GB 50169-1992 Specification for construction and acceptance of grounding devices for electrical installation engineering GB50169-92
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Engineering Construction Standard Full-text Information System
National Standard of the People's Republic of China
50169—92
Electrical Installation Engineering
Erection works of electrical installationsCode for construction and acceptanceof earthing devices
1992—12—26
1993-—07-01
State Administration of Technical Supervision
Ministry of Construction of the People's Republic of China
Engineering Construction Standards Full-text Information System
Jointly Released
Engineering Construction Standards Full-text Information System
National Standards of the People's Republic of China
Electrical Installation Engineering
Construction and Acceptance Specifications for Grounding Devices
5016992
Editor Department: Ministry of Energy of the People's Republic of ChinaApproval Department: Ministry of Construction of the People's Republic of ChinaEffective Date: July 1, 1993
Engineering Construction Standards Full-text Information System
Engineering Construction Standards Full-text Information System
About the Release of National Standards "Construction and Acceptance Specifications for Rotating Electric Machines in Electrical Installation Engineering" and Other
Five National Notice on National Standardswww.bzxz.net
Construction Standards [1992] No. 911
In accordance with the requirements of the State Planning Commission's Letter of Planning and Standards (1987) No. 78 and the Ministry of Construction's (88) Construction Standards No. 25, five standards, including the "Specifications for Construction and Acceptance of Rotating Electrical Machines for Electrical Installation Engineering" jointly formulated by the Ministry of Energy and relevant departments, have been reviewed by relevant departments and are now approved as mandatory national standards, namely the "Specifications for Construction and Acceptance of Rotating Electrical Machines for Electrical Installation Engineering" GB50170-92, the "Specifications for Construction and Acceptance of Panels, Cabinets and Secondary Circuit Connections for Electrical Installation Engineering" GB50171-92, the "Specifications for Construction and Acceptance of Storage Batteries for Electrical Installation Engineering" GB50172-92, the "Specifications for Construction and Acceptance of Cable Lines for Electrical Installation Engineering" GB50168-92 and the "Specifications for Construction and Acceptance of Grounding Devices for Electrical Installation Engineering" GB50169-92, as mandatory national standards for implementation on July 1, 1993. The third chapter of the original "Electrical Installation Engineering Construction and Acceptance Specifications" on rotating machines, the fourth chapter on panels, cabinets and secondary circuit connections, the fifth chapter on batteries, the eleventh chapter on cable lines and the fifteenth chapter on grounding devices are abolished at the same time. This standard is managed by the Ministry of Energy, and the specific interpretation and other work is the responsibility of the Ministry of Energy's Electric Power Construction Research Institute. The publication and distribution is organized by the Ministry of Construction's Standards and Norms Research Institute. Ministry of Construction of the People's Republic of China
December 16, 1992
Engineering Construction Standards Full Text Information System
Engineering Construction Standards Full Text Information System
Revision Notes
This standard is edited by the former Ministry of Water Resources and Electric Power in accordance with the requirements of the State Planning Commission's Bidding Letter (1987) No. 78 and the Ministry of Construction's (88) Jianbiaozi No. 25. It is specifically compiled by the Ministry of Energy's Electric Power Construction Research Institute in conjunction with relevant units. During the revision process, the specification group conducted extensive investigations and studies, carefully summarized the experience since the implementation of the original specification, absorbed some scientific research results, and widely solicited opinions from relevant units across the country. Finally, our department reviewed and finalized it together with relevant departments. This specification is divided into three chapters and two appendices. The main contents of this revision are: adding grounding regulations for new equipment, using IEC standards and national standards for grounding line color markings, revising the anti-corrosion issues and welding quality requirements for grounding device construction, and making regulations on soil corrosiveness classification and quantitative and chemical resistance reducing agents. If you find any deficiencies during the implementation of this specification, please send your opinions and relevant materials directly to the management unit of this specification: the Electric Power Construction Research Institute of the Ministry of Energy (Beijing Liangxiang, Postal Code 102401) for reference in future revisions. Ministry of Energy
December 1990
Engineering Construction Standards Full Text Information System
Engineering Construction Standards Full Text Information System
Chapter 1
Chapter 2
Electrical Equipment Grounding
Section 1
Section 2
Section 3
Section 4
Section 5
Section 6
Chapter 3
Appendix—
Appendix 2
General Provisions
Selection of Grounding Device
Laying of Grounding Device
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Connection of Grounding Body (Wire)
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Acceptance and Handover of Grounding Projects for Portable and Mobile Electrical Equipment
Glossary
Explanation of Terms Used in This Code
Additional Notes
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Engineering Construction Standards Full-text Information System
Chapter 1 General
Article 1.0.1 This code is formulated to ensure the construction quality of grounding device installation projects, promote the improvement of engineering construction technology, and ensure the safe operation of grounding devices. Article 1.0.2 This specification applies to the construction and acceptance of the installation of grounding devices for electrical installations.
Article 1.0.3 The installation of grounding devices shall be carried out in accordance with the approved design. Article 1.0.4 The equipment used shall comply with the provisions of the current national technical standards and shall have a certificate of conformity.
Article 1.0.5 The safety and technical measures during construction shall comply with the provisions of this specification and the current relevant safety and technical standards.
Article 1.0.6 The installation of grounding devices shall be coordinated with the construction of building projects, and the concealed parts must be inspected and accepted in conjunction with the relevant units before covering. Article 1.0.7 The construction and acceptance of grounding devices shall comply with the provisions of the current relevant national standards and specifications in addition to the provisions of this specification. Engineering Construction Standard Full Text Information System
Engineering Construction Standard Full Text Information System
Chapter 2 Grounding of Electrical Installations
Section 1 General Provisions
Article 2.1.1 The following metal parts of electrical installations shall be grounded or zeroed: metal bases and shells of motors, transformers, electrical appliances, portable or mobile electrical appliances, etc.
2. Transmission devices of electrical equipment.
3. Metal or reinforced concrete frames of indoor and outdoor power distribution devices, as well as metal fences and metal doors close to live parts.
4. Metal frames and bases of panels (cabinets, boxes) and operating tables for power distribution, control and protection.
5. Metal shells of junction boxes, terminal heads and expanders of AC and DC power cables, metal sheaths of cables, accessible metal protection tubes for cables and steel pipes for threading. 6. Cable bridges, brackets and well frames.
7. Power line towers equipped with lightning arresters. 8. Power equipment installed on distribution line poles. 9. Metal towers and reinforced concrete towers of overhead power lines with low ground current without lightning arresters in residential areas with non-asphalt ground. 10. Frames of electrostatic precipitators.
11. Enclosed busbar casing and other exposed metal parts. 12. Metal boxes of sulfur hexafluoride enclosed combination electrical appliances and box-type substations. 13. Metal casings of electric heating equipment.
14. Metal sheaths of control cables.
Section 2.1.2. The following metal parts of electrical devices may not be grounded or zeroed: 1. In dry rooms with poorly conductive floors such as wood and asphalt, the outer shell of electrical equipment with an AC rated voltage of 380V or less or a DC rated voltage of 440V or less, but when it is possible to touch the outer shell of the above electrical equipment and other grounded objects at the same time, it should still be grounded.
2. In dry places, the outer shell of electrical equipment with an AC rated voltage of 127V or less or a DC rated voltage of 110V or less. 3. The outer shell of electrical measuring instruments, relays and other low-voltage electrical appliances installed on distribution panels, control panels and distribution devices, as well as the metal base of insulators that will not cause dangerous voltage on the support when insulation damage occurs. 4. Equipment installed on a grounded metal frame, such as wall bushings. 5. Metal brackets in battery rooms with a rated voltage of 220V or less. 6. Railway tracks drawn from power plants, substations and industrial and enterprise areas.
7. The housings of motors and electrical appliances that have reliable electrical contact with grounded machine tools and machine bases.
Article 2.1.3 The grounding device of a DC system that needs to be grounded shall meet the following requirements:
The grounding wire that can form a closed loop with the ground and that often flows current should be laid along the insulating pad and shall not have metal connections with metal pipes, buildings and equipment components.
2. In places where the soil contains corrosive substances that can be produced during electrolysis, it is not appropriate to lay grounding devices. If necessary, external grounding devices or measures to improve the soil can be taken.
3. The neutral line dedicated to the DC power circuit and the grounding body and grounding wire of the DC two-wire positive pole shall not have metal connections with the natural grounding body: when there is no insulating isolation device, the distance between them should not be less than 1m.
4. The neutral line of the three-wire DC circuit should be directly grounded. Article 2.1.4 The grounding wire should not be used for other purposes. Section 2 Selection of Grounding Devices
Article 2.2.1
The grounding of AC electrical equipment can use the following natural grounding Engineering Construction Standard Full Text Information System
Engineering Construction Standard Full Text Information System
1. Metal pipes laid underground, but not including pipes with flammable or explosive substances.
2. Metal well pipes.
3. Metal structures of buildings that are reliably connected to the earth. 4. Metal pipes and piles of hydraulic structures and similar structures. Article 2.2.2 The grounding wire of AC electrical equipment can use the following grounding bodies for grounding:
Metal structures (beams, columns, etc.) of buildings and steel bars inside concrete structures specified in the design.
2. Metal structures such as the tracks of production cranes, the shells of distribution devices, corridors, platforms, elevator vertical joints, the frames of cranes and elevators, the steel beams of conveyor belts, and the frames of electrostatic precipitators.
3. Steel pipes for wiring.
Article 2.2.3 Grounding devices should be made of steel. The conductor cross-section of the grounding device should meet the requirements of thermal stability and mechanical strength, but should not be less than the specifications listed in Table 2.2.3. Grounding devices in large and medium-sized power plants, 110kV and above substations or places with strong corrosiveness should use hot-dip galvanized steel, or increase the cross-section appropriately. Minimum specifications of steel grounding bodies and grounding wires
Types, specifications and units
Diameter of round steel (mm)
Surface (mm2)
Height (mm)
Thickness of angle steel (mm)
Thickness of steel pipe wall (mm)
AC current loop
DC current loop
Note: The cross-section of the lead-out wire of the grounding body of the power line tower should not be less than 50mm2, and the lead-out wire should be hot-dip galvanized. Engineering Construction Standard Full Text Information System
Engineering Construction Standard Full Text Information System
Article 2.2.4 The minimum cross-section of copper and aluminum grounding wires exposed on the ground of low-voltage electrical equipment shall comply with the provisions of Table 2.2.4.
The minimum cross-section of copper and aluminum grounding wires exposed on the ground of low-voltage electrical equipment
Exposed bare conductor
Insulated conductor
The grounding core of the cable or the grounding core of the multi-core wire wrapped in the same protective shell as the phase line Copper (mm2)
Aluminum (mm2)
Bare aluminum conductors shall not be used as grounding bodies or grounding underground Article 2.2.5
Article 2.2.6 When using chemical methods to reduce soil resistivity, the resistance reducing agent used shall meet the following requirements:
1. The selection of materials shall meet the design requirements. 2. The materials used must meet the current national technical standards and have qualified certificates.
3. Strictly follow the operating process specified in the manufacturer's instructions for use. Article 2.2.7 The metal skin or metal mesh of the pipeline insulation layer and the metal sheath of the cable shall not be used as the grounding wire. Section 3 Laying of grounding devices
Article 2.3.1 The buried depth of the top surface of the grounding body shall comply with the design requirements. When there is no regulation, it should not be less than 0.6m. Angle steel and steel pipe grounding bodies should be arranged vertically. In addition to the grounding body, the vertical part of the grounding body lead wire and the welding part of the grounding device should be treated with anti-corrosion; before the anti-corrosion treatment, the surface must be rusted and the residual flux at the welding point must be removed. Article 2.3.2 The spacing between vertical grounding bodies should not be less than 2 times their length. The spacing between horizontal grounding bodies should comply with the design requirements. When there is no design requirement, it should not be less than the engineering construction standard full text information system
engineering construction standard full text information system
Article 2.3.3 The grounding wire should be protected from mechanical damage and chemical corrosion. Where the grounding wire crosses roads, railways or pipelines, or where other grounding wires may be damaged, pipes or angle steels shall be used for protection. Where the grounding wire passes through walls, floors and ground, steel pipes or other strong protective sleeves shall be installed, and anti-corrosion measures shall be taken in chemically corrosive areas.
Article 2.3.4 The grounding trunk line shall be connected to the grounding grid at two or more different points. The natural grounding body shall be connected to the grounding trunk line or grounding grid at two or more different points.
Article 2.3.5 The grounding of each electrical device shall be connected to the grounding trunk line with a separate grounding wire, and several electrical devices that need to be grounded shall not be connected in series in one grounding wire.
Article 2.3.6 The backfill soil of the trench after the grounding body is laid shall not contain stones and construction waste, and the soil taken from outside shall not be highly corrosive. The backfill soil shall be compacted in layers.
Article 2.3.7 The installation of the exposed grounding wire shall meet the following requirements: 1. It shall be easy to check.
2. The laying position should not hinder the disassembly and maintenance of the equipment. 3. The distance between the supports should be 0.5~1.5m in the horizontal straight section; 1.5~3m in the vertical section; and 0.3~0.5m in the turning section. 4. The grounding wire should be laid horizontally or vertically, and can also be laid parallel to the inclined structure of the building; there should be no ups and downs and bends on the straight section. 5. When the grounding wire is laid horizontally along the wall of the building, the distance from the ground should be 250~300mm; the gap between the grounding wire and the wall of the building should be 10~15mm. 6. When the grounding wire crosses the expansion joint and settlement joint of the building, a compensator should be installed. The compensator can be replaced by the grounding wire itself bent into an arc. Article 2.3.8 The surface of the exposed grounding wire should be painted with green and yellow stripes of equal width of 15~100mm. It is advisable to make marks on the entire length of each conductor or only in each section or each accessible part. When using tape, engineering construction standard full text information system
engineering construction standard full text information system
should use two-color tape.
Neutral wire should be painted with light blue mark.
Article 2.3.9 At the entrance of the grounding wire to the building and at the temporary grounding point for maintenance, white primer should be painted and marked with black marks, and its code is "α". Article 2.3.10 During maintenance, grounding wires should be introduced in places where temporary grounding is required, such as circuit breaker rooms, power distribution rooms, busbar sections, generator lead-out lines, etc., and terminal blocks and bolts specially used for connecting temporary grounding wires should be provided. Article 2.3.11 When the cable passes through the zero-sequence current transformer, the grounding wire at the cable head should be grounded after passing through the zero-sequence current transformer: the metal sheath and grounding wire of the cable from the cable head to the section passing through the zero-sequence current transformer should be insulated from the ground. Article 2.3.12 The neutral point of transformers and rotating motors that are directly grounded or grounded through arc suppression coils shall be connected to the grounding body or grounding trunk line using a separate grounding wire.
Article 2.3.13
The lightning arrester of the substation and distribution station shall be connected to the main grounding grid using the shortest grounding wire.
Article 2.3.14
The casing of the fully enclosed combination electrical appliance shall be grounded according to the manufacturer's regulations; the flanges shall be connected using jumper wires, and a good electrical path shall be ensured. Article 2.3.Article 15 Soft copper wires should be used to connect the hinges of the fence doors of high-voltage distribution intervals and static compensation devices to maintain good grounding. Article 2.3.16 The shielding nets of high-frequency induction heating devices, filters, metal shielding shells of power supply devices, exposed conductors in high-frequency circuits, all shielding parts of electrical equipment and metal pipes connected to them should be grounded and should be connected to the grounding trunk line. Article 2.3.17 When the grounding device consists of multiple sub-grounding device parts, disconnect cards that are easy to separate should be set according to design requirements. There should be disconnect cards that are easy to separate at the connection between the natural grounding body and the artificial grounding body. The disconnect card should have protective measures. Section 4 Connection of grounding bodies (wires)
Article 2.4.1 The connection of grounding bodies (wires) should be welded, and the welding must be firm Engineering Construction Standards Full Text Information System
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