SAFE LIFE
Free library / Directory / Basics of safe life

Electric current and its influence on a person. Basics of safe life

Fundamentals of Safe Life Activities (OBZhD)

Electricity is the orderly movement of electric charges. The current strength in the circuit section is directly proportional to the potential difference (i.e., the voltage at the ends of the section) and inversely proportional to the resistance of the circuit section.

The nature and depth of the impact of electric current on the human body depend on the strength and type of current, the time of its action, the path of passage through the human body, the physical and mental state of the latter.

The threshold (sensible) current is about 1 mA. At a higher current, a person begins to feel unpleasant painful muscle contractions, and at a current of 12-15 mA, he is no longer able to control his muscular system and cannot independently break away from the current source. Such a current is called non-letting. The action of a current of more than 25 mA on muscle tissue leads to paralysis of the respiratory muscles and respiratory arrest. With a further increase in current, fibrillation (convulsive contraction) of the heart may occur. A current of 100 mA is considered lethal.

Alternating current is more dangerous than direct current. It matters what parts of the body a person touches the current-carrying part. The most dangerous are those ways in which the brain or spinal cord (head and arms, head - legs), heart and lungs (arms - legs) are affected.

A characteristic case of getting under voltage is contact with one pole or phase of a current source. The voltage acting on a person in this case is called the touch voltage. Particularly dangerous are the areas located on the temples, back, backs of the hands, shins, back of the head and neck.

The effect of electric current on the body is characterized by the main damaging factors:

1) an electric shock that excites the muscles of the body, leading to convulsions, respiratory and cardiac arrest;

2) electrical burns resulting from the release of heat during the passage of current through the human body. Depending on the parameters of the electrical circuit and the condition of the person, redness of the skin, a burn with the formation of;

3) blisters or charring of tissues; when the metal is melted, metallization of the skin occurs with the penetration of pieces of metal into it.

The effect of current on the body is reduced to:

1) heating;

2) electrolysis;

3) mechanical impact.

The mechanical action leads to rupture of tissues, delamination, percussive action of evaporation of fluid from the tissues of the body.

During thermal action, overheating and functional disorder of organs in the path of current flow occur.

The electrolytic effect of the current is expressed in the electrolysis of fluid in the tissues of the body, a change in the composition of the blood.

If there are tissue changes at the site of exposure to electric current, a dry aseptic bandage is applied to the affected part of the body.

To avoid electric shock, it is necessary to carry out all work with electrical equipment and devices after disconnecting them from the electrical circuit.

ESD protection

Constant electrostatic field (ESF) is a field of fixed charges that interacts between them.

The occurrence of static electricity charges occurs during deformation, crushing (spraying) of substances, relative movement of two bodies in contact, layers of liquid and bulk materials, with intensive mixing, crystallization, and also due to induction.

When dielectrics are rubbed, excess charges appear on their surface, electric charges accumulate on dry hands, creating a potential of up to 500 V. The potential difference between a thundercloud and the Earth reaches huge values, measured in hundreds of millions of volts, and a strong electric field arises in the air.

Under favorable conditions, breakdown occurs. Charges tend to accumulate to a greater extent on points or bodies similar in shape to points.

High electric fields are created near these points. For this reason, lightning strikes high free-standing objects (towers, trees, etc.), and therefore it is dangerous for a person to be in open space during a thunderstorm or near individual trees, metal objects.

Along with natural static electric fields in the technosphere and in everyday life, a person is exposed to artificial static electric fields.

Artificial static electric fields are due to the increasing use for the manufacture of household items:

1) toys;

2) shoes;

3) clothes;

4) for interior decoration of residential and public buildings;

5) for the manufacture of building parts of production equipment;

6) equipment;

7) tools;

8) machine parts of various synthetic polymeric materials;

9) dielectrics.

Permissible levels of electrostatic fields are set in GOST 12.1.045-84.

The use of protective equipment for workers is mandatory in cases where the actual levels of electrostatic fields in the workplace exceed 60 kV / m².

When choosing means of protection against static electricity, the features of technological processes, the physical and chemical properties of the processed material, the microclimate of the premises, and others should be taken into account, which determines a differentiated approach in the development of protective measures.

Common means of protection against static electricity are to reduce the generation of electrostatic charges or their removal from the electrified material, what is being achieved:

1) grounding of metal and electrically conductive elements of equipment;

2) an increase in the surface and volume conductivity of dielectrics;

3) installation of neutralizers of static electricity.

Grounding is carried out regardless of the use of other protection methods.

Authors: Alekseev V.S., Zhidkova O.I., Tkachenko N.V.

We recommend interesting articles Section Basics of safe life:

▪ Protection against toxic emissions

▪ Street injury. Warning Rules

▪ Elimination of consequences of emergency situations

See other articles Section Basics of safe life.

Read and write useful comments on this article.

<< Back

Latest news of science and technology, new electronics:

Artificial leather for touch emulation 15.04.2024

In a modern technology world where distance is becoming increasingly commonplace, maintaining connection and a sense of closeness is important. Recent developments in artificial skin by German scientists from Saarland University represent a new era in virtual interactions. German researchers from Saarland University have developed ultra-thin films that can transmit the sensation of touch over a distance. This cutting-edge technology provides new opportunities for virtual communication, especially for those who find themselves far from their loved ones. The ultra-thin films developed by the researchers, just 50 micrometers thick, can be integrated into textiles and worn like a second skin. These films act as sensors that recognize tactile signals from mom or dad, and as actuators that transmit these movements to the baby. Parents' touch to the fabric activates sensors that react to pressure and deform the ultra-thin film. This ... >>

Petgugu Global cat litter 15.04.2024

Taking care of pets can often be a challenge, especially when it comes to keeping your home clean. A new interesting solution from the Petgugu Global startup has been presented, which will make life easier for cat owners and help them keep their home perfectly clean and tidy. Startup Petgugu Global has unveiled a unique cat toilet that can automatically flush feces, keeping your home clean and fresh. This innovative device is equipped with various smart sensors that monitor your pet's toilet activity and activate to automatically clean after use. The device connects to the sewer system and ensures efficient waste removal without the need for intervention from the owner. Additionally, the toilet has a large flushable storage capacity, making it ideal for multi-cat households. The Petgugu cat litter bowl is designed for use with water-soluble litters and offers a range of additional ... >>

The attractiveness of caring men 14.04.2024

The stereotype that women prefer "bad boys" has long been widespread. However, recent research conducted by British scientists from Monash University offers a new perspective on this issue. They looked at how women responded to men's emotional responsibility and willingness to help others. The study's findings could change our understanding of what makes men attractive to women. A study conducted by scientists from Monash University leads to new findings about men's attractiveness to women. In the experiment, women were shown photographs of men with brief stories about their behavior in various situations, including their reaction to an encounter with a homeless person. Some of the men ignored the homeless man, while others helped him, such as buying him food. A study found that men who showed empathy and kindness were more attractive to women compared to men who showed empathy and kindness. ... >>

Random news from the Archive

Plasma gun - a new NATO weapon 30.07.2012

Scientists from the Picatinny Arsenal continue to work on an unusual type of weapon using a laser-induced plasma channel (LIPC). The bottom line is to use a laser beam, which "tears" electrons from air molecules and creates a plasma conductive cord that destroys equipment and manpower.

LIPC lead scientist George Fisher shared the barest details of this secret project: "We can create a very short laser pulse with tremendous energy. In 2-3 trillionths of a second, you can fit energy that exceeds the needs of an entire city."

This nanosecond electrical pulse (nsEP) can be a very powerful weapon. The Pentagon wants to use it to send up to 50 billion watts of optical / electrical power to the target. This is much more than any existing combat laser with a power of about 100-1000 kW. The most powerful nsEP will be able to instantly kill any living creature. Its effect on armored vehicles and fortifications has yet to be studied - it all depends on the power and duration of the pulse.

At present, military scientists have faced a number of serious technological barriers to the creation of LIPC. The plasma channel, which must be learned to keep stable at least for a short time and direct it at the same time to the target, self-destructs. In addition, there is a danger that during the formation of the channel and focusing the beam on the air, the energy will destroy the optical system of the laser and hit the shooters themselves.

It is necessary to reduce the load on the optical systems and keep it at a low level until a plasma channel is formed and energy flows to the target. There are also other problems, in particular the synchronization of the laser with high voltage, the creation of capacious power sources and a reliable field device, that is, the weapon itself. It is possible that a number of these problems will be solved using the most powerful NIF pulsed laser, which recently set a record for laser pulse power.

Apparently, the future plasma-laser gun will be quite large and will only fit on ships or trucks. However, the advantages that it promises on the battlefield will more than pay off the dimensions and huge power consumption.

It is possible that a number of these problems will be solved using the most powerful NIF pulsed laser, which recently set a record for laser pulse power.

Other interesting news:

▪ Self-driving cars from Google

▪ Off-road electric scooter RX200

▪ The doctor who is always with you

▪ The world's most powerful X-ray laser

▪ A chamber the size of a grain of salt

News feed of science and technology, new electronics

Interesting materials of the Free Technical Library:

▪ site section Frequency synthesizers. Selection of articles

▪ article Dear Shkap. Popular expression

▪ article How did the constellations get their names? Detailed answer

▪ article Work in clinical diagnostic laboratories. Standard instruction on labor protection

▪ article Enamel paints. Simple recipes and tips

▪ article A simple soldering iron tip temperature controller. Encyclopedia of radio electronics and electrical engineering

Leave your comment on this article:

All languages of this page

Home page | Library | Articles | Website map | Site Reviews