Classification of electrical installations and electrical equipment. What is an electrical installation Alphanumeric code of climatic modification

These rules are binding on all consumers of electricity, regardless of their departmental affiliation. These rules apply to existing electrical installations of consumers.

What does the term "electrical safety" mean?

Electrical safety is a system of organizational and technical measures and means to protect people from harmful and dangerous effects of electric current, electric arc, electromagnetic field and static electricity.

What does the term electrical installation mean?

Electrical installations are a set of machines, apparatus, lines and auxiliary equipment (together with the structures and rooms in which they are installed) intended for the production, transformation, transformation, transmission, distribution of electrical energy and its transformation into another type of energy. Electrical installations under the terms of electrical safety are subdivided into electrical installations with voltages up to 1000 V and electrical installations with voltages above 1000 V. Electrical installation of a building is a set of interconnected electrical equipment within a building.

What electrical installations are considered valid? Voltage classification of electrical installations?

Operating electrical installations are those installations that contain sources of electricity (chemical, galvanic and semiconductor elements), which are fully or partially energized, or which can be energized at any time by switching on the switching equipment. Under the terms of electrical safety, electrical installations are divided into electrical installations with voltages up to 1000 V inclusive and electrical installations with voltages above 1000 V.

Give a description of the electrical rooms.

Electrical premises are premises or, for example, fenced off with nets, parts of the premises that are accessible only to qualified service personnel, in which electrical installations are located. Dry rooms are rooms in which the relative humidity does not exceed 60%. Humid rooms - the relative humidity in them is more than 60%, but does not exceed 75%. Damp rooms - the relative humidity in them for a long time exceeds 75%. Especially moist - the relative humidity is close to 100%. Hot - the temperature in them exceeds constantly or periodically (more than 1 day) + 35 ° С. In dusty rooms, according to production conditions, technological dust is emitted in such an amount that it can settle on wires, penetrate into machines and devices. Rooms with a chemically active or organic environment constantly or for a long time contain aggressive vapors, gases, liquids, deposits or mold are formed that destroy the insulation of electrical equipment.

What categories are the premises divided into with regard to the risk of electric shock to people?

With regard to the danger of electric shock to people, a distinction is made between: Rooms without increased danger, in which there are no conditions that create an increased or special danger. Premises with increased danger, which are characterized by the presence in them of one of the following conditions that create an increased danger: - damp, - conductive dust, - conductive floors (metal, earth, reinforced concrete, brick, etc.), - high temperature, - possibility simultaneous touch of a person to metal structures connected to the ground, technological devices, on the one hand, and to the metal cases of electrical equipment, on the other. Particularly dangerous premises, which are characterized by the presence of one of the following conditions that create a particular danger: special dampness, chemically active or organic environment, simultaneously two or more conditions of increased danger. The territories for the location of outdoor electrical installations in relation to the risk of injury to people by electric shock are equated to especially dangerous rooms.

Zeroing, purpose and principle of operation.

Zeroing is a deliberate electrical connection with a neutral protective conductor of metal non-current-carrying parts that may be energized due to a short circuit to the case and for other reasons. The task of grounding is to eliminate the danger of electric shock in case of touching the body and other non-current-carrying metal parts of the electrical installation that are energized due to a short circuit to the body. This problem is solved in a different way than with protective grounding: by quickly disconnecting the damaged electrical installation from the network. However, since the housing turns out to be grounded through the neutral protective conductor, then during the emergency period, i.e. from the moment a short circuit occurs on the case and until the unit is disconnected from the mains, the protective property of this grounding manifests itself, similarly to how it occurs with protective grounding. The principle of operation is grounding - the transformation of the short circuit to the case into a single-phase short circuit (i.e., a short circuit between the phase and neutral wires) in order to cause a large current that can ensure the operation of the protection and thereby automatically disconnect the damaged installation from the supply network. Such protection are: fuses or overcurrent devices installed in front of electricity consumers to protect them from short-circuit currents; magnetic starters with built-in thermal protection, designed for remote starting and stopping of electric motors; contactors in combination with a thermal relay, protecting the consumer from overload; and, finally, automatic devices with combined releases, protecting consumers simultaneously from short-circuit currents and from overload. The field of application of grounding is three-phase four-wire networks up to 1000 V with a solidly grounded neutral. Usually these are 380/220 V and 220/127 V networks, as well as 660/380 V networks.

What is called a protective conductor?

A protective conductor (PE) in electrical installations is a conductor used to protect people and animals from electric shock. In electrical installations up to 1000 V, the protective conductor connected to the grounded neutral of the generator or transformer is called the neutral protective conductor.

Which conductor is called a zero worker?

The zero working conductor (N) in electrical installations up to 1000 V is a conductor used to power electrical receivers, connected to a grounded neutral of a generator or a transformer in three-phase current networks, with a solidly grounded output of a single-phase current source, with a solidly grounded source point in three-wire DC networks.

For what purpose should grounding devices be built and metal parts of electrical equipment grounded?

To ensure the safety of people in a power plant with an insulated net, in accordance with the requirements of the Rules for the Installation of Electrical Installations, grounding devices must be built, to which the bodies of electrical equipment are reliably connected, which, due to insulation failure, may be energized.

What parts of electrical installations and electrical equipment are subject to grounding or grounding?

Parts subject to grounding or grounding include: - housings of electrical machines, transformers, apparatus, lamps, etc .; - drives of electrical devices; - secondary windings of measuring transformers; - frames of switchboards, control panels, panels and cabinets; - metal structures of switchgears, metal cable structures, metal cases of cable joints, metal sheaths and armor of control and power cables, metal sheaths of wires, steel pipes for electrical wiring and other metal structures associated with the installation of electrical equipment; - metal cases of mobile: and portable electrical receivers.

Protective grounding, purpose and scope?

Purpose and scope. Protective grounding is a deliberate electrical connection to the ground or its equivalent of metal non-current-carrying parts that may be energized due to a short circuit to the case and for other reasons (inductive influence, potential removal), etc. A short to the case, or more precisely, an electrical short to the case, is an accidental electrical connection of a live part with metal non-live parts of an electrical installation. A short circuit to the case can result, for example: accidental touching the live part of the machine body, damaged insulation, falling of a live wire on the specified metal non-conductive parts, etc. The task of protective grounding is to eliminate the danger of electric shock in case of touching the body and other non-current-carrying metal parts of the electrical installation that are energized. The area of ​​application of protective grounding is three-phase networks up to 1000 V with isolated net and above 1000 V in any neutral mode. Protective grounding should be distinguished from the so-called working grounding - a deliberate electrical connection to the ground of individual points of the electrical network (for example, neutral point, phase conductor, etc.), which is necessary for the proper operation of the installation under normal or emergency conditions. Working grounding is carried out directly or through special devices - breakdown fuses, arresters, resistors, etc.

What are the rules for installing grounding?

Grounding is installed on the live part immediately after checking the absence of voltage. The portable ground is first connected to the grounding device, and then, after checking the absence of voltage, is installed on the live parts. Remove the portable ground in the reverse order; first from live parts, and then disconnected from the grounding device. Installation and removal of portable grounding is carried out in dielectric gloves using an insulating rod in electrical installations above 1000 V. Clamps of portable grounding are fixed with the same rod or directly with your hands in dielectric gloves. It is forbidden to use conductors for grounding that are not intended for this purpose, as well as to connect grounding by twisting them. It is allowed, in cases where the cross-section of cable conductors does not allow the use of portable grounding, for electric motors up to 1000V, it is necessary to ground the cable line with a copper conductor with a cross-section of at least the cross-section of the cable conductor, or connect the cable conductors together and isolate them. Such grounding or connection of cable cores is taken into account in the operational documentation along with portable grounding.

How is the connection of grounding and neutral protective conductors carried out?

The connection of grounding and zero protective conductors to grounding conductors, the grounding loop to grounding structures is carried out by welding, and to the bodies of devices, MACHINES and overhead lines - by welding or a reliable bolted connection. Each part of an electrical installation subject to grounding or grounding is connected to the grounding or grounding network using a separate conductor. Consecutive connection to the grounding or neutral protective conductor of the grounded or neutralized parts of the electrical installation is prohibited. Grounding and neutral protective conductors must be coated to prevent corrosion.

How are electrical receivers carried out? grounding or grounding of portable

Earthing or neutralization of portable electrical receivers is carried out by a special conductor (the third - for single-phase and direct current electrical receivers, the fourth - for three-phase electrical receivers), located in the same shell with the phase conductors of the portable wire and connected to the "body" of the electrical receiver and to a special contact of the plug-in connection plug. The cross-section of this core must be equal to the cross-section of the phase conductors. The use of a neutral working conductor for this purpose, including one located in a common shell, is not allowed. The conductors of wires and cables used for grounding or grounding of portable electrical receivers must be copper, flexible, with a cross section of at least 1.5 mm sq. for portable electrical receivers in industrial installations and not less than 0.75 mm sq. for household portable electrical receivers.

What applies to electrical protective equipment?

Electrical protective equipment includes: - insulating rods of all types (operational, measuring, for grounding); - insulating and electrical clamps; - voltage indicators of all types and voltage classes (with a gas-discharge lamp, contactless, pulse type, with an incandescent lamp, etc.); - contactless signaling devices of voltage presence; - insulated tool; - dielectric gloves, boots and galoshes, carpets, insulating under stakes; - protective fences (shields, screens, insulating linings, caps); - portable grounding; - devices and devices for ensuring labor safety when conducting tests in measurements in electrical installations (voltage indicators for checking the phase coincidence, devices for puncturing a cable, a device for determining the voltage difference in transit, indicators of cable damage, etc.), - posters and signs security; - other protective equipment, insulating devices and devices for repair work under voltage of 110 kV and above, as well as in power grids up to 1000 V (polymer and flexible insulators; insulating ladders, ropes, inserts of telescopic towers and lifts; rods for transferring and equalizing potential; flexible insulating covers and linings, etc.).

What is called the main electrical protective agent?

The main electrical protective device is called an insulating electrical protective device, the insulation of which can withstand the operating voltage of the electrical installation for a long time and which allows you to work on live parts that are energized. The main electrical protective equipment is made of insulating materials (porcelain, ebonite, getinax, wood-laminated plastics, etc.). Moisture-absorbing materials (bakelite, wood, etc.) must be coated with a moisture-resistant varnish and have a smooth surface without cracks, delamination and scratches.

What applies to electrical installations above 1000 V? the main electrical protective equipment in

The main electrical protective equipment in electrical installations with voltages above 1000 V include: - insulating rods of all types; - insulating and electrical measuring pincers; - voltage indicators; - devices and devices for ensuring labor safety during tests and measurements in electrical installations (voltage indicators for checking phase coincidence, devices for cable puncture, cable damage indicators, etc.); - other protective equipment, insulating devices and devices for repair work under voltage in electrical installations with a voltage of 110 kV and above (polymer insulators, insulating stairs, etc.)

What is the main electrical protective equipment in electrical installations up to 1000 V?

The main electrical protective equipment and electrical installations with voltage up to 1000 V include: - insulating rods; - insulating and electrical measuring pincers; - voltage indicators; - dielectric gloves; - an insulated tool.

What is called an additional electrical protective device?

An additional electrical protective device is called an insulating electrical protective device, which by itself cannot provide protection against electric shock at a given voltage, but complements the basic protection device, and also serves to protect against touch voltage and step voltage.

What applies to additional electrical protective equipment in electrical installations Above 1000 V?

Additional electrical protective equipment in electrical installations with voltages above 1000 V include: - dielectric gloves; - dielectric bots; - dielectric carpets; - insulating supports and pads; - insulating caps.

What applies to additional electrical protective equipment for electrical installations up to 1000 V?

Additional electrical protective equipment for electrical installations up to 1000 V includes: - dielectric galoshes; - dielectric carpets; - insulating supports and pads; - insulating caps.

How are posters and safety signs classified?

Safety posters and signs are used to: - prohibit actions with switching devices (prohibiting); в в - warning of the danger of approaching live parts that are energized (warning); - permission of certain actions only when specific labor safety requirements are met (warning), - indication of the location of various objects and devices (indicative). Prohibiting: "DO NOT TURN ON! PEOPLE WORK". "DO NOT SWITCH ON! OPERATION ON THE LINE", "DO NOT OPEN! PEOPLE WORK", "HAZARDOUS ELECTRIC FIELD WITHOUT PROTECTION PROHIBITED", "OPERATION UNDER VOLTAGE DO NOT RE-ON". Warning signs: "WARNING! ELECTRIC VOLTAGE" sign and posters "STOP! VOLTAGE", "TEST HAZARDOUS TO LIFE", DO NOT TAKE IN! KILL ". Prescribing:" WORK HERE "," GET IN HERE. "Indicative:" EARTHED ".

What is the procedure for the maintenance and storage of electrical protective equipment in electrical installations with voltages up to and above 1000 V?

Electrical protective equipment in operation and in stock must be stored and transported under conditions that ensure their serviceability and suitability for: use without prior restorative repair, therefore protective equipment must be protected from moisture, pollution and mechanical damage. Electrical protective equipment made of bakelite, plastic materials, ebonite, wood should be stored indoors. Electrical protective equipment made of rubber in operation must be stored in closed rooms, in special cabinets, on racks, in boxes, etc., separately from the tool. They must be protected from oil, gasoline, direct sunlight. Spare electrical protective equipment made of rubber should be stored in a heated, dark, dry room at a temperature of O ... 5 ° C. Isolation rods are stored in an upright position suspended or installed in risers without contact with the wall. Storage of rods in a horizontal position is allowed. In this case, the possibility of their deflection must be excluded. The insulating pliers are stored on special shelves so that they do not touch the walls. Voltage gauges and clamp meters should be kept in their cases. Isolation Devices and Appliances for Live Work: Isolating ladders, platforms and other similar devices are stored in designated locations where they are protected from moisture and dust.

What are the general rules for the use of electrical protective equipment used in electrical installations with voltages up to and above 1000 V?

The use of electrical protective equipment is made for their intended purpose in electrical installations with a voltage not higher than that for which they are designed. All main electrical protective equipment is designed for use in closed or open switchgears and on overhead lines only in dry weather. Therefore, the use of these products outdoors and in damp weather (during rain, snow, frost, fog) is prohibited. At the same time, means of a special design are used, which are designed to work in such conditions. Before each use of electrical protective equipment, the personnel must: - check its serviceability and the absence of external damage, clean and wipe off dust, check rubber gloves for punctures; - check on the stamp for what voltage the use of this agent is permissible and whether the period of its periodic testing has expired. It is prohibited to use protective equipment, the test period of which has expired, since such means are considered unsuitable.

What is the damaging effect of electric current on the human body?

The biological effect of electric current on the human body, which is under tension, is manifested in the convulsive contraction of various muscle groups, including the muscles that carry out the respiratory movement of the chest and regulate the work of the heart. The greatest danger is a violation of cardiac activity due to the occurrence of cardiac fibrillation, which is characterized by a multi-temporal uncoordinated contraction of individual fibers of the heart muscle, leading to a violation of the rhythmic contraction of the heart OR even to its paralysis. The type of electric shock to a person, in which breathing is disturbed and the heart does not pulsate, is called an electric shock. The degree of the physiological effect of an electric current is mainly determined by its type and magnitude, the duration of the flow and depends on the path of the current through the human body and the individual properties of a person. The most likely path is hand-hand, hand-foot, foot-foot. In addition, injury can occur without direct current flow through the human body as a result of burns caused by an open electric arc.

What voltage is considered dangerous to human life? What amount of current is considered fatal to humans?

There is still no established point of view regarding the magnitude of the "allowable" or "safe" voltage, since the electrical resistance of a person varies widely depending on specific conditions. Therefore, different countries regulate their own standards. For example, in France, 24 V AC and 50 V DC are accepted. In our practice, depending on the environmental conditions, it is assumed that the allowable voltage is up to 50 VAC. However, even these voltages cannot be regarded as ensuring complete safety. For example, the literature describes cases of fatal injury to a person with a voltage of 12 V and below. A dangerous value of the current flowing through the human body should be considered 10 mA, lethal - 100 mA.

What are the types of burns?

Burns are thermal - caused by fire, steam, hot objects and substances, chemical - acids and alkalis, and electrical - by the action of an electric current or an electric arc. According to the depth of the lesion, all burns are divided into four degrees: - the first - redness and swelling of the skin; - the second - water bubbles; - third, necrosis of the superficial and deep layers of the skin; - the fourth - charring of the skin, damage to muscles, tendons and bones.

What determines the danger to a person when an electric current passes through him?

The magnitude of the current passed through the body, the time a person was under an electric current, the frequency of the current, the individual properties of a person.

What is the sequence for providing first aid to victims of electric shock?

The sequence of first aid is as follows: - eliminate the impact on the body of damaging factors that threaten the health and life of the victim (free from the action of electric current, extinguish burning clothes, etc.), assess the condition of the victim; - to determine the nature and severity of the injury, the greatest threat to the victim's life and the sequence of measures to save him; - carry out the necessary measures to save the victim in order of urgency (restore airway patency, administer artificial respiration, external heart massage, stop bleeding, etc.); - to support the basic vital functions of the victim until the arrival of a medical worker; - call an ambulance or a doctor, or take measures to transport the victim to the nearest medical facility. The salvation of the victim from the action of the electric current in most cases depends on the speed of his release from the current, as well as on the speed and correctness of rendering assistance to him. Delay in its submission may result in the death of the victim.

What are the types of electric shock?

Electric shock causes damage to the internal organs of a person (paralysis of the heart, respiratory paralysis); electrical injuries, damage to external parts of the body.

What are the rules for freeing a victim from electric shock?

If the victim comes into contact with live parts, it is necessary, first of all, to free him from the action of the electric current. It should be borne in mind that touching an electrified person without proper precautions is life-threatening for the person providing assistance. Therefore, the first action of the person providing assistance should be to quickly disconnect that part of the installation to which the victim is touching. In this case, the following must be taken into account: - if the victim is at a height, disconnecting the installation and releasing him from the electric current can lead to the victim falling from a height, therefore, measures must be taken to ensure the safety of the victim's fall; - when the installation is turned off, the electric lighting can also turn off at the same time, in connection with which it is necessary to provide lighting from another source, without delaying, however, the disconnection of the installation and the provision of assistance to the victim. If the shutdown of the installation cannot be done quickly enough, it is necessary to take measures to separate the victim from the live parts to which he touches. In this case, you should use dry clothing, a rope, a stick, a board or some other dry object that does not conduct an electric current. The use of metal or wet objects for these purposes is not allowed. When separating the victim from live parts, it is recommended to act with one hand as much as possible. To separate the victim from the ground or live parts that are energized above 1000V, you should wear dielectric gloves and boots and act with a barbell or pliers designed for the voltage of this electrical installation.

How is first aid provided to an electric shock victim?

First aid measures depend on the condition in which the victim is. To determine this condition, it is necessary to immediately carry out the following measures (time no more than 1 min.): - lay the victim on his back on a hard surface; check for the presence of breathing in the victim (determined by the rise of the chest); - check if the victim has a pulse; - find out the state of the pupil (narrow or wide) - a wide pupil indicates a sharp deterioration in the blood supply to the brain. In all cases of electric shock, calling a doctor is mandatory, regardless of the condition of the victim. If it is not possible to quickly call a doctor, it is necessary to urgently deliver the victim to a medical institution, provide the necessary vehicles or stretchers for this. In the event of an electric shock, the victim may be conscious or unconscious. If the victim is conscious, then he should be laid in a comfortable position and ensure complete rest until the doctor arrives. If the victim is unconscious, then immediately unfasten the clothes, create an influx of fresh spirit, give ammonia to sniff, spray it with water and do artificial respiration.

How is artificial respiration (ventilation) performed?

Artificial respiration is performed in cases where the victim does not breathe or breathes very badly (rarely, convulsively, as if by sobbing), and also if his breathing is constantly deteriorating. The most effective method of artificial respiration is "mouth-to-mouth" or "mouth-and-nose" method, as this assesses the supply of a sufficient volume of air to the victim's lungs. Air blowing is carried out through gauze, a scarf, a special device - an air duct. The victim is placed on his back, the clothes are unbuttoned, the upper respiratory tract, which is closed by the sunken tongue, is provided, and the oral cavity is freed from foreign bodies. The caregiver leans towards the victim's face, takes a deep breath with his open mouth, completely covers the victim's open mouth with his lips and exhales vigorously, blowing air into his mouth with some effort, while simultaneously covering the victim's nose with his cheek or fingers. In this case, it is imperative to observe the victim's chest, which rises. As soon as the chest has risen, the air injection is stopped, the assisting person turns his face to the side, and the victim exhales passively. If the victim has a well-defined pulse and only artificial respiration is needed, then the interval between artificial breaths is 5 s. (12 breaths per minute). For small children, air is blown into the mouth and nose at the same time, covering the child's nose and mouth with their mouths. The smaller the child, the less air he needs to inhale and the more often the inhalation should be carried out in comparison with an adult (up to 35.18 times per minute). Artificial respiration is stopped after the victim has restored sufficiently deep and rhythmic spontaneous breathing.

How is an external heart massage performed?

In case of electric shock, not only respiratory arrest can occur, but blood circulation can also stop when the heart does not circulate blood through the vessels. In this case, artificial respiration alone when providing assistance is not enough: since oxygen from the lungs cannot be carried by blood to other organs and tissues, it is necessary to resume blood circulation by artificial means. If you press on the sternum, the heart will be compressed between the sternum and the spine and blood will be squeezed out of its cavities into the vessels. If you press on the sternum with jerky movements, then the blood will be pushed out of the cavities of the heart in much the same way as it happens with its natural contraction. This is called an external heart massage, which artificially restores blood circulation. Thus, when artificial respiration is combined with external heart massage, the functions of respiration and blood circulation are imitated. The complex of these measures is called resuscitation, and the measures are called resuscitation.

What are the conditions for using portable power tools and hand-held electric machines in different rooms?

In rooms without increased danger and in rooms with increased danger, it is allowed to use equipment of class I under the following conditions: - use of at least one of the electrical protective equipment (dielectric gloves, carpets, stands, galoshes); - without the use of electrical protective equipment, if the machine or tool, with only one electrical receiver, receives power from an isolation transformer, an autonomous motor-generator set, a frequency converter with separate windings or through an RCD; - class II, III - without the use of electrical protective equipment. It is not allowed to use class I equipment in especially hazardous rooms, outdoors (outdoor work), equipment of class II, III is allowed to be used without electrical protective equipment. In the presence of particularly unfavorable conditions (in vessels, apparatus and other metal containers with limited movement and exit), equipment of class I is not allowed, equipment of class II is allowed to be used using one of the electrical protective equipment (dielectric gloves, carpets, stands, galoshes), and also without the use of electrical protective equipment, if the machine or tool, with only one electrical receiver, is powered by an isolation transformer, an autonomous motor-generator set, a frequency converter with separating windings or through an RCD, class III equipment - without the use of electrical protective equipment.

At what voltage should a portable power tool be used?

Portable electrical receivers should be powered from a network with a voltage of no more than 380/220 V. Depending on the category of the room according to the level of danger of electric shock to people, portable electrical receivers can be powered either directly from the network, or through isolation or step-down transformers. Metal enclosures of portable power consumers with voltages above 50 V AC and above 60 V DC in all rooms AND outdoor installations must be grounded or grounded, except for power consumers with double insulation or powered by isolation transformers.

What is prohibited for persons using a power tool?

Persons using power tools and hand-held electric machines are prohibited from: - transferring hand-held electric machines and power tools at least temporarily to other persons; - disassemble hand-held electric machines into a power tool and carry out any repairs themselves (both the power tool itself or a hand-held electric machine, and the wires of plug connections, etc.); - hold on to the wire of a hand-held electric machine or power tool or touch a rotating cutting tool; - remove shavings or sawdust with your hands during operation until the manual electric machine comes to a complete stop; - to work from ladders, to perform work at a height, strong scaffolding or scaffolds must be arranged, - to bring inside the drums of boilers, metal tanks, etc., etc. portable transformers and frequency converters; - leave hand-held electric machines and power tools unattended and plugged into the network.

What should be checked before starting work with a hand-held power tool?

Before starting work with hand-held electric machines, hand-held lamps and power tools, you should: - check the completeness and reliability of fastening parts; - check by external inspection of the serviceability of the cable (cord) to the plug; the integrity of the insulating parts of the body, handle and brush holder covers; the presence of protective covers and their serviceability; - checking the accuracy of the switch; - checking the operation at idle code; - for machines of class I, check the serviceability of the grounding circuits (between the machine body and the grounding contact of the plug); perform (if necessary) testing of the residual current device. Hand-held electric machines, hand-held lamps, power tools and auxiliary equipment for them, which have defects, are prohibited to be issued for work.

How to arrange the wires or cables of a portable power tool?

When using power tools, hand-held electric machines and hand-held lamps, their wires or cables should be suspended whenever possible. Direct contact of wires or cables with hot, wet and oily surfaces or objects is not allowed. If any malfunctions are found, work with hand-held electric machines, portable power tools and lamps is immediately stopped.

Qualification groups for persons serving electrical installations.

The 1st group is assigned to electrical personnel who have not passed the knowledge test according to these rules, personnel servicing electrical installations, personnel working with power tools, drivers of cars and truck cranes, cleaners of electrical installations. At the same time, the persons of the 1st group do not have special electrical training, but they have an elementary idea of ​​the danger of electric current and safety measures when working in the serviced area, electrical equipment, and installation. Persons of the 1st group should have practical acquaintance with the rules of first aid.

The 2nd group is assigned to trainees of institutes, technical schools, technical and vocational schools, electricians, electrical fitters, signalmen, electric motor operators, electric transport operators, crane operators, electric welders, and electrician practitioners (work experience of at least 1 month). Persons of the 2nd group should have: elementary technical acquaintance with electrical installations, a clear idea of ​​the danger of electric current and proximity to live parts, knowledge of basic precautions when working in electrical installations, practical acquaintance with the rules of first aid.

The 3rd group is assigned to electricians, electricians, signalmen, operational personnel of e-mail. substations, operational and repair personnel of electrical installations, trainees of institutes and technical schools, novice engineers and technicians, while work experience on electrical installations must be at least 6 months.

Persons of the 3rd group must have: basic knowledge in electrical engineering and familiarity with the device and maintenance of electrical installations, a clear understanding of the dangers when working in electrical installations, knowledge of general safety rules and rules for admission to work in electrical installations, knowledge of special safety rules for those types work that are part of the duties of this person, the ability to supervise those working in electrical installations, knowledge of the rules for providing first aid and the ability to provide first aid to the victim.

The 4th group is assigned to electricians, electrical fitters, signalmen, operating personnel of power plants, operating and repair personnel of shop electrical installations, novice engineers and technicians, safety engineers (work experience in the previous group is at least 1 year). Persons of the 4th group must have: knowledge in electrical engineering in the amount of a specialized vocational school, a complete understanding of the dangers when working in electrical installations, knowledge of these rules, as well as the rules for the use and testing of protective equipment used in electrical installations, knowledge of the installation so that you can freely understand which elements must be disconnected for the production of work, to find in nature all these elements and check their implementation and the necessary safety measures, the ability to organize the safe conduct of work and monitor them in electrical installations with voltages up to 1000 V, knowledge of the rules of first aid and the ability practically provide first aid to the victim (techniques of artificial respiration, etc.).

The 5th group is assigned to electricians, electrical fitters, craftsmen, technicians and engineers - trainees (total work experience is at least 5 years, for persons with an education of 7 grades and above, who have completed special training, as well as for persons who graduated from vocational and technical schools, general experience at least 3 years). Masters, technicians, engineers (with completed secondary or higher technical education) - total experience of at least 6 months. Age is not younger than 19 - 21 years old. Persons of the 5th group must have knowledge of the schemes and equipment of their site, solid knowledge of these rules both in general and in special parts, as well as the rules for the use and testing of protective equipment used in electrical installations, a clear idea of ​​what caused the requirement or another item, the ability to organize the safe production of work and supervise them in electrical installations of any voltage, knowledge of the rules for providing first aid and the ability to practically provide first aid (artificial respiration techniques, etc.), the ability to train personnel of other groups in safety rules and first aid.

Classification of electrical installations for electrical safety

Electrical installations are such installations in which electricity is produced, converted and consumed. They are divided into electrical installations up to 1000V and above 1000V.

Electrical rooms are premises or parts of a room that are fenced off (for example, with grids), accessible only to service personnel, in which electrical installations in operation are installed. By the nature of the environment, the premises are divided into the following types:

Dry, in which the relative humidity does not exceed 60%. In the absence of conditions in such rooms that characterize "hot rooms", "dusty rooms", "rooms with a chemically active environment", they are called normal.

Humid, where vapors or compensating moisture are released only temporarily and in small quantities, and the relative humidity is more than 60%, but not higher than 75%.

Raw, in which the relative humidity of the air exceeds 75% for a long time.

Especially damp, in which the relative humidity of the air is close to 100% for a long time (the ceiling, wall, floor and objects in the room are covered with moisture).

Hot, where the temperature for a long time exceeds 30 ◦ C.

Dusty, in which, according to production conditions, technological dust is emitted in such an amount that it can settle on wires, penetrate into machines, apparatus, etc.; Dusty rooms are divided into rooms with conductive and non-conductive dust.

Room with conductive floors - a room with metal, earth, reinforced concrete, brick, etc. by sex

Rooms with a chemically active environment, where, according to production conditions, vapors are constantly or for a long time, or deposits are formed that act destructively on the insulation and live parts of electrical equipment.

Premises that pose a risk of electric shock to people are divided into three categories.

Especially dangerous. Characterized by: special dampness, chemically active environment, the simultaneous presence of two or more conditions of increased danger.

Particularly dangerous premises are the majority of industrial premises, including all workshops of power plants, battery rooms, cable wells, telephone exchange shafts, etc. In these rooms, the operating voltage and local (work) lighting are selected as 12V. When using insulating protective equipment in these rooms, you can work with tools and lamps with a voltage of 42 (36) V. The source of reduced voltage 42 and 12V are, as a rule, special step-down transformers, which have a high resistance between the primary and secondary windings. They are powered from a 380/220 V network and are connected through an RCD (residual current device) to exclude the risk of electric shock to a person in the event of voltage appearing on the transformer case or when the high voltage passes to the 42 or 12V winding, the transformer case and one of the terminals (or neutral at three-phase voltage) must be grounded.

In addition, the plugs of low voltage pantographs must not fit into larger outlets.

With increased danger. They are characterized by the presence of one of the following signs: dampness, high temperature, conductive dust, conductive floors (metal, earthen, reinforced concrete, brick), the possibility of simultaneous touch of a person to the metal structures of buildings connected to the ground, technological devices, mechanisms, on the one hand, and to metal enclosures of electrical equipment - on the other.

Examples of rooms with increased danger are stairwells with conductive floors, metal machining workshops, telephone exchanges, radio and television workshops, etc. A voltage of 42 (36) V is used in these rooms. When using insulating protective equipment in these rooms, you can work with tools and lamps with a voltage of 220V. In all cases, the case of pantographs with voltages above 42 (36) V must be grounded or grounded.

3. Without increased danger. Premises in which there are no conditions of increased and special danger. An example of such rooms is dry, dust-free rooms with normal air temperatures, non-conductive floors and no grounded metal structures. In these rooms, a voltage of 220V is used for tools and lamps.

An electrical installation according to PTEEP is a complex of interconnected equipment and structures designed for the production or transformation, transmission, distribution or consumption of electrical energy. Here are the main types of electrical installations described in the normative and technical documentation.

Under the terms of electrical safety, electrical installations are divided into:
- electrical installations with voltage up to 1000V
- electrical installations with voltage over 1000V

By the type of current, electrical installations are divided into:
- DC power plants
- AC power plants

Classification of electrical installations according to the conditions of electrical safety of the room:

With increased danger
Dampness (relative humidity of air for a long time exceeds 75% and above)
Conductive dust
Conductive floors (metal, earth, reinforced concrete, brick, etc.).
High temperature (under the influence of various heat radiation, the temperature is constantly or periodically "more than 1 day" + 35 * С);
Possibility of simultaneous touch of a person to the metal structures of buildings, technological devices, mechanisms, etc. having a connection to the ground. on the one hand, and to the metal enclosures of electrical equipment, on the other.

Especially dangerous
Particular dampness (the relative humidity of the air is close to 100% - the ceiling, walls, floor, objects in the room are covered with moisture);
Chemically active or organic medium;
Simultaneously, two or more conditions of increased danger.

No increased danger
The latter include electrical rooms in which all conditions of increased danger are absent exclusively.

Classification of electrical installations by purpose:
- general purpose
-special purpose (tropical version, cold-resistant, moisture-resistant, chemically resistant).

Security classification of electrical installations:
-open (not protected from touching moving and live parts)
-protected (from accidental touching its moving and live parts from accidental ingestion of foreign objects and dust)
- waterproof
-splash-proof
-drip-proof
-dustproof
- closed (protected electrical equipment, designed so that the possibility of communication between its internal space and the environment can only take place due to loose connections between parts of electrical equipment or through separate small openings)
-sealed (protected, made in such a way that the possibility of communication between its internal space and the environment is excluded)
-explosion-proof (electrical equipment in which constructive measures are provided for the purpose of eliminating or hindering the possibility of ignition of the surrounding explosive atmosphere)

We have indicated only some of the methods for classifying electrical installations, which are described in the regulatory and technical documentation. It is permissible to classify electrical installations according to other parameters.

© All materials are protected by copyright law of the Russian Federation and the Civil Code of the Russian Federation. Full copying is prohibited without the permission of the resource administration. Partial copying is allowed with direct link to the source. The author of the article: a team of engineers of JSC "Energetik LTD"

Since during operation a number of controversial questions arise about what equipment can be defined as an operating electrical installation, it is worth considering in detail the main regulatory documents PTEEP and PUE. The first of which is decisive in terms of operating standards, and the second sets requirements for installation and design.

Definition

In general, the concept of an electrical installation includes all kinds of elements in which the transmission, transformation, distribution and subsequent consumption of electricity can occur. And under an operating electrical installation should be understood not only those devices, lines or structures through which electric current flows or into which voltage is applied, but also all that are currently disconnected, but voltage may arise on them. In this case, the way the voltage appears on the electrical installation does not matter, it can be:

• switching switching devices;
• being near the equipment creating;
• the intersection of power lines in the vertical plane with other lines.

Therefore, to transfer an existing electrical installation to the category of inoperative, it is not enough just to turn off the switch or power switch. To do this, it is required to make it impossible for a potential to arise even with the presence, even without an electrical connection.

Appointment

Existing electrical installations are designed for the transmission and redistribution of electrical energy. Since modern consumers of electricity are characterized by a large number of sensitive devices with a wide variety of operating principles, electrical installations must also ensure a high quality of supplied energy. If we consider in detail the concept of electrical installation, then it includes not only devices for transmission and distribution, but also switching and protective devices. Therefore, another purpose is the timely shutdown of various categories of consumers and the supply of backup or second power supply.

Depending on the importance of powering the electrical circuit, three categories of consumers are distinguished:

• for the first category, a break of no more than the time required for automatic switching to the second or reserve power supply may be allowed;
• the second allows a break in power supply no longer than for the time of the departure of the brigade or manual input of the second source;
• the third allows a break in food for no more than a day, and for single apartments and houses two days, but no more than three times a year.

Classification

Depending on the parameter, existing electrical installations are divided into such types. According to the voltage level, devices up to 1000 V and above 1000 V are distinguished. Each of the categories includes all voltage levels within their limits.

Depending on the purpose, the following devices are distinguished:

• Power- are characterized by a large amount of power, flowing current, high voltage. They are used, as a rule, on an industrial scale for the operation of electrical networks and electrical substations.
• Converting- designed to convert one kind of current into another. They are used in a wide variety of areas.
• Commutation- are intended for making switchings in the electrical circuit from high-voltage to household.
• Electro-operating- auxiliary equipment that can perform any technological operations (heating, movement, etc.).
• Lighting- designed to convert electrical energy into light.

By the method of installation, they are subdivided into:

Examples of

As an example of operating electrical installations, both specific equipment and their groups can be considered. In practice, the following devices should be distinguished as operating electrical installations:

• Electrical machines (motors, transformers, generators);
• Lines including wires, supports, brackets, insulators, cables and other equipment;
• Switches (air, oil vacuum and others), disconnectors and short-circuits;
• Rectifier and inverter plants for conversion;
• Devices for protection and overvoltage control, normalization of electricity parameters.

Residential consumers, in particular, wiring, switchboards, lighting devices and other devices can also be considered as an example of a working electrical installation.

Service

It should be noted that the operation of electrical installations must be carried out in accordance with the requirements of the rules. Therefore, only specially trained workers who have passed a knowledge test on electrical safety can be involved in the maintenance of electrical installations. They are obliged to carry out periodic inspection of equipment, maintenance, scheduled and extraordinary repairs, tests of electrical equipment and other manipulations. In this case, the electrical personnel serving electrical installations must fill out the relevant documents on the performance of certain types of work.

For constant monitoring of operating modes, in practice, operational maintenance of existing electrical installations is used. At the same time, work is carried out to perform switching operations, inspect devices, admit repair and operating personnel. Various operating modes are recorded, the compliance of power supply schemes is monitored.

Security measures

To ensure safe working conditions in existing electrical installations, a number of measures are envisaged. Which should be implemented at all stages - before the start, during and at the end of work. All activities are subdivided into organizational and technical. The first of them provide for the organization of certain actions in electrical installations (registration of work, appointment of persons in charge, preparation of the place of work, conduct of briefings, etc.). The latter provide for specific manipulations with electrical devices (switching switching, checking the presence or absence of voltage in live parts, installing protective earthing and others).

Depending on local conditions and the scope of application of existing electrical installations, safety measures can be supplemented in accordance with the characteristics of a particular industry.

Any sources and consumers of electricity must have a certain potential to counteract factors such as humidity, dust and temperature changes. helps to anticipate the possibility of touching individual parts of the equipment or getting inside of foreign particles. Another nuance requires special attention - the danger of electric shock to a person.

All organizational measures aimed at must be carried out taking into account the classification of equipment according to the following parameters:

• IP - designation of the degree of protection against external influences;
• type of climatic performance;
• belonging to the class of protection against potential electric shock.

The main hazards of electric shock

Thorough analysis and research conducted allow us to draw conclusions about the main points that affect the threat of exposure to current:

1. The nominal voltage of the installation.
2. The magnitude of the fault current relative to earth.
3. The operating mode of neutral of a separate power supply.
4. Resistance indicators of the human body.
5. Parameters of current-carrying elements in terms of resistance to grounded structures and earth.
6. The magnitude of the soil resistivity in the current zone.

How the premises are divided according to the degree of danger

Spaces characterized by the presence of at least one of the conditions are unsafe. These conditions are:

• conductive dust or moisture;
• high temperature;
• floors with high electrical conductivity;
• the potential danger of the presence of metal cases of equipment and the likelihood of simultaneous contact by a person of metal structures and technological equipment.

Each of these factors, alone or in combination with others, makes the premises a space with increased danger.

The most negative conditions include:

• placement of devices in an organic or chemically active environment;
• high degree of dampness;
• simultaneous presence of several conditions of increased threat.

With an open option for the placement of electrical installations, the highest degree of probability of injury to people by electricity is determined.

Division of equipment into groups according to PUE

This list includes installations for networks of 220 kV and more, which are used in networks with a neutral of a transformer with a dead-type earthing. With a neutral of an efficiently grounded type, the parameters of the networks are in the range of 110-220 kV. The latter option is used to perform the functions of limiting the fault current with respect to earth.

Installations with the mode of resonant grounding of neutrals of network elements and neutral of an insulated design in networks from 3 to 35 kV. Grounding, via resistors or arc suppression reactors, is necessary to compensate for capacitive currents at the time of a ground fault.

This group, used in work with small capacitive currents and an isolated neutral, includes 110, 220, 380 and 660 V networks.

Similar parameters with the previous group in terms of settings, except for 660 V networks.

Classification of electrical equipment by degree of protection

This indicator is usually determined using the Ingress Protection Rating classification system. Belonging to the security class will help to understand the special IP XX code. In it, the abbreviation XX denotes the following parameters:

The first number is the degree of mechanical protection.

The indicator of moisture resistance will be the second digit.

Alphanumeric code of climatic version

This symbol indicates the operating conditions for individual geographic areas. The numbers indicate the location condition, and the letters define the climatic region.

Protection classes

This indicator will be the main parameter for determining the chosen method of ensuring safety during the operation of electrical equipment and its degree for measures to prevent the threat of electric shock.

Consider the main design differences in devices due to its belonging to a certain category.