Substation cable distribution boards (SCDBs) and cable distribution cabinets (CDCs) for power distribution in public networks shall comply with all the requirements of GB 7251.1-2005 and shall also comply with the particular requirements contained in this part.
This part gives supplementary requirements for substation cable distribution boards (SCDBs) and cable distribution cabinets (CDCs), which are stationary, type-tested assemblies (TTA).They are used for the distribution of electrical energy in three-phase systems. Open-type ASSEMBLY are not covered by this part.
Individual components, such as fuses and switching devices that comply with other standards, shall also comply with the supplementary requirements of this standard.
The object of this standard is to state the definitions and to specify the service conditions, construction requirements, technical performances and tests for SCDBs and CDCs.
Higher performance and test levels may be required for particular networks, for example, those with meshed connections.
NOTE 1: If a CDC is equipped with additional equipment (for example meters), in such a way that the main function is changed considerably, then other standards may also apply as agreed between user and manufacturer (see 7.6).
NOTE 2: Where local regulations and practices permit, an SCDB or CDC according to this standard may be used in other than public networks.
SCDBs are suitable for installation in places where only skilled persons have access for their use; however, outdoor types may be installed in situations which may be accessible to the public.
SCDBs are connected to the low voltage terminals of distribution transformers by means of connecting bars, rods or cables.
CDCs are for outdoor installation in places which are accessible to the public, and where only skilled persons have access for their use.
Foreword
1 General Provisions
1.1 Scope
1.2 Normative references
2 Terms and Definitions
3 Classifications of Assemblies
4 Electrical Performances of Assemblies
5 Information to Be Given Regarding to the Assemblies
5.1 Nameplates
5.2 Markings
6 Service Conditions
7 Design and Construction
7.2 Enclosure and degree of protection
7.3 Temperature rise
7.4 Protection against electric shock
7.6 Switching devices and components installed in ASSEMBLY
8 Test Specifications
8.1 Classification of tests
8.2 Type tests
Annex A (Normative) Minimum and maximum cross-section of copper and aluminium conductors, suitable for connection
GB 7251.5-2008 引用如下标准：
* GB 7947-2010 人机界面标志标识的基本和安全规则 导体颜色或字母数字标识 * GB/T 5169.16-2008 电工电子产品着火危险试验 第16部分: 试验火焰 50W 水平与垂直火焰试验方法 * GB 13539.1-2008 低压熔断器 第1部分：基本要求 * GB/T 16422.2-2014 塑料 实验室光源暴露试验方法 第2部分：氙弧灯 * IEC 60068-2-11: 1981 Basic environmental testing procedures. Part 2: Tests. Test Ka: Salt mist (GB/T 2423.17 - 1993 equivalent to IEC 60068-2-11:1981) * IEC 60068-2-30: 2005 Environmental testing - Part 2-30: Tests - Test Db: Damp heat, cyclic (12 h + 12 h cycle) (GB/T 2423.4 - 1993 equivalent to IEC 60068-2-30: 1980) * IEC 60238: 2004 Edison screw lamp holders * ISO 3231: 1993 Paints and varnishes -- Determination of resistance to humid atmospheres containing sulfur dioxide * ISO 4628-3: 2003 Paints and varnishes -- Evaluation of degradation of coatings -- Designation of quantity and size of defects, and of intensity of uniform changes in appearance -- Part 3: Assessment of degree of rusting * ISO 6506-1: 2005 Metallic materials -- Brinell hardness test -- Part 1: Test method * ISO 9223: 1992 Corrosion of metals and alloys -- Corrosivity of atmospheres – Classification
