How electrical installations are divided by voltage. What is a live electrical installation? How is an external heart massage performed?

The conditions for the use of electrical equipment are very diverse:

These conditions have a significant impact on the safety, reliability and efficiency of various equipment.

To ensure a high level of safety and reliability, electrical equipment used in electrical installations, in terms of design, must comply with certain conditions for its operation.

These circumstances should be taken into account when:

design of electrical installations;

implementation of organizational and technical measures;

installation work;

repair and operation of electrical equipment.

To fulfill uniform requirements for the installation of electrical installations and electrical rooms, to establish the scope of application of electrical equipment with certain design features, to ensure its reliable operation in appropriate conditions and operating modes, as well as to meet the requirements of safe work performance by regulatory documents, a certain classification.

Electrical installations (EI)- a set of machines, apparatus, power lines and auxiliary equipment (together with premises) intended for the production, conversion, transformation, transmission, distribution and conversion of electrical energy into other types of energy.

According to the conditions of protection against atmospheric influences:

open (outdoor) - not protected;

closed (internal) - located inside the premises.

• over 1000 V - higher requirements for the device, design, personnel qualifications, organizational and technical measures.

Electrical rooms- premises or part of them (fenced off), in which electrical equipment (EE) is located, accessible only to qualified service personnel (special training, safety, exams, qualifications).

Classified by EP(according to PUE):

By the nature of the environment (relative humidity):

According to the danger of electric shock to people, rooms are distinguished:

• with increased danger (dampness, conductive dust, conductive floors, high temperature, the possibility of simultaneous contact of a person to the enclosures of electrical equipment and to grounded structures, devices, mechanisms).

At least the presence of one of these factors.

especially hazardous (special dampness, chemically active or organic media, the simultaneous presence of two or more factors of increased danger);

without increased danger - the absence of factors of increased or special danger.

According to the degree of the possibility of the formation of explosive mixtures, the explosive zones of the EI are divided into classes.

Instead of premises - zones that can occupy the entire premises or part of it. These zones are determined by technologists with electricians during design or operation. PUE established the following classes of explosive zones:

B-I - zones emitted where gases or vapors of flammable liquids, which can form explosive mixtures with air under normal operating conditions;

B-Iа - the same, but in case of accidents or malfunctions;

B-Ib - the difference from B-Ia - the presence of combustible gases with a pungent odor, hydrogen gas, laboratories with a small amount of gases or flammable liquids;

B-Ig - space near outdoor installations and technological installations with combustible gases and flammable liquids.

The dimensions of the explosive zones are 0.520 m vertically and horizontally from the place of formation of explosive mixtures.

B-II - areas in rooms where the formation of explosive mixtures of air with combustible dust or fiber is possible under normal conditions;

B-IIa - the same thing, but in case of accidents and malfunctions.

Explosive rooms also include rooms that do not have explosive technologies and materials, but are separated from explosive walls.

By the degree of formation of flammable substances.

Fire-hazardous premises or outdoor installations - in which flammable substances are periodically or constantly circulated, used, stored or formed during normal technological processes.

According to the degree of danger, the premises are also subdivided into fire hazardous zones of the following classes:

P-I - zones in which flammable liquids circulate with a flash above 61C;

P-II - zones in the premises of which flammable dust or fibers are emitted with a flammable limit of more than 65 to the volume of air;

P-IIa - zones in rooms containing solid combustible substances;

P-III - outdoor areas containing flammable liquids with flash C above 61C or solid flammable substances.

Classification and characteristics of electrical installations. Classification of electrical receivers (EP). EP characteristic. Brief description of the load graphs.

The purpose of the lecture:

Consider the classification and characteristics of electrical installations,

· Consider the classification and characteristics of power consumers;

· Consider a brief description of the load graphs (individual EF, group EF).

2.1. Classification and characteristics of electrical installations

The power supply system is connected with the production process through electrical installations and receivers of electrical energy.

Electrical installation(ES) - a set of machines, apparatus, power lines, auxiliary equipment intended for the production, transformation, transmission, storage, distribution of electrical energy and its transformation into another type of energy.

According to the PUE, all power plants are subdivided into power plants up to and above 1 kV. EI can work with both isolated and grounded neutral. ES above 1 kV are subdivided into installations with low and high earth fault currents.

Enlarged, the main part of the ES can be divided into the following groups:

Power general industrial installations;

Conversion installations;

Electrothermal installations;

Electric welding installations;

Lighting installations.

Power general industrial power plants: compressor, ventilation, pumping, etc. Consumers of this group create uniform and symmetrical load in all three phases. Their power varies widely from units to hundreds of kW. The power factor is fairly stable within 0.8 ÷ 0.85. In terms of the reliability of power supply, they should be attributed to electrical consumers of the 1st category.

Converter EI are intended for converting three-phase alternating current into direct current, converting industrial frequency of 50 Hz into currents with a frequency different from 50 Hz. Consumers of this group create a load on the primary voltage side, symmetrical and uniform across all three phases. Their power varies widely from tens to thousands of kW. The power factor ranges from 0.6 to 0.8. Interruption of power supply of the EI is mainly associated with under-delivery of products. Therefore, they should be classified as category 2 consumers.

Electrothermal power plants - arc, induction and resistance furnaces.

Arc furnaces (steel-making, furnaces for melting non-ferrous metals, ore-thermal furnaces). The load, on the primary voltage side of the step-down transformer, is symmetrical and uniform. Their power varies widely from tens to hundreds of thousands of kW. The power factor ranges from 0.7 to 0.8. In terms of the reliability of power supply, they should be attributed to electrical consumers of the 1st category.

Induction melting and quenching furnaces (high frequency). Electrical receivers of this group represent a symmetrical three-phase load on the primary voltage side of power transformers. Their power varies widely from tens to hundreds of kW. The power factor ranges from 0.7 to 0.8. The interruption in the power supply of the power plant is mainly associated with undersupply of products. Therefore, in terms of the reliability of power supply, they should be attributed to power consumers of the 2nd category.

Resistance furnaces. These electric drives are performed as three-phase and single-phase. Three-phase resistance furnaces create a symmetrical phase load. Single-phase ovens - no symmetrical load. Their power ranges from units to tens of kW. The power factor can practically be taken to be unity. According to the reliability of power supply, they should be classified as consumers of the 2nd category.

Electric welding power plants work on both alternating and direct current.

AC electric welding machines can be three-phase and single-phase. The operating mode is intermittent. DC electric welding installations consist of a converter unit, as a rule, three-phase. The load in the AC mains is distributed evenly across the three phases, but maintains an uneven load profile. The power factor of electric welding installations (for manual welding) ranges from 0.3 to 0.5. According to the reliability of power supply, they should be classified as electrical receivers of the 3rd category.

Electric lighting installations represent a single phase load. Due to the low power of the electrical receiver and with the correct distribution of the load over the phases, the load can be considered symmetrical. The load is uniform. The power factor depends on the type of light source. In those industries where the shutdown of lighting threatens the safety of people, special emergency lighting systems are used.

2.2. Classification of receivers of electrical energy

Receiver of electrical energy (EP) - an electrical device designed to convert electrical energy into another type of energy (or electrical energy, but with different parameters).

The specificity of technological processes of various industries imposes certain requirements on the characteristics and design of electrical receivers and, as a consequence, their great variety.

All EPs are classified according to various indicators:

By electrical performance;

By mode of operation;

Power supply reliability;

On the execution of protection against environmental influences.

Let us consider in more detail the classification of electrical receivers according to their indicators.

Electrotechnical indicators

Of all the variety, electrical receivers of power general industrial electrical installations can be divided into:

Electric drive of three-phase current with voltage above 1 kV, frequency 50 Hz;

Electric drive of three-phase current with voltage up to 1 kV, frequency 50 Hz;

EP single-phase current with voltage up to 1 kV, frequency 50 Hz;

Electric drives operating at a frequency other than 50 Hz;

DC electric drive.

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, 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%.

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

Especially damp, in which the relative humidity 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, devices, 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

Premises 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 most of the 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 / 220V network and are connected through an RCD (residual current device) to exclude the danger of electric shock to a person in the event of a voltage on the transformer case or when the high voltage passes to the winding 42 or 12V, 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 staircases 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, 220V voltage is used for tools and lamps.

Electrical installations is 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.

By stress distinguish between electrical installations:

- up to 1000 V ;

- over 1000 V .

By location electrical installations are:

- open or outdoor (installations protected by nets or canopies are considered outdoor);

- closed or internal.

With regard to the risk of injury to people and animals by electric current, rooms with electrical installations are divided into the following categories:

Premises with increased danger characterized by the presence in them of one of the following conditions that create an increased danger:

a) dampness or conductive dust;

b) conductive floors;

c) high temperature;

d) the possibility of simultaneous contact 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 cases of electrical equipment, on the other.

- especially dangerous premises characterized by the presence of one of the following conditions:

a) special dampness;

b) chemically active environment;

c) the simultaneous presence of two or more conditions of increased danger.

- premises without increased danger in which there are no conditions that create an increased and special danger.

According to environmental conditions, the premises in which the electrical installations are located are divided into the following categories:

- dry premises (relative humidity does not exceed 60%). These are heated premises for service personnel, hostels, heated warehouses, utility rooms in mechanical repair shops, etc.;

- dusty premises (according to production conditions, dust is emitted in them in such an amount that it can settle on wires, penetrate into machines, apparatus, etc.) - premises for crushing dry concentrated feed, feed mills, cement and other bulk non-combustible materials. ;

- wet premises (vapors or condensed moisture are released only temporarily, in small quantities, relative humidity is more than 60%, but does not exceed 75%) - dining rooms, stairwells, kitchens of living quarters, unheated warehouses, etc.;

- raw premises (relative humidity for a long time exceeds 75%) - vegetable stores, milking parlors, dairy, public canteen kitchens, etc., as well as, in the presence of microclimate installations, cowsheds, calf houses, pigsties, poultry houses and other livestock buildings .;

- especially raw premises (relative humidity close to 100%, ceiling, walls, floor and objects in the room are covered with moisture) - washing in workshops, feed shops for preparing wet feed, greenhouses, hotbeds, as well as outdoor installations under sheds .;

- especially damp rooms with a chemically active environment (at a relative air humidity close to 100%, the room constantly or for a long time contains vapors of ammonia, hydrogen sulfide and other gases of non-explosive concentration, or deposits are formed that act corrosively on the insulation and live parts of electrical equipment). These are warehouses of mineral fertilizers, livestock buildings in the absence of installations for creating a microclimate in them.

- fire hazardous premises of class P1, for example, warehouses for mineral oils. The same, class P II, for example woodworking shops, granaries. The same, class P IIa - warehouses for storing combustible materials, livestock buildings when storing hay and straw in attics.

- explosive premises - accumulator rooms, storage of oil products, etc.

Depending on the characteristics of the premises and electrical installations that are located in them, various requirements are imposed on the selection, execution and installation of machines, apparatus, devices, as well as to the selection and laying of electrical wires and cables, the fulfillment of which ensures the reliability and safety of maintenance of electrical installations.

According to the flammability of building materials, structures of buildings and surfaces of premises are divided into the following groups:

1. Fireproof structures, under the influence of fire or high temperature, they do not ignite, do not smolder and do not char.

2. Hardly combustible structures under the influence of fire or high temperature hardly ignite, smolder or char, and continue to burn or smolder only in the presence of a fire source.

3. Combustible structures under the influence of high temperature ignite and continue to burn or smolder after removal of the source of fire.

According to the storage method, electrical equipment is divided into the following groups.

1. Electrical equipment that does not require protection from atmospheric precipitation must be stored in open areas and overpasses.

2. Electrical equipment requiring protection from direct exposure to atmospheric precipitation and insensitive to temperature fluctuations must be stored in semi-open warehouses under common or individual sheds.

3. Electrical equipment and electrical structures that require protection from atmospheric precipitation and dampness and are not sensitive to temperature fluctuations, as well as all small parts must be stored in closed non-insulated warehouses.

4. Devices and critical mechanisms that are sensitive to temperature fluctuations must be stored in closed insulated warehouses.

Electrical equipment (E) and electrical devices (EU) in relation to the protection of personnel from touching live and moving parts and from the ingress of foreign objects, liquids and dust into the equipment (GOST 18311-80 *) are divided into the following main types: moisture resistant, open, protected , waterproof, splash-proof, drip-proof, dust-proof, closed, sealed, explosion-proof.

GOST 14254-80 establishes the characteristics of the degrees of protection of personnel from contact with live or moving parts inside the enclosure, as well as the degrees of protection of equipment built into the enclosure from the ingress of solid foreign bodies and the designation of these characteristics.

Table 1.1 shows the classes of electrical products according to the method of human protection.

Table 1.1 Classes of electrical equipment used in electrical installations with voltages up to 1000 V

Class according to GOST 12.2.007.0 RMEK536	Design features, marking:	Purpose of protection	Conditions for use in an electrical installation
Class 0	There is working insulation and there are no elements for grounding	When indirectly touched	1. Application in non-conductive rooms. 2. Power supply from the secondary winding of the isolation transformer of only one electrical receiver
Class I	There is a working insulation and a grounding element. The protective clip has a sign or letters PE, or yellow-green stripes	Also	Connection of the grounding clamp to the protective conductor of the electrical installation
Class II	There is double or reinforced insulation and no earthing elements. Sign	Also	Regardless of the protective measures taken in the electrical installation
Class III	There are no internal and external electrical circuits with a voltage higher than 42 V. Sign	From direct and indirect touch	Powered by a safe isolation transformer

Characteristics of the degrees of protection of the shells of electrical equipment with voltage up to 1000 V from injury to personnel and from the influence of the external environment are shown in Table 1.2.

Table 1.2 Characteristics of degrees of protection of enclosures of electrical equipment with voltage up to 1000 V

Degree of protection	Characteristics of the degree of protection
	personnel from contact with live or moving parts and equipment from ingress of foreign solid bodies inside the shell	equipment from the penetration of water into the shell
0	No protection	No protection
1	Protection against accidental contact of a large area of ​​the human body surface with live or moving parts inside the shell. There is no protection against deliberate access to these parts. Protection against ingress of foreign solid bodies with a diameter of at least 52.5 mm	Protection against drops of condensed water. Drops of condensed water falling vertically on the enclosure should not have a harmful effect on the equipment inside the enclosure.
2	Protection against the possibility of contact of human fingers with live parts or inside the shell. Protection against ingress of foreign solid bodies with a diameter of at least 12.5 mm	Protection against water droplets. Water drops falling on the shell, inclined at an angle of not more than 15 ° to the vertical, should not have a harmful effect on electrical equipment in the shell
3	Protection against contact of a tool, wire or other similar objects, the thickness of which exceeds 2.5 mm, with live or moving parts inside the enclosure. Protection against ingress of foreign bodies with a diameter of at least 2.5 mm	Rain protection. Rain falling on the enclosure inclined at an angle of not more than 60 ° to the vertical shall not have a harmful effect on the equipment inside the enclosure.
4	Protection against contact of the tool, wire or other objects, the thickness of which exceeds 1 mm, with live parts inside the sheath. Protection against ingress of foreign bodies with a diameter of at least 1 mm	Splash proof. Splashes of water from any direction falling on the enclosure shall not adversely affect the equipment inside the enclosure.
5	Full protection of personnel from contact with live or moving parts inside the enclosure. Protection against dust deposits	Protection against water jets. Water projected through the nozzle onto the enclosure in any direction shall not adversely affect the enclosed equipment.
6	The same and complete protection of equipment from dust ingress	Protection against impacts typical of the ship's deck (including deck watertight equipment)
7	-	Protection against immersion in water. Water must not penetrate the enclosure under the pressure and for the time specified in the standards or equipment specifications.
8	-	Protection against indefinitely long immersion in water. Water must not penetrate the enclosure at the pressure specified in the standard or specification

The designations of the degrees of protection of the shells of the apparatus are given in table 1.3, for electrical machines - in table 1.4.

The symbol for the degree of protection contains the following information:

IP - the first letters of the English words International Protection, denoting protection according to international standards;

The first number indicates the degree of protection against contact and ingress of foreign bodies;

The second digit indicates.

Table 1.3 Symbols of the degrees of protection of the shells of electrical devices with voltage up to 1000 V

	Degree of protection against water ingress
	0	1	2	3	4	5	6	7	8
0	IР00
1	IP10	IP11	IP12
2	IР20	IP21	IP22	IP23
3	IР30	IP31	IP32	IР33	IР34
4	IР40	IР41	IР42	IР43	IР44
5	IР50	IP51			IР54	IР55	IР56
6	IР60					IР65	IP66	IР67	IР68

Table 1.4 Symbols of the degrees of protection of electrical machines with voltage up to 1000 V

Degree of protection against contact and ingress of foreign bodies	Degree of protection against water ingress
	0	1	2	3	4	5	6	7	8
0	IР00	IР01
1	IP10	IP11	IP12	IP13
2	IР20	IP21	IP22	IP23
4				IР43	IР44
5					IР54	IР55	IР56

Example: the shell of electrical equipment, which protects personnel from the possibility of contacting fingers with live or moving parts of electrical equipment, which protects the equipment from the ingress of solid bodies with a diameter of at least 12.5 mm and from rain falling on the shell at an angle of not more than 60 ° to the vertical, is designated IP23 ...

In GOST 18311-80 * for certain types of electrical equipment and electrical devices, the following corresponding degrees of protection are named according to GOST 14254-80:

Open - IР00;

Protected - with all degrees of protection, except IP00;

Waterproof - IР55, IР65, IР56, IР66;

Splash-proof - IP34, IP44, IP54;

Drip-proof - IP01, IP11, IP21, IP31, IP41, IP51, IP12, IP22, IP32, IP42, IP13, IP23, IPZZ, IP43;

Dustproof - IP50, IP51, IP54, IP55, IP65, IP66, IP67, IP68;

Sealed -IP60, IP65, IP66, IP67, IP68.

The cooling method of an electric machine is indicated by the IC (International Cooling) symbol and numbers.

Electric machines with IP54 and IP44 degrees of protection are produced with the IC0141 cooling method.

The first two digits (01) define that the outer surface of the machine is blown by a fan mounted on the machine shaft and cooling the machine with ambient air through its shell. The next two digits (41) refer to the inside of the machine and indicate that the air inside the machine is driven by the rotor itself or an optional internal fan, and heat inside the machine is transferred to the environment through the surface of the bed, which can be smooth or ribbed.

Cooling method IC0041 differs from the previous one by the absence of an external fan. With the IC0151 cooling method, heat exchange between the air inside and outside the machine takes place with the help of a built-in cooler. Cooling method IC01 is used by machines of IР23 design.

Objects erected to meet the material and cultural needs of society are called structures. On a geometric basis, they are all divided: into volumetric (buildings of all types and purposes), site (sports grounds, storage areas) and linear (roads, overhead power lines, outdoor pipelines).

Structures located above the planning mark of the territory are called aboveground (overpasses, overpasses, towers), below the planning mark - underground (basements, cable lines) and deep (wells, wells).

A significant part of the structures are buildings, which, as a rule, are characterized by the presence of premises necessary for human activities. According to their purpose, buildings are subdivided into residential, public, industrial, agricultural and warehouse buildings. Public buildings include children's institutions, educational, commercial, medical, cultural, sports facilities, etc.

SNiP also provides for the classification of buildings and structures depending on the number of floors: industrial buildings are subdivided into one-story and multi-story, civil - one-story, low (2 or 3 floors), multi-story (up to 10 floors) and high-rise (more than 10 floors).

By the nature of the material of the outer walls, stone buildings (made of natural or artificial stone), wooden and mixed ones are distinguished.

By the type of load-bearing frame, buildings are distinguished with load-bearing external and internal walls, frame and combined (for example, box-type with load-bearing external walls and an internal frame).

Any building or structure consists of structural elements that perform specific functions. The main ones are foundations, walls, supports, ceilings, roofs, partitions, stairs, windows, lights and doors.

Foundation - it is an underground structure that receives the loads from the building and transfers them to the base, i.e. soil. The plane with which the foundation rests on the ground is called the base, and the distance from the base to the ground is called the depth of the foundation.

Walls separate the premises from the external space (external) or from the adjacent premises (internal). They may be carriers , perceiving, in addition to their own weight, the load from the floors and the roof and transmitting it to the foundation; self-supporting , perceiving their own weight and wind load and transmitting this load to the foundation; non-bearing , resting on the frame and perceiving their own weight within one floor. A fire-resistant and usually blank wall is called firewall.

Supports pillars or columns are called that support the floors and roof (and sometimes walls) and transfer the loads from them to the foundation.

Overlappings structures that divide the building in height are called. They receive and transmit to the walls or supports the loads that fall on them and, in addition, provide the spatial rigidity of the building. Depending on the installation location, the ceilings can be basements, interfloor and attic.

Roof serves as the top fence of a building or structure, protecting it from external atmospheric influences. The waterproof roof cladding is called roof , and the space between the roof and the attic floor - attic . In modern construction, an attic floor is often combined with a roof, and then such a structure is called an attic roof, or a combined roof.

Partitions - these are internal walls that divide the floor into separate rooms. Just like walls, they can be load-bearing or non-load-bearing, depending on the nature of the perceived load.

Stairs serve for communication between floors and, as a rule, are located in rooms enclosed by walls - staircases.

Window are intended for natural lighting of premises and their ventilation. If there are not enough windows to illuminate and ventilate a room (an art gallery or a workshop with a dusty production), they arrange lanterns - large openings with glazed movable frames.

Doors serve for communication between rooms (indoor) or between rooms and outdoor space (outdoor). In industrial, warehouse and other buildings for the delivery of equipment and materials are intended Gates .

The structure of the building may also include other elements - a porch, a balcony, etc.

When designing buildings and structures, artificial lighting and various sanitary devices are provided to provide heating, ventilation, air conditioning, gas supply, hot and cold water supply, sewerage, etc.).

Lecture 2

General questions of installation of electrical equipment

1. Classification of electrical installations and electrical rooms;

2. Classification of electrical equipment;

3. General information about materials and products used during installation;

4. Construction materials;

5. Electrical insulating materials;

6. Information about wiring products;

7. Tools and special equipment for installation;

Electrical installation accessories

Specialized machines and mobile workshops

Classification of electrical installations and electrical rooms

Electrical Installation Rules (PUE), chapter 1.1., Introduces the following terms and definitions:

Electrical installation it is a set of machines, apparatus, lines and auxiliary equipment (together with the structures and premises in which they are installed) intended for the production, transformation, transformation, transmission, distribution of electrical energy and its transformation into other types of energy.

According to the terms of electrical safety electrical installations are separated by operating voltage level for installations with voltages up to 1 kV and installations with voltages over 1 kV.

By location electrical installations can be open (or external) and closed (or internal). In the first case, electrical installations are not protected from atmospheric influences, in the second, they are protected. Installations protected by nets or canopies are classified as open.

Closed or internal electrical installations these are electrical installations located inside the building, protecting them from atmospheric influences.

Electrical rooms- rooms or fenced off (for example, nets) parts of the room in which electrical equipment is located, accessible only to qualified service personnel. They are classified as dry, wet, damp, especially wet, hot, dusty, chemically active or organic, normal.

Dry rooms- rooms in which the relative humidity does not exceed 60%.

Wet rooms- rooms in which the relative humidity is more than 60%, but does not exceed 75%.

Damp rooms- rooms in which the relative humidity exceeds 75%.

Particularly damp rooms- rooms in which the relative humidity is close to 100% (the ceiling, walls, floor and objects in the room are covered with moisture).

Heated rooms- rooms in which, under the influence of various thermal radiation, the temperature constantly or periodically (more than 1 day) exceeds +35 ° С (for example, rooms with dryers, kilns, boiler rooms).

Dusty rooms- premises in which, according to production conditions, technological dust is emitted, which can settle on live parts, penetrate into machines, apparatus, etc.

Dusty rooms are divided into rooms with conductive dust and rooms with non-conductive dust.

Rooms with a chemically active or organic environment- these are rooms in which aggressive vapors, gases, liquids are constantly or for a long time, deposits or mold are formed, destroying the insulation and live parts of electrical equipment

In the absence of the above conditions in such premises, they are called normal.

With regard to hazard defeat people with electric current, rooms with electrical installations are divided into three groups:

1) premises without increased danger in which there are no conditions that create an increased or special danger;

2) premises with increased danger characterized by the presence of one of the following conditions that create an increased hazard: dampness or conductive dust; conductive floors (metal, earth, reinforced concrete, brick, etc.); heat; the possibility of simultaneous contact of a person to the metal structures of buildings that have a connection to the ground, technological devices, mechanisms, etc., on the one hand, and to the metal cases of electrical equipment (open conductive parts), on the other;

3) especially dangerous premises characterized by the presence of one of the following conditions that create a particular hazard: special dampness; chemically active or organic medium; simultaneously two or more conditions of increased danger;

Territories, on which outdoor electrical installations are located, belong to especially dangerous premises.

Rooms for the installation and operation of electrical and electromechanical equipment must meet the following requirements. The distance between the elements of the building and the electrical installations moved to the installation site must be at least 0.3 m vertically and at least 0.5 m horizontally. The width of the passages between electrical installations and building elements is at least 1 m.For equipment with a voltage of up to 1 kV, the width of the passage between machines and control panels must be at least 2 m, and with the switchboard doors open - at least 0.6 m.

In rooms with electrical installations, areas for repair and installation of equipment, as well as the necessary lifting mechanisms, must be provided. Electrical and electromechanical equipment must be installed so that noise and vibration during operation does not exceed the permissible limits.

Similar information.