GB 50258-1996 Electrical installation engineering 1kv and below wiring engineering construction and acceptance specification GB50258-96
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National Standard of the People's Republic of China
Electrical Equipment Installation Engineering
Code for construction and acceptance of 1kV and under feeder cable engineering electricequipment installation engineeringGB50258—96
Editing department: Ministry of Electric Power Industry of the People’s Republic of ChinaApproving department: Ministry of Construction of the People’s Republic of ChinaEffective date: February 1, 1997
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Notice on the release of national standards “Construction and acceptance specifications for wiring projects of 1kV and below for electrical installation engineering” and “Construction and acceptance specifications for electrical lighting installations for electrical installation engineering”
Construction Standard [1996] No. 475
According to the requirements of the State Planning Commission’s Jizong [1986] No. 2630 and the Ministry of Construction’s (90) Jianbiao Jizi No. 4, the “Construction and Acceptance Specifications for Wiring Projects of 1kV and Below for Electrical Installation Engineering” and “Construction and Acceptance Specifications for Electrical Lighting Installations for Electrical Installation Engineering” jointly revised by the Ministry of Electric Power Industry and relevant departments have been reviewed by relevant departments. The "Construction and Acceptance Specifications for Wiring Engineering of 1kV and Below for Electrical Installation Engineering" GB50258-96 and "Construction and Acceptance Specifications for Electrical Lighting Installation for Electrical Installation Engineering" GB50259-96 are now approved as mandatory national standards, which will be implemented from February 1, 1997. The 13th chapter "Wiring Engineering" and the 14th chapter "Electrical Lighting Installation" of the original national standard "Construction and Acceptance Specifications for Electrical Installation Engineering" GBJ232-82 are abolished at the same time.
This specification is managed by the Ministry of Electric Power Industry, and the specific interpretation and other work is the responsibility of the Electric Power Construction Research Institute of the Ministry of Electric Power Industry, and the publication and distribution is organized by the Standard and Quota Research Institute of the Ministry of Construction.
Ministry of Construction of the People's Republic of China
August 16, 1996
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General Provisions:
Steel pipe laying.
Metal hose laying
Plastic pipe laying
General Provisions
Wire threading inside pipes
Porcelain clips, porcelain columns, porcelain bottles wiring
Trough plate wiring
Wire trough wiring
Steel cable wiring
Plastic sheathed wire laying
Project handover and acceptance
Appendix A
Appendix B
Appendix C
Appendix D
Appendix E
Minimum distance between electrical lines and pipelines
Minimum cross-section of wire cores for different laying methodsMinimum distance between outdoor insulated wires and buildings and structures
Minimum distance between indoor and outdoor insulated wiresMinimum distance between indoor and outdoor insulated wires and the groundAdditional instructions
Explanation of terms used in the specification
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1 General Principles
1.0.1 This specification is formulated to ensure the construction quality of electrical installation wiring engineering, promote technological progress, and ensure safe operation.
1.0.2 This specification applies to the construction and acceptance of 1kV and below wiring engineering in buildings and structures.
1.0.3 The construction of wiring engineering should be carried out according to the approved design. When the design is modified, it should be approved by the original design unit before it can be carried out. 1.0.4 The equipment used and its transportation and storage shall comply with the relevant provisions of the current national standards; when there are special requirements for the product, it shall also comply with the provisions of the product technical documents. 1.0.5 After the equipment arrives at the construction site, it shall be inspected according to the following requirements: 1.0.5.1 The technical documents shall be complete.
The model, specification and appearance quality shall comply with the design requirements and the provisions of this specification. 1.0.5.2
1.0.6 The safety and technical measures in the construction of wiring engineering shall comply with the provisions of this specification and the current national standards and product technical documents.
1.0.7 Before the construction of wiring engineering, the construction engineering shall comply with the following requirements: 1.0.7.1 The templates, scaffolding, etc. that affect the construction of wiring engineering shall be removed, and the debris shall be removed.
All building decoration work that may cause pollution to the wiring engineering shall be completed. 1.0.7.2
On the foundation template of large equipment with buried wire protection tubes, the reference point or reference line for measuring the coordinates and elevation of the wire protection tube outlet should be marked. 1.0.7.4 Pre-embedded parts such as wire protection tubes, brackets, bolts, etc. buried in buildings and structures should be pre-embedded during construction. 1.0.7.5 The position and size of reserved holes and embedded parts should meet the design requirements, and the embedded parts should be firmly buried.
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1.0.8 After the wiring project is completed, the holes, holes, trenches, grooves, etc. of buildings and structures caused during the construction should be repaired.
1.0.9 When the electrical line passes through the settlement joints or expansion joints of buildings and structures, a compensation device fixed at both ends should be installed, and the conductor should have a margin. 1.0.10 When the electrical circuit is laid along the surface of the heating element, the distance from the surface of the heating element shall comply with the design requirements.
1.0.11 The minimum distance between the electrical circuit and the pipeline shall comply with the provisions of Appendix A of this specification.
The ferrous metal accessories such as pipe clamps, brackets, hooks, pull rings and boxes (boxes) used in wiring engineering shall be galvanized or painted with anti-corrosion paint. 1.0.13 The grounding and zeroing of non-live metal parts in wiring engineering shall be reliable. In addition to complying with the provisions of this specification, the construction and acceptance of wiring engineering shall also comply with the provisions of the relevant national standards and specifications in force. Engineering Construction Standard Full Text Information System
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2 Piping
2.1 General provisions
2.1.1 The pipe openings and joints of the wire protection pipes laid in dusty or humid places shall be sealed.
2.1.2 When the line is concealed, the wire protection tube should be laid along the nearest route and the bends should be reduced. The distance between the wire protection tube buried in the building and structure and the surface of the building and structure should not be less than 15mm.
2.1.3 The wire protection tube entering the floor-standing distribution box should be arranged neatly, and the tube mouth should be 50~80mm higher than the foundation surface of the distribution box.
2.1.4 The wire protection tube should not pass through the foundation of equipment or buildings and structures. When it must pass through, protective measures should be taken.
2.1.5 There should be no wrinkles, depressions or cracks at the bends of the wire protection tube, and the degree of flattening should not be greater than 10% of the outer diameter of the tube.
2.1.6 The bending radius of the wire protection tube shall comply with the following provisions: 2.1.6.1 When the line is exposed, the bending radius should not be less than 6 times the outer diameter of the tube; when there is only one bend between two junction boxes, its bending radius should not be less than 4 times the outer diameter of the tube.
When the line is concealed, the bending radius should not be less than 6 times the outer diameter of the tube; when buried underground or in concrete, its bending radius should not be less than 10 times the outer diameter of the tube. 2.1.7 When the wire protection tube encounters one of the following situations, a junction box or a pull box should be added in the middle, and the location of the junction box or the pull box should be convenient for threading: 2.1.7.1 For every 30m of tube length, there is no bend. 2.1.7.2 For every 20m of tube length, there is one bend. For every 15m of tube length, there are two bends. 2.1.7.3
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2.1.7.4 For every 8m of pipe length, there are three bends. 2.1.8 When the vertically laid wire protection pipe encounters one of the following situations, a wire pull box for fixing the wire should be added:
2.1.8.1 The cross-section of the wire in the pipe is 50mm2 or less, and the length exceeds 30m. 2.1.8.2 The cross-section of the wire in the pipe is 70~95mm2, and the length exceeds 20m. 2.1.8.3 The cross-section of the wire in the pipe is 120~240mm2, and the length exceeds 18m. 2.1.9 For horizontally or vertically laid open distribution wire protection pipes, the allowable deviation of horizontal or vertical installation is 1.5%, and the total length deviation should not be greater than 1/2 of the inner diameter of the pipe.2.1.10 In TN-S and TN-CS systems, when metal wire protection tubes, metal boxes, plastic wire protection tubes, and plastic boxes are used together, the metal wire protection tubes and metal boxes must have reliable electrical connections with the protective ground wire (PE wire).
2.2 Steel pipe laying
2.2.1 Thick-walled steel tubes or liquid-proof flexible metal wire protection tubes should be used for wire protection tubes in humid places and directly buried underground; thin-walled steel tubes or flexible metal wire protection tubes should be used for wire protection tubes in dry places.
2.2.2 The inner and outer walls of the steel pipe should be treated with anti-corrosion. When buried in concrete, the outer wall of the steel pipe does not need to be treated with anti-corrosion; the outer wall of the steel pipe directly buried in the soil layer should be coated with two layers of asphalt, and when galvanized steel pipes are used, the zinc layer should be coated with anti-corrosion paint at the peeling place. When there are special requirements for the design, anti-corrosion treatment should be carried out according to the design regulations.
2.2.3 The steel pipe should not be flattened or cracked, and there should be no iron filings or burrs inside the pipe. The cut end should be flat and the pipe mouth should be smooth.
2.2.4 The connection of the steel pipe should meet the following requirements: 2.2.4.1 When threaded connection is adopted, the thread length of the pipe end should not be less than 1/2 of the length of the pipe joint; after connection, the thread should be exposed for 2 to 3 turns. The thread surface should be smooth and free of defects.
2.2.4.2 When the sleeve is connected, the sleeve length should be 1.5 to 3 times the outer diameter of the pipe, and the joints between the pipes should be located at the center of the sleeve. When the sleeve is connected by welding, the weld should be firm and tight. When the set screw is used for connection, the screw should be tightened. In a vibrating place, the set screw should have anti-loosening measures.
2.2.4.3 Galvanized steel pipes and thin-walled steel pipes should be connected by threaded connection or sleeve set screw connection, and should not be connected by fusion welding.
2.2.4.4 The inner surface of the steel pipe joint should be flat and smooth. 2.2.5 The connection between the steel pipe and the box (box) or equipment shall meet the following requirements: 2.2.5.1 The connection between the concealed black steel pipe and the box (box) can be welded, and the pipe mouth should be 3 to 5 mm higher than the inner wall of the box (box), and anti-corrosion paint should be applied after welding; the connection between the exposed steel pipe or concealed galvanized steel pipe and the box (box) should be fixed with a locking nut or a retaining ring cap, and the thread of the pipe end fixed with a locking nut should expose 2 to 3 buckles of the locking nut. 2.2.5.2 When the steel pipe is directly connected to the equipment, the steel pipe should be laid in the junction box of the equipment.
When the steel pipe is indirectly connected to the equipment, for indoor dry places, the end of the steel pipe should be equipped with a wire protection hose or a metal wire protection tube before being introduced into the equipment's junction box, and the steel pipe mouth should be tightly wrapped. For outdoor or indoor humid places, a waterproof elbow should be added to the end of the steel pipe, and the wire should be covered with a protective hose, and then introduced into the equipment's junction box after being bent into a dripping arc.
200mm.
The distance between the steel pipe mouth connected to the equipment and the ground should be greater than 2.2.6 The grounding connection of the steel pipe should meet the following requirements: 2.2.6.1 When the black steel pipe is threaded, the two ends of the connection should be welded with a jumper grounding wire or a special grounding wire clamp should be used for jumper connection. 2.2.6.2 The jumper grounding wire of the galvanized steel pipe or the flexible metal wire protection tube should be jumped with a special grounding wire clamp, and should not be connected by fusion welding. 2.2.7 A junction box should be set up at the location where the electrical appliances are installed. 2.2.8 Exposed steel pipes should be arranged neatly, the spacing between fixing points should be uniform, and the maximum distance between steel pipe clamps should comply with the requirements of Table 2.2.8; the distance between the clamps and the terminal, the midpoint of the elbow, the edge of the electrical appliance or box should be 150 to 500 mm. Engineering Construction Standard Full Text Information System
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Laying Method
Hanger, Bracket
Or Laying Along the Wall
Steel Pipe Type
Thick Wall Steel Pipe
Thin Wall Steel Pipe
Maximum Distance Between Steel Pipe Clamps
Steel Pipe Diameter (mm)
Maximum Distance Between Clamps (m)
2.3 Laying of Metal Hose
Above 65
2.3.1 Metal hose or flexible metal wire protection tube should be used for wire protection tube between steel pipe and electrical equipment and appliances, and the length of metal hose should not be greater than 2m. 2.3.2 Metal hose should be laid in a dry place that is not easily damaged by machinery, and should not be buried directly underground or in concrete. When using metal hoses in special places such as humid places, liquid-proof metal hoses with non-metallic sheaths and matching connectors should be used, and the sheaths should be flame-retardant.
2.3.3 Metal hoses should not be untwisted or loose, and there should be no joints in the middle. When connected to equipment and appliances, special joints should be used, and the connections should be reliably sealed; the connections of liquid-proof metal hoses should be well sealed.
2.3.4 The installation of metal hoses should meet the following requirements: 2.3.4.1 The bending radius should not be less than 6 times the outer diameter of the hose. 2.3.4.2 The spacing between fixed points should not be greater than 1m, and the distance between the pipe clamp and the terminal and the midpoint of the elbow should be 300mm.
2.3.4.3 For metal hoses connected to embedded lamps or similar appliances, the fixed pipe clamps at the end should be installed 1m along the length of the hose from the edge of the lamp or appliance. 2.3.5 Metal hoses should be reliably grounded and should not be used as grounding conductors for electrical equipment. 2.4 Laying of plastic pipes
2.4.1 Plastic pipes and their accessories used to protect wires must be made of flame-retardant materials. The outer wall of the plastic pipe should have continuous flame-retardant marks and manufacturer's marks with a spacing of no more than 1m. 2.4.2 Plastic pipes should not be laid in places with high temperatures or susceptible to mechanical damage. 2.4.3 The mouth of the plastic pipe should be flat and smooth; pipes and pipes, pipes and boxes (boxes) and other devices should be connected by insertion method. The joint surface should be coated with special adhesive, the interface should be firmly sealed, and should meet the following requirements:
2.4.3.1 When the pipes are connected by sleeves, the length of the sleeve should be 1.5 to 3 times the outer diameter of the pipe; the joint of the pipes should be located at the center of the sleeve. 2.4.3.2 When the pipe is connected to the device, the insertion depth should be 1.1 to 1.8 times the outer diameter of the pipe.
2.4.4 When hard plastic pipes are laid along the surface of buildings and structures, temperature compensation devices should be installed according to the design requirements.
2.4.5 When exposed hard plastic pipes pass through the floor slab where they are susceptible to mechanical damage, steel pipes should be used for protection, and the protection height should not be less than 500mm from the floor slab surface. 2.4.6 For hard plastic pipes directly buried underground or in the floor slab, protective measures should be taken in the section exposed to the ground where they are susceptible to mechanical damage.
2.4.7 When plastic pipes are directly buried in cast-in-place concrete, measures should be taken to prevent mechanical damage to the plastic pipes during concrete pouring.
2.4.8 The laying, installation and bending of plastic pipes and their accessories should be carried out at the allowable ambient temperature specified for the raw materials, and the temperature should not be lower than -15°C. 2.4.9 When laying plastic pipes in a groove on a brick wall, cement mortar with a strength grade not less than M10 should be used for surface protection, and the thickness of the protective layer should not be less than 15mm. 2.4.10 Exposed rigid plastic pipes should be arranged neatly, the spacing between fixing points should be evenly spaced, and the maximum distance between pipe clamps should comply with the provisions of Table 2.4.10. The distance between pipe clamps and terminals, turning midpoints, electrical appliances or box edges is 150-500mm. Maximum distance between rigid plastic pipe clamps (m)
Laying method
Hanger, bracket or laying along the wall
Table 2.4.10
Inner diameter of pipe (mm)
20 and below
150 and above
2.4.11 When laying semi-rigid plastic pipes or corrugated pipes, it is advisable to reduce bending. When the length of the straight section exceeds 15m or there are more than three right-angle bends, a junction box should be added. Engineering Construction Standard Full Text Information System
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3 Wiring
3.1 General Provisions
3.1.1 The model and specifications of the wires used for wiring shall comply with the design requirements. When there are no provisions in the design, the minimum cross-section of the wire core of the wires in different laying methods shall comply with the provisions of Appendix B of this code.
3.1.2 The layout of the wiring shall comply with the design requirements. When there are no provisions in the design, the minimum distance between outdoor insulated wires and buildings and structures shall comply with the requirements of Appendix C of this code, the minimum distance between indoor and outdoor insulated wires shall comply with the requirements of Appendix D of this code, and the minimum distance between indoor and outdoor insulated wires and the ground shall comply with the requirements of Appendix E of this code.
3.1.3 The connection of the wires shall comply with the following requirements: 3.1.3.1 When there are no special provisions in the design, the core wires of the wires shall be connected by welding, pressure plate crimping or sleeve connection. bzxz.net
3.1.3.2 The connection between the conductor and the equipment and apparatus shall meet the following requirements: (1) Single-strand copper core wire and single-strand aluminum core wire with a cross-section of 10mm2 or less can be directly connected to the terminals of the equipment and apparatus;
(2) The core of the multi-strand copper core wire with a cross-section of 2.5mm2 or less should be tightened with sugar tin or crimped before connecting to the terminals of the equipment and apparatus; (3) The terminals of the multi-strand aluminum core wire and the multi-strand copper core wire with a cross-section greater than 2.5mm2, except for the plug-in terminals provided by the equipment, should be welded or crimped before connecting to the terminals of the equipment and apparatus.
3.1.3.3 The welds of fusion welding connections shall not have defects such as depressions, slag inclusions, broken strands, cracks, and unwelded roots. The external dimensions of the welds shall comply with the provisions of the welding procedure qualification documents, and residual flux and welding slag shall be removed after welding.
3.1.3.4 The weld of the soldering connection should be full and smooth; the flux should be non-corrosive. The residual flux should be removed after welding.
3.1.3.5 The pressure plate or other special clamps should match the specifications of the wire core; the fasteners should be tightened in place, and the anti-loosening devices should be complete. 3.1.3.6 The sleeve connector and the pressing die should match the specifications of the wire core; when crimping, the crimping depth, number of crimping ports and crimping length should comply with the relevant provisions of the product technical documents.
3.1.3.7 When opening the insulation layer of the wire, the core wire should not be damaged. After the core wire is connected, the insulation tape should be wrapped evenly and tightly, and its insulation strength should not be lower than the insulation strength of the original insulation layer of the wire; the gap between the root of the terminal and the insulation layer of the wire should be tightly wrapped with insulation tape.
3.1.3.8 At the connection of the branch line of the wiring, the main line should not be subjected to the lateral tension of the branch line.
3.1.4 When porcelain clips, porcelain columns, porcelain bottles, plastic sheathed wires and trough plate wiring pass through walls or partitions, they should be protected by flame-retardant protective tubes. When passing through the floor slab, they should be protected by steel pipes. The distance between the protective height and the floor should not be less than 1.8m, but at the location where the switch is installed, it can be the same as the switch height.
3.1.5 The insulated wire with a rated voltage of not less than 500V should be used for the section of the household line entering the wall. The outer side of the wall-penetrating protective tube should have a waterproof elbow, and the wire should be bent into a dripping arc before it can be introduced into the room.
3.1.6 The insulated wire leading from the junction box to the appliance in the ceiling should be protected by a flexible metal wire protection tube or metal hose, and the wire should not have exposed parts. 3.1.7 The ambient temperature at the location where plastic insulated wires and plastic troughs are laid should not be lower than -15°C.
The horizontal and vertical allowable deviations of exposed wiring should comply with the provisions of Table 3.1.8. 3.1.9
When wiring uses multi-phase wires, the colors of the phase wires should be easily distinguished, and the colors of the phase wires and the neutral wires should be different. The colors of the wires in the same building or structure should be unified: the protective ground wire (PE wire) should use an insulated wire with alternating yellow and green colors; the neutral wire should use a light blue insulated wire.
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