Unified system for design documentation.

GOST 2.709-89

Group T52

INTERSTATE STANDARD

Unified system for design documentation

DEFINITIONAL DESIGNATIONS OF WIRES AND CONTACT CONNECTIONS OF ELECTRICAL ELEMENTS, EQUIPMENT AND CIRCUITS IN ELECTRICAL CIRCUITS

Unified system of design documentation. Conventions of wires and terminal connections of electrical elements, equipment and subcircuits in circuit diagrams

ISS 01.080.40
31.180
OKSTU 0002

Date of introduction 1990-01-01

INFORMATION DATA

1. DEVELOPED AND INTRODUCED by the USSR State Committee for Standards

DEVELOPERS

S. S. Borushek; V.V. Gugnin; B.Ya. Kabakov; B. S. Mendrikov; S.L. Taller; N.K. Tokareva; P. A. Shalaev, Cand. tech. sciences

2. APPROVED AND PUT INTO EFFECT by the Decree of the USSR State Committee for Standards dated 03.24.89 N 669

3. The standard fully complies with ST SEV 3754-72, ST SEV 6308-88

4. REPLACE GOST 2.709-72

5. REFERENCE REGULATORY AND TECHNICAL DOCUMENTS


	Item number

6. REPUBLICATION. 2007 November

This standard applies to electrical circuits products of all industries and construction and establishes symbols for wires and clamps of electrical elements, devices, equipment, basic electrical elements (resistors, fuses, relays, transformers, rotating machines), motor control devices, power supply, grounding, connections to the body, circuit sections in electrical circuits.

1. GENERAL PROVISIONS

1.1. This International Standard specifies the methods used to distinguish terminals, as well as general rules for their uniform designation.

Note. The term "terminal designation" is used to designate conductive sections of the circuit and electrical elements intended for connection.

1.2. A single designation method can be used when using computer technology and transmitting information by teletype.

1.3. The drawings in this International Standard are given as examples to clarify the text.

2. METHODS OF DESIGNATION

2.1. An important criterion for the selection of the designation of the clamps is their function and location.

Distinctive features of the designation method are:

1) the location of the clamps according to the selected system;

2) conditional color according to the chosen system;

3) conventional graphic designation according to GOST 2.721;

4) alphanumeric designation according to Section 4.

Note. These methods are equivalent from the point of view of their use.

It is allowed to use graphic symbols according to GOST 2.721 instead of alphanumeric (see tables 1 and 2).

2.2. The choice of designation method depends on the type of device, the location of the terminals, and the complexity of the device or wiring.

2.3. Alphanumeric symbols are used for complex devices and wiring and are convenient for transmission over teletypewriter.

3. USE OF SYMBOLS

3.1. To designate the terminals of electrical elements, a conventional color is used, the corresponding graphic or alphanumeric designation.

3.2. When marking the clamps with a conventional color, the relationship between the color and the equivalent graphic or alphanumeric designation must be shown in the accompanying documentation.

3.3. If the design of a certain element or device does not allow the designation of the clamp, then the accompanying documentation must show the relationship between the location of the clamp, equivalent graphic or alphanumeric designations, and mutual arrangement clamps.

4. UNIFIED SYSTEM OF LETTER-DIGITAL DESIGNATIONS OF WIRES AND TERMINALS

4.1. When constructing alphanumeric symbols, capital letters of the Latin alphabet and Arabic numerals are used.

The letters I and O are not recommended.

4.2. The full designation consists of groups, each group consists of letters and / or numbers.

It is allowed to omit one or several groups, if this does not lead to an error when connecting.

A period is used to separate groups of numbers or letters only. If there is no need to distinguish between subsequent groups, the period can be omitted. For example, the full designation 1U11 can be written as follows: 1.11, if there is no need to indicate the U group; if there is no need to distinguish between subsequent groups, the period can be omitted: 111.

4.3. It is allowed to use the "+" and "-" signs when transmitting by TTY.

Designation principles

4.4. The designation system adheres to the following principles.

The two end points of the elements are designated by sequential numbers (for example, 1 and 2 in Fig. 1).

Intermediate points of a simple element are preferably designated by subsequent numbers (3, 4, 5, etc.).

The numbering of intermediate points starts from the end point indicated by the lower number. For example, the intermediate points of an element with end clamps 1 and 2 are denoted by the numbers 3, 4, 5 in Fig. 2.

4.5. When several identical elements are connected into groups, the ends of these elements are designated in the following way:

1) before the numbers in clause 4.4, letters are placed (for example, U, V, W) in accordance with the phases of the three-phase system (Fig. 3a);

2) in front of the numbers according to clause 4.4, if there is no need or the possibility of distinguishing between phases, place the next number. For example, the ends of one element are designated 1.1 and 1.2, and the same ends of the next element are 2.1 and 2.2, if this does not lead to the substitution of designations 11, 12 and 21, 22 (Fig. 3b).

4.6. Identical groups of elements, the ends of which within these groups are assigned designations in accordance with clause 4.5, are distinguished by placing the ordinal numbers of the groups in front of these designations according to Fig. 4.

The letter designation of the terminals for DC elements is preferably selected from the first half of the Latin alphabet, and for AC elements - from the second half of the alphabet.

Note. An example of the use of alphanumeric designations for wires and clamps of a three-phase system is shown in Fig. 5.

Terminal designations electrical devices connected to special wires are given in Table 1.

Table 1


Electrical device connection terminal	Designation
	alphanumeric	graphic
For alternating current:
1st phase
2nd phase
3rd phase
neutral wire
Protective wire
Ground wire
Silent ground wire
Body connection wire
Equipotential wire

Clamps of electrical devices intended for direct or indirect connection to the supply wires of a three-phase system are preferably designated with the letters U, V, W, if it is necessary to observe the phase sequence.

The clamp connected to the body is designated by the letters MM, the equipotential clamp - CC. This designation is used only when the connection of this terminal to the protective conductor or ground is not visible.

4.7. Special wire designations are given in Table 2.

table 2


Name	Designation
	alphanumeric	graphic
AC power system:
phase wire
1st phase
2nd phase
3rd phase
neutral wire
DC power system:
positive pole
negative pole
middle wire
Protective conductor with earth
Protective conductor, ungrounded
Connected protective and middle wire
Ground wire
Silent ground wire
Body connection wire
Equipotential wire

5. IDENTIFICATION OF CHAINS

5.1. The designation of the sections of the circuits serves for their identification, can reflect their functional purpose and create a connection between the circuit and the device.

5.2. When designating, capital letters of the Latin alphabet and Arabic numerals are used, made in the same font size.

5.3. The sections of the circuit, separated by the contacts of the devices, machine windings, resistors and other elements, must have a different designation.

5.4. Connections passing through non-separable, collapsible and detachable contact connections are denoted the same way. Different designations are allowed in justified cases.

5.5. The sections of the circuit in the diagram are designated regardless of the numbering of the input and output terminals of machines and devices.

5.6. The sequence of designation should be, as a rule, from the input (power source) to the consumer. Branching chains are indicated from top to bottom in a left-to-right direction.

For a convenient orientation in the diagrams, when designating sections of circuits, it is allowed to leave reserve numbers or skip some numbers.

5.7. The designation of an alternating current circuit consists of the designation of the sections of the phase circuits and a sequential number.


For example, sections of the chain	1st phase - L1, L11, L12, L13, etc.
	2nd phase - L2, L21, L22, L23, etc.
	3rd phase - L3, L31, L32, L33, etc.

An example of designation is shown in Fig. 6. Abbreviation of the designation according to clause 4.2 is allowed.

It is allowed, if this does not cause an erroneous connection, to designate the phases with the letters A, B, C, respectively.

5.8. To distinguish the phase or polarity wires belonging to different consumers, sequential numbers are used, which are placed in front of the designation of this phase or polarity (for example, the designation 2L1 means the wire of the first phase leading to the second consumer).

5.9. It is allowed to designate sections of the chain with sequential numbers, as indicated in Fig. 7.

5.10. DC circuits are denoted with odd numbers in positive polarity areas and even numbers in negative polarity areas. The input and output sections of the circuit are designated with polarity indication "L +" and "L-"; only the signs "+" and "-" are allowed (Fig. 8).

5.11. It is allowed to include the designation of phases in the designation of control, protection, signaling, automation, measurement circuits (Fig. 9).

In single-phase and two-phase non-power AC circuits, it is allowed to designate sections of the circuits with even and odd numbers.

It is allowed to include in the circuit designation a designation characterizing the functional purpose of the circuit. In this case, the sequence of numbers can be set within the functional circuit.

5.13. In the diagram, the designation is placed near the ends or in the middle of the chain section: to the left of the chain image - when the chain is vertical; above the chain image - when the chain is placed horizontally.

In technically justified cases, it is allowed to affix designations above the chain image.

5.14. The addresses of the connections of the circuit section can be used as a designation. In this case, at the beginning of the section, indicate the address of joining the end of the section, and at the end - the address of joining the beginning of the section. Alphanumeric designations of an element, device or functional group in accordance with GOST 2.710 (Fig. 10 and 11) are used as addresses.

It is allowed to use a mixed designation, consisting of an indication of the circuit and connection addresses (Fig. 12).

Electronic text of the document
prepared by Kodeks CJSC and verified by:
official publication
Unified design system
documentation: Sat. GOSTs. -
M .: Standartinform, 2008

STATE STANDARD OF THE UNION OF SSR

ONE WITHDESIGN DOCUMENTATION SYSTEM

OBOZSTARTING CONDITIONAL WIRES
AND CONTACT CONNECTIONS
ELECTRICAL ELEMENTS,
EQUIPMENT AND CIRCUITS
IN ELECTRICAL DIAGRAMS

GOST 2.709-89

(ST SEV 3754-82, ST SEV 6308-88)

STATETHE USSR STANDARDS COMMITTEE

Moscow

STATENEW STANDARD OF THE UNION SSR

Unified system for design documentation

DESIGNATIONS CONDITIONAL WIRES AND
ELECTRICAL CONTACT CONNECTIONS
ELEMENTS, EQUIPMENT AND AREAS
CIRCUITS IN ELECTRICAL CIRCUITS

Unified system of design documentation.
Conventions of wires and terminal connections of
electrical elements, equipment and subcircuits
in circuit diagrams

GOST
2.709-89

(CTWITHEV 3754-82,

CTCMEA6308-88)

Date of introduction01.01.90

This standard applies to electrical diagrams of products of all industries and construction and establishes the symbols for wires and terminals of electrical elements, devices, equipment, basic electrical elements (resistors, fuses, relays, transformers, rotating machines), motor control devices, power supply, grounding, connections to the body, sections of circuits in electrical circuits.

1. GENERAL PROVISIONS

1.1. This International Standard specifies the methods used to distinguish terminals, as well as general rules for their uniform designation.

Note. The term "terminal designation" is used to designate conductive sections of the circuit and electrical elements intended for connection.

1.2. A single designation method can be used when using computer technology and transmitting information by teletype.

1.3. The drawings in this International Standard are given as examples to clarify the text.

2. METHODS OF DESIGNATION

Distinctive features of the designation method are:

1) the location of the clamps according to the selected system;

2) conditional color according to the chosen system;

3) conventional graphic designation according to GOST 2.721;

4) alphanumeric designation according to sect. ...

Note. These methods are equivalent from the point of view of their use.

It is allowed to use graphic symbols according to GOST 2.721 instead of alphanumeric ones (see table and).

2.2. The choice of designation method depends on the type of device, the location of the terminals, and the complexity of the device or wiring.

2.3. Alphanumeric symbols are used for complex devices and wiring and are convenient for transmission over teletypewriter.

3. USE OF SYMBOLS

3.1. To designate the terminals of electrical elements, a conventional color is used, the corresponding graphic or alphanumeric designation.

3.2. When marking the clamps with a conventional color, the relationship between the color and the equivalent graphic or alphanumeric designation must be shown in the accompanying documentation.

3.3. If the design of a certain element or device does not allow designation of a clamp, then the accompanying documentation must show the relationship between the location of the clamp, equivalent graphic or alphanumeric designations, as well as the relative position of the clamps.

4. UNIFIED SYSTEM OF LETTER-DIGITAL DESIGNATIONS OF WIRES AND TERMINALS

4.1. When constructing alphanumeric symbols, capital letters of the Latin alphabet and Arabic numerals are used.

It is allowed to omit one or several groups, if this does not lead to an error when connecting.

A period is used to separate groups of numbers or letters only. If there is no need to distinguish between subsequent groups, the period can be omitted. For example, the full designation 1U11 can be written as follows: 1.11, if there is no need to indicate the U group; if there is no need to distinguish between subsequent groups, the period can be omitted: 111.

4.3. It is allowed to use the signs "+" and "-" when transmitting by teletype.

Designation principles

The two end points of the elements are designated by sequential numbers (for example, 1 and 2 in the drawing).

Intermediate points of a simple element are preferably designated by subsequent numbers (3, 4, 5, etc.).

The numbering of intermediate points starts from the end point indicated by the lower number. For example, the intermediate points of an element with end clamps 1 and 2 are denoted by the numbers 3, 4, 5 in dash. ...

The letter designation of the terminals for DC elements is preferably selected from the first half of the Latin alphabet, and for AC elements - from the second half of the alphabet.

Note. An example of the use of alphanumeric designations for wires and clamps of a three-phase system is shown in fig. ...

Designations of clamps of electrical devices connected to special wires are given in table. ...

Table 1

The clamp connected to the body is designated by the letters MM, the equipotential clamp - CC. This designation is used only when the connection of this terminal to the protective conductor or ground is not visible.

table 2

5. IDENTIFICATION OF CHAINS

5.1. The designation of the sections of the circuits serves for their identification, can reflect their functional purpose and create a connection between the circuit and the device.

5.2. When designating, capital letters of the Latin alphabet and Arabic numerals are used, made in the same font size.

5.3. The sections of the circuit, separated by the contacts of the devices, machine windings, resistors and other elements, must have a different designation.

5.4. Connections passing through non-separable, collapsible and detachable contact connections are denoted the same way. Different designations are allowed in justified cases.

5.5. The sections of the circuit in the diagram are designated regardless of the numbering of the input and output terminals of machines and devices.

5.6. The sequence of designation should be, as a rule, from the input (power source) to the consumer. Branching chains are indicated from top to bottom in a left-to-right direction.

For a convenient orientation in the diagrams, when designating sections of circuits, it is allowed to leave reserve numbers or skip some numbers.

5.7. The designation of an alternating current circuit consists of the designation of the sections of the phase circuits and a sequential number.

For example, the sections of the circuit of the 1st phase - L1, L11, L12, L13, etc.,

2nd phase - L2, L21, L22, L23, etc.,

3rd phase - L3, L31, L32, L33, etc.

An example of designation is shown in fig. ... Abbreviation of the designation according to p.

302kb.19.05.2009 17:57 177kb.19.05.2009 17:32 171kb.19.05.2009 17:30 45kb.19.05.2009 17:13

GOST 2.709-89.doc

GOST 2.709-89

Unified system for design documentation

DEFINITIONAL DESIGNATIONS OF WIRES AND CONTACT CONNECTIONS OF ELECTRICAL ELEMENTS, EQUIPMENT AND CIRCUITS IN ELECTRICAL CIRCUITS

Unified system of design documentation.

Conventions of wires and terminal connections of electrical elements, equipment and subcircuits in circuit diagrams

ST SEV 3754-82, ST SEV 6308-88

OKSTU 0002

01.01.90

This standard applies to electrical diagrams of products of all industries and construction and establishes the symbols for wires and clamps of electrical elements, devices, equipment, basic electrical elements (resistors, fuses, relays, transformers, rotating machines), motor control devices, power supply, grounding, connections to the body, sections of circuits in electrical circuits.

^ 1. GENERAL PROVISIONS

1.1. This International Standard specifies the methods used to distinguish terminals as well as to identify them uniformly.

Note. The term "terminal designation" is used to designate conductive sections of the circuit and electrical elements intended for connection.

^ 1.2. A single designation method can be used when using computer technology and transmitting information by teletype.

1.3. The drawings in this International Standard are given as examples to clarify the text.

^ 2. METHOD OF DESIGNATION

2.1. An important criterion for choosing a method of designating clamps is their function.

and location.

Distinctive features of the designation method are:

1) the location of the clamps according to the selected system;

2) a conditional center according to the chosen system;

^ 3) conventional graphic designation according to GOST 2.721;

4) alphanumeric designation according to sect. 4.

Note. These methods are equivalent from the point of view of their use.

It is allowed to use graphic symbols according to GOST 2.721 instead of alphanumeric ones (see tables 1 and 2).

^ 2.2. The choice of designation method depends on the type of device, the location of the terminals, and the complexity of the device or wiring.

2.3. Alphanumeric symbols are used for complex devices and wiring and are convenient for transmission over teletypewriter.

3. USE OF SYMBOLS

^ 3.1. To indicate the terminals of electrical elements, a conditional color is used, the corresponding graphic or alphanumeric designation.

3.2. When marking the clamps with a conventional color, the relationship between the color and the equivalent graphic or alphanumeric designation must be shown in the accompanying documentation.

^ 4. UNIFIED SYSTEM OF LETTER-DIGITAL DESIGNATIONS OF WIRES AND TERMINALS

4.1. When constructing alphanumeric symbols, capital letters of the Latin alphabet and Arabic numerals are used.

^ 4.2. The full designation consists of groups, each group consists of letters and / or numbers.

It is allowed to omit one or several groups, if this does not lead to an error when connecting.

^ 4.3. It is allowed to use the "+" and "-" signs when transmitting by TTY.

Principles of designation.

4.4. The designation system adheres to the following principles.

The two end points of the elements are designated by sequential numbers (for example, 1 and 2 in Fig. 1).

^ Intermediate points of a simple element are preferably designated by subsequent numbers (3, 4, 5, etc.).

Heck. 1

Damn 2

^ 4.5. When several identical elements are connected into groups, the ends of these elements are designated in the following way:

1) in front of the numbers in clause 4.4, letters are placed (for example U, V, W) in accordance with the phases of the three-phase system (Fig. 3a);

2) in front of the numbers in clause 4.4, if there is no need or the possibility of phase differentiation, place the next number. For example, the ends of one element are designated 1.1 and 1.2, and the same ends of the next element are 2.1 and 2.2, if this does not lead to the substitution of designations 11, 12 and 21, 22 (Fig. 36).

Damn. 3

Heck. 4

The letter designation of the terminals for DC elements is preferably selected from the first half of the Latin alphabet, and for AC elements - from the second half of the alphabet.

Note. An example of the use of alphanumeric designations for wires and clamps of a three-phase system is shown in fig. 5.

^ Damn. 5

Designations of clamps of electrical devices connected to special wires are given in table. 1.

Table 1

Electrical device connection terminal	Designation
Electrical device connection terminal	alphanumeric	graphic
For alternating current:	.	.
1st phase	U	.
2nd phase	V	.
3rd phase	W	.
neutral wire	N	.
Protective wire	PE	According to GOST 2.721
Ground wire	E	"
Silent ground wire	THOSE	"
Body connection wire	MM	"
Equipotential wire	SS	"

^ 4.7. Designations of wires of a special type are given in table. 2.

table 2

Name	Designation
Name	alphanumeric	graphic
AC power system:	.	.
phase wire	L	.
1st phase	L1	.
2nd phase	L2	.
3rd phase	L3	.
neutral wire	N	.
DC power system:	.	.
positive pole	L +	+
negative pole	L-	-
middle wire	M	.
Protective conductor with earth	PE	According to GOST 2.721
Protective conductor, ungrounded	PU	"
Connected protective and middle wire	PEN	"
Ground wire	E	"
Silent ground wire	THOSE	"
Body connection wire	MM	"
Equipotential wire	SS	"

5. IDENTIFICATION OF CHAINS

^ 5.1. The designation of the sections of the circuits serves for their identification, can reflect their functional purpose and create a connection between the circuit and the device.

5.2. When designating, capital letters of the Latin alphabet and Arabic numerals are used, made in the same font size.

^ 5.3. The sections of the circuit, separated by the contacts of the devices, machine windings, resistors and other elements, must have a different designation.

5.4. Connections passing through non-separable, collapsible and detachable contact connections are denoted the same way. Different designations are allowed in justified cases.

^ 5.5. The sections of the circuit in the diagram are designated regardless of the numbering of the input and output terminals of machines and devices.

5.6. The sequence of designation should be, as a rule, from the input (power source) to the consumer. Branching chains are indicated from top to bottom in a left-to-right direction.

For a convenient orientation in the diagrams, when designating sections of circuits, it is allowed to leave reserve numbers or skip some numbers.

^ 5.7. The designation of an alternating current circuit consists of the designation of the sections of the phase circuits and a sequential number.

For example, the sections of the circuit of the 1st phase are L1, L11, L12, L13, etc.

2nd phase - L2, L21, L22, L23, etc.

3rd phase - L3, L31, L32, L33, etc.

An example of designation is shown in fig. 6. Abbreviation of the designation according to clause 4.2 is allowed.

It is allowed, if this does not cause an erroneous connection, to designate the phases with the letters A, B, C, respectively.

Heck. 6

^ 5.9. It is allowed to designate sections of the chain with sequential numbers, as indicated in fig. 7.

Damn 7

Heck. eight

^ 5.11. It is allowed to include the designation of phases in the designation of control, protection, signaling, automation, measurement circuits (Fig. 9).

In single-phase and two-phase non-power AC circuits, it is allowed to designate sections of the circuits with even and odd numbers.

It is allowed to include in the circuit designation a designation characterizing the functional purpose of the circuit. In this case, the sequence of numbers can be set within the functional circuit.

Heck. nine

In technically justified cases, it is allowed to affix designations above the chain image.

STATE STANDARD

UNION SSR

UNIFIED SYSTEM OF DESIGN DOCUMENTATION

GOST 2.709 - 89

(ST SEV 3754 - 82, ST SEV 6308 - 88)

Official edition

USSR STATE COMMITTEE ON STANDARDS

UDC 621.332.35: 621.215.68: 006.354 Group T5J

STATE STANDARD OF THE UNION OF SSR

Unified system for design documentation

DEFINITIONAL DESIGNATIONS OF WIRES AND CONTACT CONNECTIONS OF ELECTRICAL ELEMENTS, EQUIPMENT AND CIRCUITS IN ELECTRICAL CIRCUITS

Unified system of design documentation. Conventions of wires and terminal connections of electrical elements, equipment and subcircuits in circuit diagrams

(CT SEV 3754-82, CT SEV 6308-88)

Date of introduction 01.01.90

1. GENERAL PROVISIONS

1.1. This International Standard specifies the methods used to distinguish terminals, as well as general rules for their uniform designation.

Note. The term "terminal designation" is used to designate conductive sections of the circuit and electrical elements intended for connection.

1.2. A single designation method can be used when using computer technology and transmitting information by teletype.

1.3. The drawings in this International Standard are given as examples to clarify the text.

Official edition ★

Reprinting prohibited © Standards Publishing House, 1989

2. METHODS OF DESIGNATION

2.1. An important criterion for the selection of the designation of the clamps is their function and location.

Distinctive features of the designation method are

1) the location of the clamps according to the selected system;

2) conditional color according to the chosen system;

3) conventional graphic designation according to GOST 2.721;

4) alphanumeric designation according to sect. 4.

Note. These methods are equivalent from the point of view of their used **.

It is allowed to use graphic designations according to FOCT 2.721 instead of alphanumeric ones (see tables 1 and 2).

2.2. The choice of designation method depends on the type of device, the location of the terminals, and the complexity of the device or wiring.

2.3. Alphanumeric symbols are used for complex devices and wiring and are convenient for transmission over teletypewriter.

3. USE OF SYMBOLS

3.1. To designate the terminals of electrical elements, a conventional color is used, the corresponding graphic or alphanumeric designation.

3.2. When marking the clamps with a conventional color, the relationship between the color and the equivalent graphic or alphanumeric designation must be shown in the accompanying documentation.

3.3. If the design of a certain element or devices "does not allow designating a clamp, then the accompanying documentation must show the relationship between the location of the clamp, equivalent graphic or alphanumeric designations, as well as the mutual arrangement of the clamps.

4. UNIFIED SYSTEM OF LETTER-DIGITAL DESIGNATIONS OF WIRES AND TERMINALS

4.1. When constructing alphanumeric symbols, capital letters of the Latin alphabet and Arabic numerals are used.

4.2. The full designation consists of groups, each group consists of letters and / or numbers.

It is allowed to omit one or several groups, if this does not lead to an error when connecting.

A period is used to separate groups consisting only of numbers or letters. If there is no need to distinguish between the following

groups, the dot can be omitted. For example, the full designation 1U11 can be written as follows: 1.11, if there is no need to indicate the U group; if there is no need to distinguish between subsequent groups, the period can be omitted: 111.

4.3. It is allowed to use the signs "+ e and" -> when transmitting by teletype.

Designation principles

4.4. The designation system adheres to the following principles.

The two end points of the elements are designated by consecutive

numbers (for example, 1 and 2 in Fig. 1).

Intermediate points of a simple element are preferably designated by subsequent numbers (3, 4, 5, etc.).

4.5. When several identical elements are connected into groups, the ends of these elements are designated in the following way:

1) letters (for example, U, V, W) are placed in front of the numbers in clause 4.4 in accordance with the phases of the three-phase system (Fig. 3a);

2) in front of the numbers according to clause 4.4, if there is no need for the possibility of distinguishing between phases, place the next number. For example, the ends of one element are designated 1.1 and 1.2, and the same ends of the next element are 2.1 and 2.2, if this does not lead to the substitution of designations II, 12 and 21, 22 (Fig. 36).

GTH "HP

LX

.xxJ

and and and

IL IVI / W) 2U1 2VI 7W

^ t: r "iY7l"? ll

IJ £ x.! 3L.J £ x.-u

w? 1V2 1 w? 2U2 in? W2 Damn * 4

The letter designation of the terminals for DC elements is preferably selected from the first half of the Latin alphabet, and for AC elements - from the second half of the alphabet.

Note. An example of the use of alphanumeric designations * of wires and clamps of a three-phase system is shown in fig. 5.

Designations of clamps of electrical devices connected to special wires are given in table. 1.

Table 1

4.7. Designations of wires of a special type are given in table. 2.

table 2

Continuation of table. I AM