1 Scope
Within GB 7251 (all parts) for low-voltage switchgear and controlgear assemblies (assemblies), there are system and application details that are specified by the user to enable the manufacturer to produce an assembly that meets the needs and expectations of the user.
This part of GB 7251, which is a technical report identifies, from the user’s perspective, those functions and characteristics that should be defined when specifying assemblies. It provides:
an explanation of the assembly characteristics and options within GB 7251 (all parts);
a guidance on how to select the appropriate option and to define characteristics so as to meet specific application needs, using a functional approach;
an assistance in the specification of assemblies.
References within this part to the interface characteristics of an assembly and the requirements with which they will comply assume that the assembly is designed, manufactured, and verified in accordance with the relevant part of GB 7251.
2 Normative References
The following documents, in whole or in part, are normatively referenced in this document and are indispensable for its application. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
GB 7251.1-2013 Low-voltage switchgear and controlgear assemblies — Part 1: General Rules (IEC 61439-1:2011, IDT)
IEC 60364-4-41 Low-voltage electrical installations — Part 4-41: Protection for safety — Protection against electric shock
IEC 60364-6 Low-voltage electrical installations — Part 6: Verification
IEC 60445 Basic and safety principles for man-machine interface, marking and identification — Identification of equipment terminals, conductor terminations and conductors
IEC 60529 Degrees of protection provided by enclosures (IP Code)
IEC 62262 Degrees of protection provided by enclosures for electrical equipment against external mechanical impacts (IK code)
CISPR 11 Industrial, scientific and medical equipment — Radio-frequency disturbance characteristics — Limits and methods of measurement
3 Terms and Definitions
For the purposes of this document, the terms and definitions given in the relevant assembly standard apply (e.g. GB 7251.12).
4 Application of Assemblies within GB 7251 (All Parts)
Foreword III
Introduction V
1 Scope
2 Normative References
3 Terms and Definitions
4 Application of Assemblies within GB 7251 (All Parts)
5 Electrical System
6 Short-circuit Withstand Capability
7 Protection of Persons Against Electric Shock
8 Installation Environment
9 Installation Method
10 Storage and Handling
11 Operating Arrangements
12 Maintenance and Upgrade Capabilities
13 Current Carrying Capability
14 Assembly Design and Routine Verification Processes
Appendix A (Informative) Cross-section of Copper Conductors Suitable for Connection to Terminals for External Conductors
Appendix B (Informative) Forms of Internal Separation (See 12.8)
Appendix C (Informative) Specification guidance for GB 7251.12
Appendix D (Informative) Specification Guidance for GB 7251.3
Appendix E (Informative) Specification Guidance for GB 7251.4
Appendix F (Informative) Specification Guidance for GB 7251.5
Appendix G (Informative) Specification Guidance for GB 7251.6
Appendix H (Informative) Specification Guidance for GB 7251.7
Appendix I (Informative) List of Notes Concerning Certain Countries
Bibliography
Figure 1 Required Rated Impulse Withstand Voltage
Figure B.1 Symbols Used in Figures B.2 and B.3
Figure B.2 Forms 1 and 2
Figure B.3 Forms 3 and 4
Table A.1 Cross-section of Copper Conductors Suitable for Connection to Terminals for External Conductors
Table B.1 Forms of Internal Separation
Table C.1 Items Subject to Agreement between the Assembly Manufacturer and the User
Table C.2 Examples of Optional Items Subject to Agreement between the Assembly Manufacturer and the User
Table D.1 Items Subject to Agreement between the Assembly Manufacturer and the User
Table E.1 Items Subject to Agreement between the Assembly Manufacturer and the User
Table G.1 Items Subject to Agreement between the Assembly Manufacturer and the User
Table I.1 List of Notes Concerning Certain Countries
