GB/T 7251.3-2017 Low-voltage switchgear and controlgear assemblies-Part 3:Distribution boards intended to be operated by ordinary persons ( DBO) (English Version)
Codeofchina.com is in charge of this English translation. In case of any doubt about the English translation, the Chinese original shall be considered authoritative.
GB/T 7251 Low-voltage Switchgear and Controlgear Assemblies consists of the following parts:
——Part 1: General Rules
——Part 3: Distribution Boards Intended to be Operated by Ordinary Persons (DBO);
——Part 4: Particular Requirements for Assemblies for Construction sites (ACS);
——Part 5: Assemblies for Power Distribution in public Networks;
——Part 6: Busbar Trunking Systems (Busways);
——Part 7: Assemblies for Specific Applications such as Marinas, Camping Sites, Market Squares, Electric Vehicles Charging Stations.
——Part 8: General Technology Requirement for Intelligent Assemblies;
——Part 10: Guidance to Specifying Assemblies;
——Part 12: Power Switchgear and Controlgear Assemblies
This part is Part 3 of GB/T 7251.
This part is developed in accordance with the rules given in GB/T 1.1-2009.
This part replaces GB/T 7251.3-2006 Low-voltage Switchgear and Controlgear Assemblies - Part 3: Particular Requirements for Low-voltage Switchgear and Controlgear Assemblies Intended to Be Installed in Places Where Unskilled Persons Have Access for Their Use - Distribution Boards; the following technical changes have been made with respect to GB/T 7251.3-2006 (the previous edition):
——The relevant structure and technical contents are adjusted according to GB/T 7251.1-2013.
This part is used in conjunction with GB/T 7251.1-2013.The general rules of GB/T 7251.1-2013 are applicable to only the scope where they are cited. If chapter and clause, figure as well as Appendix of general rules are to be used, it shall be made clear by reference to GB/T 7251.1-2013, e.g. 1.2.3 of GB/T 7251.1-2013, Table 4 of GB/T 7251.1-2013 or Appendix A of GB/T 7251.1-2013.
Clauses with number 101, 102, 103, etc. are the additional clauses of the corresponding ones in GB/T 7251.1-2013.
Tables and figures newly-added in this part are counted from 101.
Appendixes newly-added in this part are named by letters AA, BB, etc.
This part is, by means of translation, identical to IEC 61439-3: 2012 Low-voltage Switchgear and Controlgear Assemblies - Part 3: Part 3: Distribution Boards Intended to be Operated by Ordinary Persons (DBO).
The Chinese counterparts of the international documents given as normative references in this part are as follows:
——GB/T 2423.55-2006 Environmental Testing for Electric and Electronic Products - Part 2: Test Methods - Test Eh: Hammer Tests (IEC 60068-2-75: 1997, IDT);
——GB/T 10963.1-2005 Electrical Accessories - Circuit-breakers for Overcurrent Protection for Household and Similar Installation - Part 1: Circuit-breakers for a.c. Operation (IEC 60898-1: 2002, IDT);
——GB/T 22794-2008 Type B Residual Current Operated Circuit-breakers with and without Integral Overcurrent Protection for Household and Similar Uses (Type B RCCBs and Type B RCBOs) (IEC 62423: 2007, IDT).
The following editorial changes were made in this part:
——The contents of amendment to international standard are incorporated into this part.
This part was proposed by China Electrical Equipment Industry Association.
This part is under the jurisdiction of SAC/TC 266 National Technical Committee on Low-voltage Switchgear and Controlgear Assemblies of Standardization Administration of China.
The previous editions of the standard replaced by this Part are as follows:
——GB 7251.3-1997 and GB/T 7251.3-2006.
Low-voltage Switchgear and Controlgear Assemblies - Part 3: Distribution Boards Intended to Be Operated by Ordinary Persons (DBO)
铆螺母低压成套开关设备和控制设备
第3部分：由一般人员操作的配电板(DBO)
1 Scope
This part of GB/T 7251 defines the specific requirements for distribution boards intended to be operated by ordinary persons (DBO).
DBOs have the following criteria:
——intended to be operated by ordinary persons (e.g. switching operations and replacing fuse links), e.g. in domestic (household) applications;
——outgoing circuits contain protective devices, intended to be operated by ordinary persons, complying e.g. with IEC 60898-1, IEC 61008, IEC 61009, IEC 62423 and IEC 60269-3;
——rated voltage to earth does not exceed 300 V a.c.;
——rated current (Inc) of the outgoing circuits does not exceed 125 A and the rated current (InA) of the DBO does not exceed 250 A;
——intended for the distribution of electrical energy;
——enclosed, stationary;
——for indoor or outdoor use.
DBOs may also include control and/or signaling devices associated with the distribution of electrical energy.
This part applies to all DBOs whether they are designed, manufactured and verified on a one-off basis or fully standardized and manufactured in quantity.
DBOs may be assembled outside the factory of the original manufacturer.
This part does not apply to individual devices and self-contained components, such as circuit breakers, fuse switches, electronic equipment, etc. which will comply with the relevant product standards.
This standard does not apply to the specific types of ASSEMBLIES covered by other parts of GB/T 7251.
2 Normative References
The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
Chapter 2 of GB/T 7251.1-2013 applies except as follows.
Addition:
GB/T 7251.1-2013 Low-voltage Switchgear and Controlgear Assemblies - Part 1: General Rules (IEC 61439-1: 2011, IDT)
IEC 60068-2-75 Environmental Testing - Part 2: Tests - Test Eh: Hammer Tests
IEC 60269-3 Low-voltage Fuses - Part 3: Supplementary Requirements for Fuses for Use by Unskilled Persons (Fuses Mainly for Household and Similar Applications) - Examples of Standardized Systems of Fuses A to F
IEC 60898-1: 2010 Electrical Accessories - Circuit-breakers for Overcurrent Protection for Household and Similar Installations - Part 1: Circuit-breakers for a.c. Operation
IEC 61008 (all parts) Residual Current Operated Circuit-breakers without Integral Overcurrent Protection for Household and Similar Uses(RCCBs)
IEC 61009 (all parts) Residual Current Operated Circuit-breakers with Integral Overcurrent Protection for Household and Similar Uses(RCBOs)
IEC 62423: 2009 Type F and Type B Residual Current Operated Circuit-breakers with and without Integral Overcurrent Protection for Household and Similar Uses
3 Terms and Definitions
Chapter 3 of GB/T 7251.1-2013 applies except as follows.
3.1 General terms
Additional terms:
3.1.101
Distribution board intended to be operated by ordinary persons (DBO)
Assembly used to distribute electrical energy in domestic (household) applications and other places where operation is intended by ordinary persons
Note: Switching operations and replacing fuse-links are examples of operations intended to be carried out by normal persons.
3.1.102
Type A DBO
DBO designed to accept single pole devices
Note: In the UK, a type A DBO used principally for domestic (household) installations and having a maximum incoming unit rating of 100 A and a maximum outgoing circuit rating of 63 A, is known as a "consumer unit" or "customer distribution board".
3.1.103
Type B DBO
DBO designed to accept multi-pole and/or single pole devices
4 Symbols and Abbreviations
Chapter 4 of GB/T 7251.1-2013 applies.
5 Interface Characteristics
Chapter 5 of GB/T 7251.1-2013 applies except as follows.
5.1 General
Addition:
This objective can be achieved through one of two typical processes; the user will either select a catalogue product, the characteristics of which meet the required user needs, or make a specific agreement with the manufacturer.
In both cases, the specification schedule according to Appendix AA is intended to help the user to provide all data necessary to specify, and to help the manufacturer to characterize the actual DBO. In some cases information declared by the DBO manufacturer may take the place of an agreement.
5.2.4 Rated impulse withstand voltage (Uimp) (of the assembly)
Replacement:
The rated impulse withstand voltage shall be equal to or higher than the values stated for the transient overvoltages occurring in the electrical system(s) to which the circuit is designed to be connected.
DBO’s shall comply with a minimum overvoltage category III (see IEC 60364-4-44) according to Table G.1 of Appendix G of GB/T 7251.1-2013.
5.4 Rated diversity factor (RDF)
Addition:
In the absence of an agreement between the DBO manufacturer and user concerning the actual load currents, the assumed loading of the outgoing circuits of the DBO or group of outgoing circuits may be based on the values in Table 101.
5.6 Other characteristics
Addition:
q) type A or type B DBO (see 3.1.102 and 3.1.103).
6 Information
Chapter 6 of GB/T 7251.1-2013 applies except as follows.
6.1 Assembly designation marking
Addition to first paragraph:
The test of 10.2.7 only applies to DBOs intended for outdoor installation.
Note: In Germany and Sweden, 10.2.7 applies to DBOs intended for indoor installation.
Addition of the following new items:
e) rated current of the DBO using the symbol InA, e.g. InA 250 A;
f) degree of protection if greater than IP 2XC.
7 Service Conditions
Chapter 7 of GB/T 7251.1-2013 applies except as follows.
7.1.3 Pollution degree
Addition:
A minimum pollution degree 2 applies.
Foreword i
1 Scope
2 Normative References
3 Terms and Definitions
4 Symbols and Abbreviations
5 Interface Characteristics
6 Information
7 Service Conditions
8 Constructional Requirements
9 Performance Requirements
10 Design Verification
11 Routine Verification
Annexes
Annex D (Informative) Design Verification
Annex AA (Informative) Items Subject to Agreement between the Assembly Manufacturer and the User
Bibliography
Figure 101 Example of the Temperature Rise Verification by Test of a Complete DBO as in 10.10.2.
Table 101 Values of Assumed Loading
Table 102 Tightening Torque Vaelues for the Verification of Mechanical Strength
Table AA.1 Items Subject to Agreement between the Assembly Manufacturer and the User
GB/T 7251.3-2017 Low-voltage switchgear and controlgear assemblies-Part 3:Distribution boards intended to be operated by ordinary persons ( DBO) (English Version)
Standard No.
GB/T 7251.3-2017
Status
valid
Language
English
File Format
PDF
Word Count
10500 words
Price(USD)
260.0
Implemented on
2018-5-1
Delivery
via email in 1 business day
Detail of GB/T 7251.3-2017
Standard No.
GB/T 7251.3-2017
English Name
Low-voltage switchgear and controlgear assemblies-Part 3:Distribution boards intended to be operated by ordinary persons ( DBO)
Codeofchina.com is in charge of this English translation. In case of any doubt about the English translation, the Chinese original shall be considered authoritative.
GB/T 7251 Low-voltage Switchgear and Controlgear Assemblies consists of the following parts:
——Part 1: General Rules
——Part 3: Distribution Boards Intended to be Operated by Ordinary Persons (DBO);
——Part 4: Particular Requirements for Assemblies for Construction sites (ACS);
——Part 5: Assemblies for Power Distribution in public Networks;
——Part 6: Busbar Trunking Systems (Busways);
——Part 7: Assemblies for Specific Applications such as Marinas, Camping Sites, Market Squares, Electric Vehicles Charging Stations.
——Part 8: General Technology Requirement for Intelligent Assemblies;
——Part 10: Guidance to Specifying Assemblies;
——Part 12: Power Switchgear and Controlgear Assemblies
This part is Part 3 of GB/T 7251.
This part is developed in accordance with the rules given in GB/T 1.1-2009.
This part replaces GB/T 7251.3-2006 Low-voltage Switchgear and Controlgear Assemblies - Part 3: Particular Requirements for Low-voltage Switchgear and Controlgear Assemblies Intended to Be Installed in Places Where Unskilled Persons Have Access for Their Use - Distribution Boards; the following technical changes have been made with respect to GB/T 7251.3-2006 (the previous edition):
——The relevant structure and technical contents are adjusted according to GB/T 7251.1-2013.
This part is used in conjunction with GB/T 7251.1-2013.The general rules of GB/T 7251.1-2013 are applicable to only the scope where they are cited. If chapter and clause, figure as well as Appendix of general rules are to be used, it shall be made clear by reference to GB/T 7251.1-2013, e.g. 1.2.3 of GB/T 7251.1-2013, Table 4 of GB/T 7251.1-2013 or Appendix A of GB/T 7251.1-2013.
Clauses with number 101, 102, 103, etc. are the additional clauses of the corresponding ones in GB/T 7251.1-2013.
Tables and figures newly-added in this part are counted from 101.
Appendixes newly-added in this part are named by letters AA, BB, etc.
This part is, by means of translation, identical to IEC 61439-3: 2012 Low-voltage Switchgear and Controlgear Assemblies - Part 3: Part 3: Distribution Boards Intended to be Operated by Ordinary Persons (DBO).
The Chinese counterparts of the international documents given as normative references in this part are as follows:
——GB/T 2423.55-2006 Environmental Testing for Electric and Electronic Products - Part 2: Test Methods - Test Eh: Hammer Tests (IEC 60068-2-75: 1997, IDT);
——GB/T 10963.1-2005 Electrical Accessories - Circuit-breakers for Overcurrent Protection for Household and Similar Installation - Part 1: Circuit-breakers for a.c. Operation (IEC 60898-1: 2002, IDT);
——GB/T 22794-2008 Type B Residual Current Operated Circuit-breakers with and without Integral Overcurrent Protection for Household and Similar Uses (Type B RCCBs and Type B RCBOs) (IEC 62423: 2007, IDT).
The following editorial changes were made in this part:
——The contents of amendment to international standard are incorporated into this part.
This part was proposed by China Electrical Equipment Industry Association.
This part is under the jurisdiction of SAC/TC 266 National Technical Committee on Low-voltage Switchgear and Controlgear Assemblies of Standardization Administration of China.
The previous editions of the standard replaced by this Part are as follows:
——GB 7251.3-1997 and GB/T 7251.3-2006.
Low-voltage Switchgear and Controlgear Assemblies - Part 3: Distribution Boards Intended to Be Operated by Ordinary Persons (DBO)
铆螺母低压成套开关设备和控制设备
第3部分：由一般人员操作的配电板(DBO)
1 Scope
This part of GB/T 7251 defines the specific requirements for distribution boards intended to be operated by ordinary persons (DBO).
DBOs have the following criteria:
——intended to be operated by ordinary persons (e.g. switching operations and replacing fuse links), e.g. in domestic (household) applications;
——outgoing circuits contain protective devices, intended to be operated by ordinary persons, complying e.g. with IEC 60898-1, IEC 61008, IEC 61009, IEC 62423 and IEC 60269-3;
——rated voltage to earth does not exceed 300 V a.c.;
——rated current (Inc) of the outgoing circuits does not exceed 125 A and the rated current (InA) of the DBO does not exceed 250 A;
——intended for the distribution of electrical energy;
——enclosed, stationary;
——for indoor or outdoor use.
DBOs may also include control and/or signaling devices associated with the distribution of electrical energy.
This part applies to all DBOs whether they are designed, manufactured and verified on a one-off basis or fully standardized and manufactured in quantity.
DBOs may be assembled outside the factory of the original manufacturer.
This part does not apply to individual devices and self-contained components, such as circuit breakers, fuse switches, electronic equipment, etc. which will comply with the relevant product standards.
This standard does not apply to the specific types of ASSEMBLIES covered by other parts of GB/T 7251.
2 Normative References
The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
Chapter 2 of GB/T 7251.1-2013 applies except as follows.
Addition:
GB/T 7251.1-2013 Low-voltage Switchgear and Controlgear Assemblies - Part 1: General Rules (IEC 61439-1: 2011, IDT)
IEC 60068-2-75 Environmental Testing - Part 2: Tests - Test Eh: Hammer Tests
IEC 60269-3 Low-voltage Fuses - Part 3: Supplementary Requirements for Fuses for Use by Unskilled Persons (Fuses Mainly for Household and Similar Applications) - Examples of Standardized Systems of Fuses A to F
IEC 60898-1: 2010 Electrical Accessories - Circuit-breakers for Overcurrent Protection for Household and Similar Installations - Part 1: Circuit-breakers for a.c. Operation
IEC 61008 (all parts) Residual Current Operated Circuit-breakers without Integral Overcurrent Protection for Household and Similar Uses(RCCBs)
IEC 61009 (all parts) Residual Current Operated Circuit-breakers with Integral Overcurrent Protection for Household and Similar Uses(RCBOs)
IEC 62423: 2009 Type F and Type B Residual Current Operated Circuit-breakers with and without Integral Overcurrent Protection for Household and Similar Uses
3 Terms and Definitions
Chapter 3 of GB/T 7251.1-2013 applies except as follows.
3.1 General terms
Additional terms:
3.1.101
Distribution board intended to be operated by ordinary persons (DBO)
Assembly used to distribute electrical energy in domestic (household) applications and other places where operation is intended by ordinary persons
Note: Switching operations and replacing fuse-links are examples of operations intended to be carried out by normal persons.
3.1.102
Type A DBO
DBO designed to accept single pole devices
Note: In the UK, a type A DBO used principally for domestic (household) installations and having a maximum incoming unit rating of 100 A and a maximum outgoing circuit rating of 63 A, is known as a "consumer unit" or "customer distribution board".
3.1.103
Type B DBO
DBO designed to accept multi-pole and/or single pole devices
4 Symbols and Abbreviations
Chapter 4 of GB/T 7251.1-2013 applies.
5 Interface Characteristics
Chapter 5 of GB/T 7251.1-2013 applies except as follows.
5.1 General
Addition:
This objective can be achieved through one of two typical processes; the user will either select a catalogue product, the characteristics of which meet the required user needs, or make a specific agreement with the manufacturer.
In both cases, the specification schedule according to Appendix AA is intended to help the user to provide all data necessary to specify, and to help the manufacturer to characterize the actual DBO. In some cases information declared by the DBO manufacturer may take the place of an agreement.
5.2.4 Rated impulse withstand voltage (Uimp) (of the assembly)
Replacement:
The rated impulse withstand voltage shall be equal to or higher than the values stated for the transient overvoltages occurring in the electrical system(s) to which the circuit is designed to be connected.
DBO’s shall comply with a minimum overvoltage category III (see IEC 60364-4-44) according to Table G.1 of Appendix G of GB/T 7251.1-2013.
5.4 Rated diversity factor (RDF)
Addition:
In the absence of an agreement between the DBO manufacturer and user concerning the actual load currents, the assumed loading of the outgoing circuits of the DBO or group of outgoing circuits may be based on the values in Table 101.
5.6 Other characteristics
Addition:
q) type A or type B DBO (see 3.1.102 and 3.1.103).
6 Information
Chapter 6 of GB/T 7251.1-2013 applies except as follows.
6.1 Assembly designation marking
Addition to first paragraph:
The test of 10.2.7 only applies to DBOs intended for outdoor installation.
Note: In Germany and Sweden, 10.2.7 applies to DBOs intended for indoor installation.
Addition of the following new items:
e) rated current of the DBO using the symbol InA, e.g. InA 250 A;
f) degree of protection if greater than IP 2XC.
7 Service Conditions
Chapter 7 of GB/T 7251.1-2013 applies except as follows.
7.1.3 Pollution degree
Addition:
A minimum pollution degree 2 applies.
Contents of GB/T 7251.3-2017
Foreword i
1 Scope
2 Normative References
3 Terms and Definitions
4 Symbols and Abbreviations
5 Interface Characteristics
6 Information
7 Service Conditions
8 Constructional Requirements
9 Performance Requirements
10 Design Verification
11 Routine Verification
Annexes
Annex D (Informative) Design Verification
Annex AA (Informative) Items Subject to Agreement between the Assembly Manufacturer and the User
Bibliography
Figure 101 Example of the Temperature Rise Verification by Test of a Complete DBO as in 10.10.2.
Table 101 Values of Assumed Loading
Table 102 Tightening Torque Vaelues for the Verification of Mechanical Strength
Table AA.1 Items Subject to Agreement between the Assembly Manufacturer and the User
