GB/T 7251.5-2025 Low-voltage switchgear and controlgear assemblies - Part 5: Assemblies for power distribution in public networks
1 Scope
This document defines the specific requirements for public electricity network distribution assemblies (PENDA).
PENDA have the following criteria:
– used for the distribution of electrical energy in three phase systems for which the rated voltage does not exceed 1 000 V AC (see Figure 101 for a typical distribution network) and DC systems not exceeding 1 500 V DC;
– stationary;
– open type assemblies are not covered by this document;
– suitable for installation in places where only skilled persons have access for their use, however, outdoor types can be installed in situations that are accessible to ordinary persons:
• intended for use in energy distribution in public power grids;
• indoor use: assemblies for installation inside of electric power substations;
• outdoor use: assemblies containing an enclosure suitable for open air installation.
The object of this document is to state the definitions and to specify the service conditions, construction requirements, technical characteristics and tests for PENDA. Tests at higher performance level can be applicable with some network parameters.
PENDA can also include control and or signalling devices associated with the distribution of electrical energy.
Note 1: Control and monitoring devices can be used in smart grid applications or the transmission of smart grid data.
This document applies to all PENDA whether they are designed, manufactured on a one-off
basis or fully standardised and manufactured in quantity.
The manufacture and/or assembly can be carried out other than by the original manufacturer (see 3.10.1 of GB/T 7251.1-2023).
This document does not apply to individual devices and self-contained components, such as motor starters, fuse switches, electronic equipment, etc. which comply with the relevant product standards.
If the substation is owned or operated by a public distribution system operator (DSO), PENDA’s which are used as LV distribution panels in transformer substations are within the scope of this document.
This document does not apply to specific types of assemblies covered by other parts of IEC 61439 series.
Figure 101 Typical distribution network
Note 2: If a PENDA is equipped with additional equipment (for example meters), in such a way that the main function is changed considerably, then other standards can also apply as agreed between user and manufacturer (see 8.5 of GB/T 7251.1-2023).
Note 3: Where local regulations and practices permit, a PENDA according to this document can be used in other than public networks.
Note 4: DSO’s can define additional requirements for their PENDA’s.
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.
This clause of GB/T 7251.1-2023 applies except as follows.
Addition:
GB/T 5169.16-2017 Fire hazard testing for electric and electronic products - Part 16:Test flames-50 W horizontal and vertical flame test methods (IEC 60695-11-10:2013, IDT)
GB/T 7251.1-2023 Low-voltage switchgear and controlgear assemblies - Part 1: General rules (IEC 61439-1:2020, IDT)
GB/T 19292.1-2018 Corrosion of metals and alloys - Corrosivity of atmospheres - Part 1: Classification, determination and estimation (ISO 9223:2012, IDT)
IEC 62262 Degrees of protection provided by enclosures for electrical equipment against external mechanical impacts (IK code)
Note: GB/T 20138-2023, Degrees of protection provided by enclosures for electrical equipment against external mechanical impacts (IK code) (IEC 62262:2021, IDT)
ISO 6506-1:2014 Metallic materials – Brinell hardness test – Part 1: Test method
Note: GB/T 231.1-2018, Metallic materials - Brinell hardness test - Part 1: Test method (ISO 6506-1:2014, MOD)
3 Terms and definitions
This clause of GB/T 7251.1-2023 applies except as follows.
3.1 General terms
Additional terms:
3.1.101
public electricity network distribution assembly; PENDA
assembly, generally for installation in a public electricity network which in use, receives electrical energy from one or more supplies and distributes that energy through one or more cables to other equipment
Note 1: A PENDA is installed, operated and maintained solely by skilled persons.
Note 2: Some types of a PENDA were previously known as a cable distribution cabinet (CDC).
3.1.101.1
outdoor public electricity network distribution assembly; PENDA-O
cubicle type public electricity network distribution assembly that is suitable for outdoor installation in places that can, or cannot, be accessible to the public
3.1.101.2
indoor public electricity network distribution assembly; PENDA-I
public electricity network distribution assembly suitable for installation indoors, generally without an enclosure, but including all structural parts necessary to support busbars, functional units and other ancillary devices, necessary to complete the assembly
3.1.102
design life
minimum duration for which specified performance characteristics of equipment are expected when the equipment is operated as intended and regularly maintained by instructed persons in accordance with the manufacturer’s instructions
[SOURCE: GB/T 2900.97-2016, 395-07-93, modified.]
3.3 External design of assemblies
3.3.1
open-type assembly
This term of GB/T 7251.1-2023 does not apply
3.9 Verification
Modifications:
3.9.1
design verification
Delete the note.
3.9.1.2
verification comparison
This term of GB/T 7251.1-2023 does not apply.
3.9.1.3
verification assessment
This term of GB/T 7251.1-2023 does not apply.
4 Symbols and abbreviations
This clause of GB/T 7251.1-2023 applies.
5 Interface characteristics
This clause of GB/T 7251.1-2023 applies, except as follows.
5.4 Rated diversity factor (RDF)
Addition:
In the absence of an agreement between the assembly manufacturer and user concerning the actual load currents, the assumed loading of the outgoing circuits of the assembly or group of outgoing circuits can be based on the values given in Table 101.
For distribution and final circuits, it is assumed that the load current is the rated current of the protective device, In , as required by the user, multiplied with the loading factor of Table 101.
Table 101 Values of assumed loading
Application Assumed loading factor
Regular distribution grid connections
2 to 3 circuits 0.9
Regular distribution grid connections
4 to 5 circuits 0.8
Regular distribution grid connections
6 to 9 circuits 0.7
Regular distribution grid connections
≥ 10 circuits 0.6
Generation supply (e,g. PV, wind farm, biomass) 1.0
Charging infrastructure for EV 1.0
6 Information
This clause of GB/T 7251.1-2023 applies except as follows.
6.1 Assembly designation marking
Addition to first paragraph:
Designation plates can be placed inside an enclosure of an assembly provided their intended place ensures good legibility and visibility when the door(s) is(are) open or the cover is removed.
Replacement of item g):
g) GB/T 7251.1.
6.3 Device and/or component identification
Additional paragraph:
In the case of removable fuse-carriers which are specific to a fuseway, a label shall be placed on the fuse carrier as well as on the fuse base, to avoid incorrect interchangeability of the fuse-carrier.
Additional subclause:
6.101 Circuit identification
It shall be possible to identify each functional unit in a clearly visible manner.
7 Service conditions
Contents
Foreword I
Introduction III
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
Annex L (informative) Guidance on verification of temperature rise
Annex AA (normative) Cross-section of conductors
Annex BB (informative) Items subject to agreement between the assembly manufacturer and the user
Annex CC (informative) Design verification
Annex DD (informative) List of notes concerning certain countries
Bibliography
Standard
GB/T 7251.5-2025 Low-voltage switchgear and controlgear assemblies—Part 5：Assemblies for power distribution in public networks (English Version)
Standard No.
GB/T 7251.5-2025
Status
to be valid
Language
English
File Format
PDF
Word Count
21000 words
Price(USD)
630.0
Implemented on
2026-7-1
Delivery
via email in 1 business day
Detail of GB/T 7251.5-2025
Standard No.
GB/T 7251.5-2025
English Name
Low-voltage switchgear and controlgear assemblies—Part 5：Assemblies for power distribution in public networks
GB/T 7251.5-2025 Low-voltage switchgear and controlgear assemblies - Part 5: Assemblies for power distribution in public networks
1 Scope
This document defines the specific requirements for public electricity network distribution assemblies (PENDA).
PENDA have the following criteria:
– used for the distribution of electrical energy in three phase systems for which the rated voltage does not exceed 1 000 V AC (see Figure 101 for a typical distribution network) and DC systems not exceeding 1 500 V DC;
– stationary;
– open type assemblies are not covered by this document;
– suitable for installation in places where only skilled persons have access for their use, however, outdoor types can be installed in situations that are accessible to ordinary persons:
• intended for use in energy distribution in public power grids;
• indoor use: assemblies for installation inside of electric power substations;
• outdoor use: assemblies containing an enclosure suitable for open air installation.
The object of this document is to state the definitions and to specify the service conditions, construction requirements, technical characteristics and tests for PENDA. Tests at higher performance level can be applicable with some network parameters.
PENDA can also include control and or signalling devices associated with the distribution of electrical energy.
Note 1: Control and monitoring devices can be used in smart grid applications or the transmission of smart grid data.
This document applies to all PENDA whether they are designed, manufactured on a one-off
basis or fully standardised and manufactured in quantity.
The manufacture and/or assembly can be carried out other than by the original manufacturer (see 3.10.1 of GB/T 7251.1-2023).
This document does not apply to individual devices and self-contained components, such as motor starters, fuse switches, electronic equipment, etc. which comply with the relevant product standards.
If the substation is owned or operated by a public distribution system operator (DSO), PENDA’s which are used as LV distribution panels in transformer substations are within the scope of this document.
This document does not apply to specific types of assemblies covered by other parts of IEC 61439 series.
Figure 101 Typical distribution network
Note 2: If a PENDA is equipped with additional equipment (for example meters), in such a way that the main function is changed considerably, then other standards can also apply as agreed between user and manufacturer (see 8.5 of GB/T 7251.1-2023).
Note 3: Where local regulations and practices permit, a PENDA according to this document can be used in other than public networks.
Note 4: DSO’s can define additional requirements for their PENDA’s.
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.
This clause of GB/T 7251.1-2023 applies except as follows.
Addition:
GB/T 5169.16-2017 Fire hazard testing for electric and electronic products - Part 16:Test flames-50 W horizontal and vertical flame test methods (IEC 60695-11-10:2013, IDT)
GB/T 7251.1-2023 Low-voltage switchgear and controlgear assemblies - Part 1: General rules (IEC 61439-1:2020, IDT)
GB/T 19292.1-2018 Corrosion of metals and alloys - Corrosivity of atmospheres - Part 1: Classification, determination and estimation (ISO 9223:2012, IDT)
IEC 62262 Degrees of protection provided by enclosures for electrical equipment against external mechanical impacts (IK code)
Note: GB/T 20138-2023, Degrees of protection provided by enclosures for electrical equipment against external mechanical impacts (IK code) (IEC 62262:2021, IDT)
ISO 6506-1:2014 Metallic materials – Brinell hardness test – Part 1: Test method
Note: GB/T 231.1-2018, Metallic materials - Brinell hardness test - Part 1: Test method (ISO 6506-1:2014, MOD)
3 Terms and definitions
This clause of GB/T 7251.1-2023 applies except as follows.
3.1 General terms
Additional terms:
3.1.101
public electricity network distribution assembly; PENDA
assembly, generally for installation in a public electricity network which in use, receives electrical energy from one or more supplies and distributes that energy through one or more cables to other equipment
Note 1: A PENDA is installed, operated and maintained solely by skilled persons.
Note 2: Some types of a PENDA were previously known as a cable distribution cabinet (CDC).
3.1.101.1
outdoor public electricity network distribution assembly; PENDA-O
cubicle type public electricity network distribution assembly that is suitable for outdoor installation in places that can, or cannot, be accessible to the public
3.1.101.2
indoor public electricity network distribution assembly; PENDA-I
public electricity network distribution assembly suitable for installation indoors, generally without an enclosure, but including all structural parts necessary to support busbars, functional units and other ancillary devices, necessary to complete the assembly
3.1.102
design life
minimum duration for which specified performance characteristics of equipment are expected when the equipment is operated as intended and regularly maintained by instructed persons in accordance with the manufacturer’s instructions
[SOURCE: GB/T 2900.97-2016, 395-07-93, modified.]
3.3 External design of assemblies
3.3.1
open-type assembly
This term of GB/T 7251.1-2023 does not apply
3.9 Verification
Modifications:
3.9.1
design verification
Delete the note.
3.9.1.2
verification comparison
This term of GB/T 7251.1-2023 does not apply.
3.9.1.3
verification assessment
This term of GB/T 7251.1-2023 does not apply.
4 Symbols and abbreviations
This clause of GB/T 7251.1-2023 applies.
5 Interface characteristics
This clause of GB/T 7251.1-2023 applies, except as follows.
5.4 Rated diversity factor (RDF)
Addition:
In the absence of an agreement between the assembly manufacturer and user concerning the actual load currents, the assumed loading of the outgoing circuits of the assembly or group of outgoing circuits can be based on the values given in Table 101.
For distribution and final circuits, it is assumed that the load current is the rated current of the protective device, In , as required by the user, multiplied with the loading factor of Table 101.
Table 101 Values of assumed loading
Application Assumed loading factor
Regular distribution grid connections
2 to 3 circuits 0.9
Regular distribution grid connections
4 to 5 circuits 0.8
Regular distribution grid connections
6 to 9 circuits 0.7
Regular distribution grid connections
≥ 10 circuits 0.6
Generation supply (e,g. PV, wind farm, biomass) 1.0
Charging infrastructure for EV 1.0
6 Information
This clause of GB/T 7251.1-2023 applies except as follows.
6.1 Assembly designation marking
Addition to first paragraph:
Designation plates can be placed inside an enclosure of an assembly provided their intended place ensures good legibility and visibility when the door(s) is(are) open or the cover is removed.
Replacement of item g):
g) GB/T 7251.1.
6.3 Device and/or component identification
Additional paragraph:
In the case of removable fuse-carriers which are specific to a fuseway, a label shall be placed on the fuse carrier as well as on the fuse base, to avoid incorrect interchangeability of the fuse-carrier.
Additional subclause:
6.101 Circuit identification
It shall be possible to identify each functional unit in a clearly visible manner.
7 Service conditions
Contents of GB/T 7251.5-2025
Contents
Foreword I
Introduction III
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
Annex L (informative) Guidance on verification of temperature rise
Annex AA (normative) Cross-section of conductors
Annex BB (informative) Items subject to agreement between the assembly manufacturer and the user
Annex CC (informative) Design verification
Annex DD (informative) List of notes concerning certain countries
Bibliography
