GB/T 7251.1-2023 English PDF (GBT7251.1-2023)

Delivery: 3 seconds. Download true-PDF + Invoice.
Get QUOTATION in 1-minute: Click GB/T 7251.1-2023
Historical versions: GB/T 7251.1-2023
Preview True-PDF (Reload/Scroll if blank)

GB/T 7251.1-2023: Low-voltage switchgear and controlgear assemblies - Part 1: General rules
GB/T 7251.1-2023
GB
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 29.130.20
CCS K 31
GB/T 7251.1-2023 / IEC 61439-1:2020
Replacing GB/T 7251.1-2013
Low-Voltage Switchgear and Controlgear Assemblies – Part
1: General Rules
(IEC 61349-1:2020, IDT)
ISSUED ON: AUGUST 6, 2023
IMPLEMENTED ON: MARCH 1, 2024
Issued by: State Administration for Market Regulation;
Standardization Administration of the People’s Republic of China.
Table of Contents
Foreword ... 7
Introduction ... 11
1 Scope ... 13
2 Normative References ... 14
3 Terms and Definitions ... 19
4 Symbols and Abbreviations ... 40
5 Interface Characteristics ... 42
5.1 General ... 42
5.2 Voltage ratings ... 42
5.2.1 Rated voltage (Un) (of the assembly) ... 42
5.2.2 Rated operational voltage (Ue) (of a circuit of an assembly) ... 42
5.2.3 Rated insulation voltage (Ui) (of a circuit of an assembly) ... 42
5.2.4 Rated impulse withstand voltage (Uimp) (of the assembly) ... 42
5.3 Current ratings ... 43
5.3.1 Rated current of an assembly (InA) ... 43
5.3.2 Rated current of a main outgoing circuit (Inc) ... 43
5.3.3 Group rated current of a main circuit (Ing) ... 43
5.3.4 Rated peak withstand current (Ipk) ... 44
5.3.5 Rated short-time withstand current (Icw) (of a main circuit of an assembly) ... 44
5.3.6 Rated conditional short-circuit current (Icc) (of an assembly or a circuit of an
assembly) ... 45
5.4 Rated diversity factor (RDF) ... 45
5.5 Rated frequency (fn) ... 45
5.6 Other characteristics ... 46
6 Information ... 46
6.1 Assembly designation marking ... 46
6.2 Documentation ... 47
6.2.1 Information relating to the assembly ... 47
6.2.2 Instructions for handling, installation, operation and maintenance ... 47
6.3 Device and/or component identification ... 48
7 Service Conditions ... 48
7.1 Normal service conditions ... 48
7.1.1 Climatic conditions ... 48
7.1.2 Pollution degree ... 49
7.2 Special service conditions ... 49
7.3 Conditions during transport, storage and installation ... 50
8 Constructional Requirements ... 50
8.1 Strength of materials and parts ... 50
8.1.1 General ... 50
8.1.2 Protection against corrosion ... 51
8.1.3 Properties of insulating materials ... 51
8.1.4 Resistance to ultra-violet (UV) radiation ... 52
8.1.5 Mechanical strength ... 52
8.1.6 Lifting provision ... 53
8.2 Degree of protection provided by an assembly enclosure ... 53
8.2.1 Protection against mechanical impact (IK code) ... 53
8.2.2 Protection against contact with live parts, ingress of solid foreign bodies and water
(IP code) ... 53
8.2.3 Assembly with removable parts ... 54
8.3 Clearances and creepage distances ... 54
8.3.1 General ... 54
8.3.2 Clearances ... 55
8.3.3 Creepage distances ... 55
8.4 Protection against electric shock ... 56
8.4.1 General ... 56
8.4.2 Basic protection ... 56
8.4.3 Fault protection ... 57
8.4.4 Additional requirements for class II assemblies ... 61
8.4.5 Limitation of steady-state touch currents and charge ... 62
8.4.6 Operating and servicing conditions ... 62
8.5 Incorporation of switching devices and components ... 64
8.5.1 Fixed parts ... 64
8.5.2 Removable parts ... 65
8.5.3 Selection of switching devices and components ... 65
8.5.4 Installation of switching devices and components ... 66
8.5.5 Accessibility ... 66
8.5.6 Barriers ... 66
8.5.7 Direction of operation and indication of switching positions ... 67
8.5.8 Indicator lights and push-buttons ... 67
8.5.9 Power factor correction banks ... 67
8.6 Internal electrical circuits and connections ... 67
8.6.1 Main circuits ... 67
8.6.2 Auxiliary circuits ... 68
8.6.3 Bare and insulated conductors ... 68
Foreword
This Document was drafted as per the rules specified in GB/T 1.1-2020 Directives for
Standardization – Part 1: Rules for the Structure and Drafting of Standardizing Documents.
This Document is Part 1 of GB/T 7251 Low-Voltage Switchgear and Controlgear Assemblies.
GB/T 7251 has published the following parts:
--- Part 1: General Rules;
--- Part 2: Power Switchgear and Controlgear Assemblies;
--- 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 Station;
--- Part 8: General Technical Requirements for Intelligent Assembly;
--- Part 10: Guidance to Specifying Assemblies.
This Document replaced GB/T 7251.1-2013 Low-Voltage Switchgear and Controlgear
Assemblies - Part 1: General Rules. Compared with GB/T 7251.1-2013, the major technical
changes of this Document are as follows besides the structural adjustments and editorial
modifications:
--- Change the scope of the document, and add the description of the inapplicability of this
document to the scope, such as power electronic converter systems and equipment
(PECS), switch mode power supplies (SMPS), uninterruptible power supplies (UPS),
basic drive modules (BDM), complete drive modules (CDM), adjustable speed electrical
power drive systems (PDS), and other electronic equipment; (see Clause 1 of this Edition;
Clause 1 of the 2013 Edition);
--- Add the definition of the rated current of the main circuit group of the complete
equipment (see 3.8.10.6 of this Edition);
--- Add the interface characteristics of the rated current of the main circuit group of the
complete equipment (see 5.3.3 of this Edition);
--- Change the requirements and temperature rise verification related to the new
characteristic of the group rated current (see 3.8.11, 5.3.1, 5.3.2, 5.4 of this Edition;
3.8.11, 5.3.1, 5.3.2, 5.4 of the 2013 Edition; see 10.10.1, 10.10.2.3, 10.10.4, Annex L of
this Edition; 10.10.1, 10.10.2.3, 10.10.4, Annex O of the 2013 Edition);
--- Change the relevant provisions related to DC (see 3.7.18, 3.8.9.2, 3.8.10.3, 5.3.5, 9.3.3,
10.9.2, 10.9.3, 10.11.2, 10.11.5.4, Table 9 of this Edition; 3.8.9.2, 3.8.10.3, 5.3.4, 9.3.3,
10.9.2, 10.9.3, 10.11.5.4, Table 9 of the 2013 Edition);
--- Change the relevant provisions on electric shock protection, introduce the concept of
Class I and Class II complete sets of equipment for electric shock protection, and increase
the corresponding requirements and verifications for such complete sets of equipment.
(see 3.7.24, 3.7.25, 8.4.3, 10.11.5.6 of this Edition; 8.4.3, 10.11.5.6 of the 2013 Edition).
This Document equivalently adopted IEC 61439-1:2020 Low-Voltage Switchgear and
Controlgear Assemblies – Part 1: General Rules.
The following minimal editorial changes were made to this Document:
--- The technical corrigendum of IEC 61439-1:2020/COR1:2021 is incorporated, and the
outer margin positions of the involved clauses are marked with vertical double lines (||).
Please note some contents of this Document may involve patents. The issuing agency of this
Document shall not assume the responsibility to identify these patents.
This Document was proposed by China Electrical Equipment Industrial Association.
This Document shall be under the jurisdiction of National Technical Committee on Low-
Voltage Switchgear and Controlgear Assemblies of Standardization Administration of China
(SAC/TC 266).
Drafting organizations...