link=https://ar.wikipedia.org/wiki/%D9%85%D9%84%D9%81:Potenzialtrichter_Freileitung.svg|left|thumb|303x303px|Voltage between the two men: Here, a difference is formed in the voltage on the ground, passing an electric current between the two men. The greater the voltage difference, the more severe the effect on the person. (In that case, the step must be very, very shortened when moving away from the severed cable so that the voltage difference between the two legs is small. Since the discovery of its uses, electricity has become one of the most widely used motive energy sources. This resulted in a dependency and a close connection with the life of civilised people by using electricity in all activities. On the other hand, however, negligence in protecting against electricity exposes multiple effects on the human body and its surroundings.

Raised the passage of an electric current in the human body

When an alternating current passes through the human body, it has some characteristics that differ according to the current values:

• 0.5 to 1 (mA): Feeling threshold depending on skin condition.
• 8 (mA): Shock to the touch and a sudden reaction.
• 10 (mA): electric shock + muscle contraction, plus a continuous contraction.
• 20 (mA): electric shock and the onset of rib cage paralysis of the ribs.
• 30 (mA): electric shock and chest tetanus
• 40 (mA): electric shock + total tetanus.
• 70 to 100 (milliampere): electric shock, chest tightness and abdominal fibers shrinking plus burns
• 1000 (milliampere): sudden heartbeat, deep burns, and chemical breakdown of blood (non-reversible effects, meaning certain death).
• More than 1000 (milliamps): destroys nerve centers and internal chemical decomposition.

The effect of electrification duration

With a shock of 30mA and within 5 seconds, there are two possibilities to escape death. The same is the case if the shock in the human body is 300 mA but within a very short period of 0.5 seconds. There are two characteristics that explain the effect of time t in terms of current And voltage in the human body.

Current characteristic

link=https://ar.wikipedia.org/wiki/%D9%85%D9%84%D9%81:Effet_elec.png|thumb|The effect of the passage of electric current This characteristic shows the effect of time in the event of an electric shock: The figure below is divided into four regions and the L curve, which are:

• Zone 1: There is no reaction.
• Zone 2: No serious physiological trace.
• Zone 3: There is no organic damage, but there is a muscle contraction that prevents the individual from releasing the device.
• Zone 4: Pulses are dangerous, the consequences are dangerous, and accidents are fatal.
• Curve L: The curve L shows the boundaries of the safety zone, based on the rules NF C 15-100. In force in France since 2003.

Voltage or resistance property

link=https://ar.wikipedia.org/wiki/%D9%85%D9%84%D9%81:Effet-ten.png|thumb|The effect of time on applied voltage This feature shows the effect of time when a voltage is applied.

Resistance of the human body

link=https://ar.wikipedia.org/wiki/%D9%85%D9%84%D9%81:Effet-ris.png|thumb|مقاومة جسم الإنسان بدلالة الجهد The resistance of the human body in terms of effort

• Fatigue, health and human lifespan.
• Skin condition at the point of contact.
• Skin quality.
• Contact surface.
• The voltage applied at the point of contact.

The dangers of electricity

For the dangers arising from the different uses of the current, we summarise them in six elements, namely:

• Electrocution .
• electric shock
• An effort between the two men
• Burns
• Fire
• Loss of vision with the electric arc.
• Electric explosion.

Electrocution and electrocution

The electrical current that passes in the human body stimulates and contracts the muscles beyond the value of 15 milliamps (a lamp with a capacity of 40 watts is equivalent to 175 milliamps), which prevents us from freeing, and causes muscle contraction, difficulty breathing, and an acceleration of the heartbeat, which leads to death.

1. Thunderbolt

A thunderbolt is a vivid example of an electric shock, as it is an electrical charge that arises in the atmosphere as a result of a storm that discharges the lightning bolt directly from a mass of clouds in the ground in a lightning fashion. Its enormous density is estimated between 3000 amperes for the weak thunderbolt and more than 300000 amperes for the strong thunderbolt. About 30,000 amps. There is a constant feature that is the rapid emergence of currents of large intensity. Rapid changes of these large currents are the cause of electromagnetic wave radiation that travels in a vacuum as radio waves. A thunderbolt can be likened to a giant antenna. This strong electromagnetic radiation causes a great number of inconveniences that can lead to Destroying sensitive electrical equipment, despite not having direct contact with the lightning bolt.

2. The effects of lightning strike are classified into two groups: direct and indirect effects

• Direct effects

link=https://ar.wikipedia.org/wiki/%D9%85%D9%84%D9%81:Lightning_striking_the_Eiffel_Tower_-_NOAA.jpg|thumb|Direct impact of lightning A lightning bolt occurs when it directly touches objects, and an electrical current flows to the ground as it passes through the objects. (Tree, house, fence, electric line, etc. ...).

• Indirect effects

link=https://ar.wikipedia.org/wiki/%D9%85%D9%84%D9%81:7942a_-_Russett_-_Concord_Park.jpg|thumb|Indirect impact of thunderbolt It is the most present, and we can feel it from a distance, without the person being directly exposed to radiation and can be seen at great distances from the point of impact, and even without listening to thunder.

• Notice

It is often difficult to distinguish between these two effects, because in many cases the end result is the same, and it occurs over time.

Burns

The electric arc arises through a short circuit, which causes an increase in temperature and leads to severe burns and damage to eyesight .

The fire

The fire in the electrical circuit is caused by several causes, the most important of which are:

Vector high temperature

Whenever an electrical current passes (the circuit must be closed), the temperature of the devices used by the user increases, especially when its distance is not specified, since the electrical network is equipped with an adequate amount of energy, which leads to the opening of the electrical circuit and the increase in the temperature of the conductors. To prevent fire [?] In all electrical circuits, every line must be protected by a position (fuse or differential breaker). When the conductor temperature increases, the current is automatically cut off.

Damaged insulation

In this case, the electrical circuit is not protected, due to a fault in isolation, in any case in its primary stage, which can last for hours or days. Vector insulation error can be caused by damaged wires at the time of installation of lines, insulated wires that have been damaged by rodents or moisture ... etc. In all these cases, there is a loss of some current (0.3 amperes or some amperes), which is not sufficient for the fuse to be lost, but it is sufficient to cause a fire.

Poor communication

In addition to the insulation error, another fire risk remains that is not neglected because it is frequent, which is non-separable and incapable of melting? What is meant by poor contact in the fuse and the differential breaker as well as for the connection. Every time a bad contact (dilute the oxidation of the material) leads to heat when the current passes, weak at the beginning of time and more than that is important, the connection of the circuit breakers and sockets are always the object of experiment because the result is poor contact, followed by heating, which means fire.

Incorrect use of electrical appliances

It is considered another cause of frequent burns as it causes great material damage resulting from incorrect use of electrical appliances (lamps, electric heaters. What is known is that we sometimes ignore the intense glare of the lamp that causes fire with ease. We take a lamp with a capacity of 100 watts, the latter turning 97) % Of the energy consumed into heat and 3% of it into light. It is better to use the term electric heater that produces light. The opposite is true for water heaters, meaning that the temperature despite its accumulation does not cause any danger (as a maximum of 80 ° C). Electric heaters contain elements Indoor whose temperature exceeds 600 ° C.

When covered with inflammable materials such as: vectors, curtains, etc., their temperature can reach high values that cause these materials to ignite.

Loss of vision with the electric arc

link=https://ar.wikipedia.org/wiki/%D9%85%D9%84%D9%81:Arcing_pickup_shoe.jpg|thumb|Electric arc at London train station link=https://ar.wikipedia.org/wiki/%D9%85%D9%84%D9%81:Lichtbogen_3000_Volt.jpg|thumb|Electric arc An electric arc is a thermal light radiation created by opening two diamonds under pressure. Thanks to the electric current, an electric arc is created between the electrode and the piece to be welded. This electric arc allows the creation of a melt bath between the trace minerals and the base minerals in a liquid state, the latter producing a luminous beam called ultraviolet light.

Electric shock

link=https://ar.wikipedia.org/wiki/%D9%85%D9%84%D9%81:High_voltage_warning.svg|thumb|Electric shock alert panel

The explosion

In the presence of a vapor, gas flame or dust and fuel, a small spark is sufficient to cause a combustion or explosion and is often violent. In fact, the electric arc of the cutter and the coolant modifier, a battery bell breaker has sufficient energy to ignite this type of fuel.

preventive measures

1. When installing electrical wires for lighting purposes, they must be in insulated pipes from the inside, and they must not be left exposed so that moisture does not leak into them or the heat affects them and leads to an electrical short.
2. The cast wire must not be knotted to shorten it or hammered with nails to bring it closer to the walls and for the purpose of shortening the wire is cut to the required size.
3. The wires and cables used in the electrical connections must be suitable for the current passing through them and to connect the metal structures of the electrical appliances to the ground.
4. No electrical outlet should be overloaded, and upon noticing any hotness in the electrical switches or connections, inform the competent electrician to do the necessary, and no electrical connections or repairs shall be carried out without the knowledge of specialists in the field of electricity.
5. Connecting devices and equipment to a static ground complex suitable for discharging any shipments as soon as they are generated.
6. The wires and cables used in the electrical connections must be suitable for the current passing through them and to connect the metal structures of the electrical appliances to the ground.
7. No electrical outlet should be overloaded, and upon noticing any hotness in the electrical switches or connections, inform the competent electrician to do the necessary, and no electrical connections or repairs shall be carried out without the knowledge of specialists in the field of electricity.
8. When installing any electrical devices such as transformers, motors, electrical switches, or electrical circuits anywhere, these devices must be in a safe condition as well.
9. Any possibility of sudden touching of the current carrying conductors shall be prevented.
10. The electrical appliances must be placed in the least possible area or in a special room thereof, and if placed in the open they must be covered with protective barriers to prevent approaching them.
11. Warning instructions must be placed next to the devices and connectors carrying electric current, indicating the amount of voltage passing through these devices, especially in devices that carry a current of high pressure. These instructions should be clear and easy to read.
12. Those in charge of maintenance work for electrical appliances must be technical workers, and no repairs or installations in electrical appliances should be carried out except after making sure that the electrical current does not pass through them and connect them to the ground. And must use the appropriate personal protective missions.
13. Regular maintenance of electrical appliances must be carried out, and upon discovering any damage or any risks, the damage shall be repaired and the causes of the hazards removed immediately.
14. Electrical wires covered with rubber or plastic should not be exposed to the sun or heat, so as not to damage the rubber if exposed for a long time.
15. Colored papers or ribbons should not be affixed to wires in celebrations or for the purpose of decoration, so as not to be a cause of fire from any sparks that occur or as a result of their contact with a hot lamp.
16. The placement of piston boxes (fuses) and distribution panels must take into account that they are outside the rooms that contain fumes, dust, or inflammable materials or gases.
17. A piston box (fuses) must be assigned to each group of connections and a knife to cut off the current in an emergency, and an automatic electrical breaker must be used to separate the electricity in the event of an electric arc.
18. The switches used inside the chemical warehouse shall be of the special spark-insulated type.
19. The electrical current must be cut off to all establishments in the event of evacuation, such as workshops and stores after the end of working hours, and when leaving the house for a long period such as travel, for example, the electrical current must be disconnected from the house.
20. It is strictly forbidden to connect or install (diodes) or electrical switches in walls and ceilings or any material directly conductive to the current because there is always a strong possibility that the wires behind these diodes or switches are not well insulated, so they are exposed to moisture and result in a short circuit and thus cause a fire.

Read also

• Electricity
• An effort between the two men

[[Category:Electricity]]