Bsi bs en 60947 3 2009 + a2 2015

5.2.4 The following data shall be made available in the manufacturer's published information: a rated insulation voltage; b rated impulse withstand voltage for equipment suitable for is

Scope and object

This section of IEC 60947 pertains to switches, disconnectors, switch-disconnectors, and fuse-combination units designed for use in distribution and motor circuits, with a maximum rated voltage of 1,000 V a.c or 1,500 V d.c.

The manufacturer shall specify the type, ratings and characteristics according to the relevant standard of any incorporated fuses.

This section is not applicable to equipment covered by IEC 60947-2, IEC 60947-4-1, and IEC 60947-5-1 However, switches and fuse-combination units that fall under this section and are typically used to start, accelerate, or stop a single motor must adhere to the additional requirements outlined in Annex A.

The requirements for single pole operated three pole switches are included in Annex C

Auxiliary switches fitted to equipment within the scope of this part shall comply with the requirements of IEC 60947-5-1

This part does not include the additional requirements necessary for electrical apparatus for explosive gas atmospheres

NOTE 1 Depending on its design, a switch (or disconnector) can be referred to as "a rotary switch (disconnector)",

"cam-operated switch (disconnector)", "knife-switch (disconnector)", etc.

In this section, the term "switch" refers to devices known in French as "commutateurs," which are designed to alter connections between multiple circuits and, among other functions, to replace one part of a circuit with another.

NOTE 3 In general, throughout this part switches, disconnectors, switch-disconnectors and fuse-combination units will be referred to as "equipment".

The object of this part is to state a) the characteristics of the equipment; b) the conditions with which the equipment shall comply with reference to

1) operation and behaviour in normal service;

2) operation and behaviour in case of specified abnormal conditions, e.g short circuit;

3) dielectric properties; c) the tests for confirming that these conditions have been met and the methods to be adopted for these tests;

– 9 – d) the information to be marked on the equipment or made available by the manufacturer, e.g in the catalogue.

Normative references

The referenced documents are essential for applying this document For dated references, only the specified edition is applicable, while for undated references, the most recent edition, including any amendments, is relevant.

IEC 60050-441:1984, International Electrotechnical Vocabulary (IEV) ± Chapter 441: Switchgear, controlgear and fuses

IEC 60269 (all parts), Low-voltage fuses

IEC 60410:1973, Sampling plans and procedures for inspection by attributes

IEC 60417-DB:2000 1 ,Graphical symbols for use on equipment

IEC 60947-1:2007, Low-voltage switchgear and controlgear ± Part 1: General rules

IEC 60947-2:2006, Low-voltage switchgear and controlgear ± Part 2: Circuit-breakers

IEC 60947-4-1:2000, Low-voltage switchgear and controlgear ± Part 4-1: Contactors and motor-starters ± Electromechanical contactors and motor-starters

IEC 60947-5-1:2003, Low-voltage switchgear and controlgear ± Part 5-1: Control circuit devices and switching elements ± Electromechanical control circuit devices

IEC 61000-4-2:1995, Electromagnetic compatibility (EMC) ± Part 4-2: Testing and measurement techniques ± Electrostatic discharge immunity test

IEC 61000-4-3:2006, Electromagnetic compatibility (EMC) ± Part 4-3: Testing and measurement techniques ± Radiated, radio-frequency, electromagnetic field immunity test

IEC 61000-4-4:2004, Electromagnetic compatibility (EMC) ± Part 4-4: Testing and measurement techniques ± Electrical fast transient/burst immunity test

IEC 61000-4-5:2005, Electromagnetic compatibility (EMC) ± Part 4-5: Testing and measurement techniques ± Surge immunity test

IEC 61000-4-6:2003, Electromagnetic compatibility (EMC) ± Part 4-6: Testing and measurement techniques – Immunity to conducted disturbances, induced by radio-frequency fields

CISPR 11:2003, Industrial, scientific and medical (ISM) radio-frequency equipment ± Electromagnetic disturbance characteristics ± Limits and methods of measurement

1 “DB” refers to the IEC on-line database.

– 5 – d) the information to be marked on the equipment or made available by the manufacturer, e.g. in the catalogue

The referenced documents are essential for the application of this document For dated references, only the specified edition is applicable, while for undated references, the most recent edition, including any amendments, is relevant.

IEC 60417-DB:2000 1 , Graphical symbols for use on equipment

IEC 60947-2:2006,Low-voltage switchgear and controlgear ± Part 2: Circuit-breakers

– 5 – d) the information to be marked on the equipment or made available by the manufacturer, e.g in the catalogue

2 A consolidated edition 3.1 exists, including IEC 60947-1:2007 and its Amendment 1:2010.

This amendment has been prepared by subcommittee 121A: Low-voltage switchgear and controlgear, of IEC technical committee 121: Switchgear and controlgear and their assemblies for low voltage

The text of this amendment is based on the following documents:

Full information on the voting for the approval of this amendment can be found in the report on voting indicated in the above table

The committee has determined that the publication's content will stay the same until the stability date specified on the IEC website at "http://webstore.iec.ch" After this date, the publication will be updated accordingly.

• replaced by a revised edition, or

Replace the existing subclause by the following new subclause:

The referenced documents are essential for applying this document For dated references, only the specified edition is applicable, while for undated references, the most recent edition, including any amendments, is relevant.

IEC 60050-441:1984, International Electrotechnical Vocabulary (IEV) – Chapter 441

IEC 60947-1:2007, Low-voltage switchgear and controlgear – Part 1: General rules

1 “DB” refers to the IEC on-line database © IEC 2015

This amendment has been prepared by subcommittee 121A: Low-voltage switchgear and controlgear, of IEC technical committee 121: Switchgear and controlgear and their assemblies for low voltage

The text of this amendment is based on the following documents:

Full information on the voting for the approval of this amendment can be found in the report on voting indicated in the above table

The committee has determined that the publication's content will stay the same until the stability date specified on the IEC website at "http://webstore.iec.ch" for the relevant publication data After this date, the publication will be updated accordingly.

• replaced by a revised edition, or

Replace the existing subclause by the following new subclause:

IEC 60050-441:1984, International Electrotechnical Vocabulary (IEV) – Chapter 441

IEC 60947-1:2007, Low-voltage switchgear and controlgear – Part 1: General rules

1 “DB” refers to the IEC on-line database

IEC 60947-2:2006, Low-voltage switchgear and controlgear – Part 2: Circuit-breakers

IEC 60947-4-1:2009, Low-voltage switchgear and controlgear – Part 4-1: Contactors and motor-starters – Electromechanical contactors and motor-starters

IEC 60947-5-1:2003, Low-voltage switchgear and controlgear – Part 5-1: Control circuit devices and switching elements – Electromechanical control circuit devices

IEC 61000-4-2:2008, Electromagnetic compatibility (EMC) – Part 4-2: Testing and measurement techniques – Electrostatic discharge immunity test

IEC 61000-4-3:2006, Electromagnetic compatibility (EMC) – Part 4-3: Testing and measurement techniques – Radiated, radio-frequency, electromagnetic field immunity test

IEC 61000-4-4:2012, Electromagnetic compatibility (EMC) – Part 4-4: Testing and measurement techniques – Electrical fast transient/burst immunity test

IEC 61000-4-5:2014, Electromagnetic compatibility (EMC) – Part 4-5: Testing and measurement techniques – Surge immunity test

IEC 61000-4-6:2013, Electromagnetic compatibility (EMC) – Part 4-6: Testing and measurement techniques – Immunity to conducted disturbances, induced by radio-frequency fields

CISPR 11:2009, Industrial, scientific and medical equipment – Radio-frequency disturbance characteristics – Limits and methods of measurement

CISPR 22:2008, Information technology equipment – Radio disturbance characteristics –

Limits and methods of measurement

Replace the title and text of the existing clause, modified by Amendment 1, by the following new title and text:

2 Terms, definitions and index of terms

General

For the purposes of this document, the terms and definitions given in IEC 60050-441 and IEC 60947-1 as well as the following apply

 d) the information to be marked on the equipment or made available by the manufacturer, e.g in the catalogue

IEC 60050-441:1984, International Electrotechnical Vocabulary (IEV) ± Chapter 441:

IEC 60947-2:2006, Low-voltage switchgear and controlgear ± Part 2: Circuit-breakers

CISPR 11:2003, Industrial, scientific and medical (ISM) radio-frequency equipment ±

Electromagnetic disturbance characteristics ± Limits and methods of measurement

– 5 – d) the information to be marked on the equipment or made available by the manufacturer, e.g. in the catalogue

– 5 – d) the information to be marked on the equipment or made available by the manufacturer, e.g in the catalogue

2 A consolidated edition 3.1 exists, including IEC 60947-1:2007 and its Amendment 1:2010.

– 11 – © IEC 2015 IEC 60947-2:2006, Low-voltage switchgear and controlgear – Part 2: Circuit-breakers

IEC 60947-3:2008/AMD2:2015 – 3 – © IEC 2015 IEC 60947-2:2006, Low-voltage switchgear and controlgear – Part 2: Circuit-breakers

IEC 60947-2:2006, Low-voltage switchgear and controlgear – Part 2: Circuit-breakers

For the purposes of this document, the terms and definitions given in IEC 60050-441 and

IEC 60947-1 as well as the following apply

Alphabetical index of terms

Disconnector 2.3.1 Disconnector-fuse 2.3.5 Disconnector-fuse single opening 2.3.5.1 Disconnector-fuse double opening 2.3.5.2

The article discusses various types of electrical components, including the fuse-combination unit (2.3.2), fuse-disconnector (2.3.6), and its subcategories: single opening (2.3.6.1) and double opening (2.3.6.2) It also covers the fuse-switch (2.3.4), with single opening (2.3.4.1) and double opening (2.3.4.2) variants Additionally, the fuse-switch-disconnector (2.3.8) is examined, along with its single opening (2.3.8.1) and double opening (2.3.8.2) options.

The article discusses various electrical devices and their operational characteristics, including semi-independent manual operation (2.3.10) and single pole operated three pole devices (2.3.9) It details switch-disconnector-fuses, highlighting single opening (2.3.7.1) and double opening (2.3.7.2) configurations Additionally, it covers switch-fuses, specifying single opening (2.3.3.1) and double opening (2.3.3.2) options.

Terms and definitions

2.3.1 disconnector mechanical switching device which, in the open position, complies with the requirements specified for the isolating function

A disconnector is designed to open and close a circuit with negligible current or minimal voltage change across its terminals It can handle normal circuit currents and sustain specified currents during abnormal conditions, such as short-circuits, for a limited duration.

[SOURCE: IEC 60050-441:1984, 441-14-05, modified – reference to isolating function instead of isolating distance]

2.3.2 fuse-combination unit combination of a mechanical switching device and one or more fuses in a composite unit, assembled by the manufacturer or in accordance with his instructions

2.3.3 switch-fuse switch in which one or more poles have a fuse in series in a composite unit [SOURCE: IEC 60050-441:1984, 441-14-14]

Disconnector 2.3.1 Disconnector-fuse 2.3.5 Disconnector-fuse single opening 2.3.5.1 Disconnector-fuse double opening 2.3.5.2

The article discusses various types of electrical components, including the fuse-combination unit (2.3.2), fuse-disconnector (2.3.6), and its subcategories: single opening (2.3.6.1) and double opening (2.3.6.2) It also covers the fuse-switch (2.3.4) and its variations, such as single opening (2.3.4.1) and double opening (2.3.4.2) Additionally, the fuse-switch-disconnector (2.3.8) is examined, along with its single opening (2.3.8.1) and double opening (2.3.8.2) configurations.

The article discusses various electrical devices, including semi-independent manual operation (2.3.10) and single pole operated three pole devices (2.3.9) It also covers switch-disconnector-fuses, detailing single opening (2.3.7.1) and double opening (2.3.7.2) configurations Additionally, the article addresses switch-fuses, with specifications for single opening (2.3.3.1) and double opening (2.3.3.2) options.

2.3.1 disconnector mechanical switching device which, in the open position, complies with the requirements specified for the isolating function

A disconnector is designed to open and close a circuit with negligible current or minimal voltage change across its terminals It can handle normal circuit currents and sustain specified currents during abnormal conditions, such as short-circuits, for a limited duration.

[SOURCE: IEC 60050-441:1984, 441-14-05, modified – reference to isolating function instead of isolating distance]

2.3.2 fuse-combination unit combination of a mechanical switching device and one or more fuses in a composite unit, assembled by the manufacturer or in accordance with his instructions

2.3.3 switch-fuse switch in which one or more poles have a fuse in series in a composite unit

2.3.3.1 switch-fuse single opening switch-fuse which provides an interruption in the circuit on one side of the fuse-link only

Note 1 to entry: With this arrangement safety precautions may be necessary when removing fuse-links

2.3.3.2 switch-fuse double opening switch-fuse which provides an interruption in the circuit on both sides of the fuse-link

2.3.4 fuse-switch switch in which a fuse-link or fuse-carrier with fuse-link forms the moving contact

2.3.4.1 fuse-switch single opening fuse-switch which provides an interruption in the circuit on one side of the fuse-link only

Note 1 to entry: With this arrangement, safety precautions may be necessary when removing fuse-links

2.3.4.2 fuse-switch double opening fuse-switch which provides an interruption in the circuit on both sides of the fuse-link

NOTE 1 to entry: With this arrangement, safety precautions may be necessary when removing fuse-links

2.3.5 disconnector-fuse disconnector in which one or more poles have a fuse in series in a composite unit

A disconnector-fuse with a single opening offers a circuit interruption on at least one side of the fuse-link, fulfilling the specified requirements for isolating functionality.

2.3.5.2 disconnector-fuse double opening disconnector-fuse which provides an opening in the circuit that satisfies the requirements specified for the isolating function on both sides of the fuse-link

2.3.6 fuse-disconnector disconnector in which a fuse-link or fuse-carrier with fuse-link forms the moving contact

A fuse-disconnector with a single opening is designed to create a circuit interruption on at least one side of the fuse-link, ensuring compliance with the specified isolating function requirements.

Note 1 to entry: With this arrangement, safety precautions may be necessary when removing fuse-links.

2.3.4 fuse-switch switch in which a fuse-link or fuse-carrier with fuse-link forms the moving contact [SOURCE: IEC 60050-441:1984, 441-14-17]

2.3.5 disconnector-fuse disconnector in which one or more poles have a fuse in series in a composite unit [SOURCE: IEC 60050-441:1984, 441-14-15]

A disconnector-fuse with a single opening offers a circuit interruption on at least one side of the fuse-link, fulfilling the specified requirements for effective isolation.

2.3.6 fuse-disconnector disconnector in which a fuse-link or fuse-carrier with fuse-link forms the moving contact [SOURCE: IEC 60050-441:1984, 441-14-18]

2.3.4 fuse-switch switch in which a fuse-link or fuse-carrier with fuse-link forms the moving contact

2.3.5 disconnector-fuse disconnector in which one or more poles have a fuse in series in a composite unit

A disconnector-fuse with a single opening offers a circuit interruption on at least one side of the fuse-link, fulfilling the necessary criteria for effective isolation.

2.3.6 fuse-disconnector disconnector in which a fuse-link or fuse-carrier with fuse-link forms the moving contact

2.3.6.2 fuse-disconnector double opening fuse-disconnector which provides an opening in the circuit, that satisfies the requirements specified for the isolating function, on both sides of the fuse-link

2.3.7 switch-disconnector-fuse switch-disconnector in which one or more poles have a fuse in series in a composite unit [SOURCE: IEC 60050-441:1984, 441-14-16]

A switch-disconnector-fuse with a single opening offers circuit interruption on at least one side of the fuse-link, meeting the specified requirements for effective isolation.

The switch-disconnector-fuse features a double opening mechanism that ensures circuit interruption on both sides of the fuse-link, meeting the specified requirements for effective isolation.

2.3.8 fuse-switch-disconnector switch-disconnector in which a fuse-link or fuse-carrier with fuse-link forms the moving contact [SOURCE: IEC 60050-441:1984, 441-14-19]

The fuse-switch-disconnector features a single opening that ensures circuit interruption on at least one side of the fuse-link, meeting the specified requirements for effective isolation.

The double opening fuse-switch-disconnector ensures circuit interruption on both sides of the fuse-link, meeting the specified requirements for effective isolation.

A single pole operated three pole device is a mechanical unit that includes three independently operable single pole switches and/or disconnecting units This device is rated as a complete unit for application in a three-phase system.

Summary of the equipment types

A summary of equipment definitions and relevant diagrams is given in Table 1

2.3.7 switch-disconnector-fuse switch-disconnector in which one or more poles have a fuse in series in a composite unit

The switch-disconnector-fuse features a single opening that ensures circuit interruption on at least one side of the fuse-link, meeting the specified requirements for effective isolation.

The switch-disconnector-fuse features a double opening mechanism that ensures circuit interruption on both sides of the fuse-link, effectively meeting the specified requirements for isolating functions.

2.3.8 fuse-switch-disconnector switch-disconnector in which a fuse-link or fuse-carrier with fuse-link forms the moving contact [SOURCE: IEC 60050-441:1984, 441-14-19]

The fuse-switch-disconnector features a double opening mechanism that ensures circuit interruption on both sides of the fuse-link, effectively meeting the specified requirements for isolating functions.

These mechanical units are designed for power distribution systems that require the switching or isolation of individual phases They are not suitable for switching the primary circuit of three-phase equipment.

Semi-independent manual operation involves using direct manual energy to control a process The manual force applied can be increased until it reaches a threshold value, at which point independent switching occurs, unless the operator intentionally delays this action.

2.4 Summary of the equipment types

Table 1 – Summary of equipment definitions

Functions Making and breaking current Isolating Making, breaking and isolating

Switch-disconnector-fuse single opening a

Switch-fuse double opening b Disconnector-fuse double opening Switch-disconnector-fuse double opening b

Fuse-switch single opening a Fuse-disconnector single opening a Fuse-switch-disconnector single opening a

Fuse-switch double opening b Fuse-disconnector double opening Fuse-switch-disconnector double opening b

Equipment depicted with a single opening may actually consist of multiple openings arranged in series The fuse can be positioned on either side of the equipment's contacts Additionally, depending on the design, the breaking action may occur on one or both sides of the fuse-link.

Replace the existing text of this subclause including 4.2.1, 4.2.2, 4.2.3 and changes introduced in Amendment 1 by the following:

The following information shall be stated:

• in the case of a.c., number of phases and rated frequency;

• number of positions of the main contacts (if more than two);

• breaking arrangement for fused devices (single opening or double opening)

Replace the existing item 5.2.2.c) by the following: c) rated operational currents (or rated powers) with the corresponding rated operational voltage and utilization category (see 4.3.1, 4.3.2 and 4.4);

According to the utilization category

According to the method of operation of manually operated equipment

– dependent manual operation ( see 2.4.12 of IEC 60947-1 );

– independent manual operation ( see 2.4.15 of IEC 60947-1 );

– semi-independent manual operation ( see 2.3.10 )

NOTE The method of operation on closing may be different from the method for opening.

According to suitability for isolation

– suitable for isolation (see 7.1.7 of IEC 60947-1 and 7.1.7.1);

According to the degree of protection provided

Switch-disconnector-fuse single break b a

Switch-disconnector-fuse double break b

Fuse-switch-disconnector single break b

Fuse-switch-disconnector double break b

NOTE 1 Equipment shown as single break may be double break

The symbols used are derived from IEC 60617-7 It is important to note that the fuse can be positioned on either side of the equipment contacts or may be stationary between them Additionally, disconnection between the line and load terminals is confirmed through testing.

Type of equipment

3 Classification 3.1 According to the utilization category

3.2 According to the method of operation of manually operated equipment

3.3 According to suitability for isolation

3.4 According to the degree of protection provided

The characteristics of the equipment shall be stated in terms of the following as applicable:

– rated and limiting values for the main circuit (see 4.3);

Rated and limiting values for the main circuit

Rated values are assigned by the manufacturer They shall be stated in accordance with 4.3.1 to 4.3.6.4 but it may not be necessary to establish all the rated values listed

An equipment is defined by the following rated voltages

4.3.1.3 Rated impulse withstand voltage (U imp )

An equipment is defined by the following currents.

4.3.2.1 Conventional free air thermal current (I th )

4.3.2.2 Conventional enclosed thermal current (I the )

• breaking arrangement for fused devices (single break or double break)

4.3 Rated and limiting values for the main circuit

The switch-disconnector-fuse features a single opening that ensures circuit interruption on at least one side of the fuse-link, meeting the specified requirements for effective isolation.

2.3.8 fuse-switch-disconnector switch-disconnector in which a fuse-link or fuse-carrier with fuse-link forms the moving contact

These mechanical units are designed for power distribution systems that require the switching or isolation of individual phases However, they should not be utilized for switching the primary circuit of three-phase equipment.

Semi-independent manual operation involves the use of direct manual energy to perform tasks In this process, the manual force applied can be increased until it reaches a specific threshold Once this threshold is surpassed, an independent switching operation occurs, unless the operator intentionally delays it.

Equipment depicted with a single opening may actually consist of multiple openings arranged in series The fuse can be positioned on either side of the equipment's contacts Additionally, depending on the design, the breaking action may occur on one or both sides of the fuse-link.

• breaking arrangement for fused devices (single opening or double opening).

The characteristics of the equipment shall be stated in terms of the following as applicable: – type of equipment (see 4.2);

4.3.2.3 Rated operational currents (I e ) (or rated operational powers)

The rated duties considered as normal are as follows

4.3.5 Normal load and overload characteristics

4.3.5.1 Ability to withstand motor switching overload currents

Subclause 4.3.5.2 of IEC 60947-1 applies with the following additions

The rated making capacity is stated by reference to the rated operational voltage and rated operational current and to the utilization category according to Table 3

Not applicable to AC-20 or DC-20 equipment

The rated breaking capacity is stated by reference to the rated operational voltage and rated operational current and to the utilization category according to Table 3

4.3.6.1 Rated short-time withstand current (I cw )

The rated short-time withstand current of a switch, disconnector, or switch-disconnector is the maximum short-time withstand current specified by the manufacturer, which the equipment can safely carry without sustaining damage under the test conditions outlined in section 8.3.5.1.

The rated short-time withstand current must be at least twelve times the maximum rated operational current, with a duration of 1 second unless specified otherwise by the manufacturer.

4.3.5 Normal load and overload characteristics 4.3.5.1 Ability to withstand motor switching overload currents

4.3.6 Short-circuit characteristics 4.3.6.1 Rated short-time withstand current (I cw )

The rated short-time withstand current of a switch, disconnector, or switch-disconnector is the maximum short-time current that the manufacturer certifies the equipment can handle without sustaining damage, as specified under the test conditions outlined in section 8.3.5.1.

In alternating current (a.c.) systems, the current is represented by its root mean square (r.m.s.) value, which is considered the standard measure It is assumed that the maximum peak value of the a.c component will not exceed a specified multiple, denoted as \( n \), of this r.m.s value, with the factor \( n \) outlined in Table 16 of IEC 60947-1.

4.3.6.2 Rated short-circuit making capacity (I cm )

4.3.6.3 Vacant 4.3.6.4 Rated conditional short-circuit current

Utilization category

The utilization categories define the intended applications and are given in Table 2

Each utilization category is defined by the values of currents and voltages, represented as multiples of the rated operational current and voltage, along with the power factors or time constants of the circuit The conditions for making and breaking, outlined in Table 3, align with the applications specified in Table 2.

The designation of utilization categories is completed by the suffix A or B according to whether the intended applications require frequent or infrequent operations (see Table 4)

Utilization categories with the suffix B are suitable for devices designed for infrequent operation This includes disconnectors typically used for maintenance isolation and switching devices where the fuse-link blade acts as the moving contact.

The distinction between frequent and infrequent operation is based on the manufacturer’s rated operation and the number of operating cycles used as a test criterion in Table 4

A device is classified as suitable for frequent use (category A) if its manufacturer's rated operating life exceeds the number of operating cycles specified in columns 3, 4, or 5 of Table 4, given a specific rated operational current.

Subclause 4.3.6.2 of IEC 60947-1 applies with the following addition

NOTE I cm is not applicable to fused devices

– Connecting and disconnecting under no-load conditions

– Switching of resistive loads including moderate overloads

– Switching of mixed resistive and inductive loads, including moderate overloads – Switching of motor loads or other highly inductive loads

– Connecting and disconnecting under no- load conditions

– Switching of resistive loads including moderate overloads

– Switching of mixed resistive and inductive loads, including moderate overloads (e.g shunt motors)

– Switching of highly inductive loads (e.g series motors) a The use of these utilization categories is not permitted in the USA.

Category AC-23 includes occasional switching of individual motors The switching of capacitors or of tungsten filament lamps shall be subject to agreement between manufacturer and user

The utilization categories outlined in Tables 2 and 3 are not applicable to equipment typically used for starting, accelerating, or stopping individual motors Instead, the relevant utilization categories for this type of equipment are addressed in Annex A.

Control circuits

Auxiliary circuits

Relays and releases

Subclause 5.1 of IEC 60947-1 applies as appropriate for a particular design

Typical applications Nature of current

Co-ordination with short circuit protective devices (SCPD)

In alternating current (a.c.) systems, the current is represented by its root mean square (r.m.s.) value It is assumed that the maximum peak value will not exceed a specified multiple, denoted as n, of this r.m.s value, with the factor n provided in Table 16 of IEC 60947-1.

4.3.6.4 Rated conditional short-circuit current

Each utilization category is defined by the current and voltage values, represented as multiples of the rated operational current and voltage, along with the circuit's power factors or time constants The making and breaking conditions outlined in Table 3 align with the applications specified in Table 2.

Utilization categories with the suffix B are suitable for devices designed for infrequent operation This includes disconnectors typically used for maintenance isolation and switching devices where the fuse-link blade acts as the moving contact.

The distinction between frequent and infrequent operation is based on the manufacturer’s rated operation and the number of operating cycles used as a test criterion in Table 4

A device is classified as suitable for frequent use (category A) if its manufacturer's rated operating life exceeds the number of operating cycles specified in columns 3, 4, or 5 of Table 4, given a specific rated operational current.

Subclause 4.3.6.2 of IEC 60947-1 applies with the following addition

NOTE I cm is not applicable to fused devices

Marking

3 Classification 3.1 According to the utilization category

3.2 According to the method of operation of manually operated equipment

3.3 According to suitability for isolation

3.4 According to the degree of protection provided

The switch-disconnector-fuse features a single opening mechanism that ensures circuit interruption on at least one side of the fuse-link, meeting the specified requirements for effective isolation.

2.3.8 fuse-switch-disconnector switch-disconnector in which a fuse-link or fuse-carrier with fuse-link forms the moving contact

These mechanical units are designed for power distribution systems that require the switching or isolation of individual phases However, they should not be utilized for switching the primary circuit of three-phase equipment.

Semi-independent manual operation involves the use of direct manual energy to control a system In this process, the manual force is applied until it reaches a specific threshold, at which point an independent switching operation occurs, unless the operator intentionally delays it.

The equipment illustrated with a single opening may actually consist of several openings arranged in series The fuse can be positioned on either side of the equipment's contacts, and depending on the design, the breaking action may occur on one or both sides of the fuse-link.

• breaking arrangement for fused devices (single opening or double opening).

The characteristics of the equipment shall be stated in terms of the following as applicable: – type of equipment (see 4.2);

4.3.5 Normal load and overload characteristics

4.3.5.1 Ability to withstand motor switching overload currents

4.3.6.1 Rated short-time withstand current (I cw )

The rated short-time withstand current of a switch, disconnector, or switch-disconnector is the maximum short-time withstand current specified by the manufacturer, which the equipment can endure without sustaining damage under the testing conditions outlined in section 8.3.5.1.

4.3.5 Normal load and overload characteristics 4.3.5.1 Ability to withstand motor switching overload currents

4.3.6 Short-circuit characteristics 4.3.6.1 Rated short-time withstand current (I cw )

The rated short-time withstand current of a switch, disconnector, or switch-disconnector is the maximum short-time withstand current specified by the manufacturer, which the equipment can safely carry without sustaining damage under the test conditions outlined in section 8.3.5.1.

In alternating current (a.c.) systems, the current is represented by its root mean square (r.m.s.) value It is assumed that the maximum peak value will not exceed a factor of \( n \) times this r.m.s value, with the specific factor \( n \) provided in Table 16 of IEC 60947-1.

4.3.6.3 Vacant 4.3.6.4 Rated conditional short-circuit current

Each utilization category is defined by the values of currents and voltages, represented as multiples of the rated operational current and voltage, along with the power factors or time constants of the circuit The conditions for making and breaking, as outlined in Table 3, align with the applications specified in Table 2.

Tiêu đề	Low-voltage Switchgear And Controlgear Part 3: Switches, Disconnectors, Switch-disconnectors And Fuse-combination Units
Trường học	British Standards Institution
Chuyên ngành	Standards Publication
Thể loại	Standard
Năm xuất bản	2015
Thành phố	London

Định dạng
Số trang	72
Dung lượng	2,52 MB