This specification applies to the construction and acceptance of electrical installation projects in which explosive mixtures of gases, steam, dust, fibers and fire-hazardous substances are present or may be present during production, processing, handling, transportation or storage. GB 50257-1996 Electrical Installation Engineering Construction and Acceptance Specification for Electrical Installations in Explosive and Fire Hazardous Environments GB50257-1996 Standard download decompression password: www.bzxz.net

Engineering Construction Standard Full-text Information System
National Standard of the People's Republic of China
GB50257—96
Electrical Equipment Installation Engineering Explosion
And Fire Hazardous Environment
Code for Construction and Acceptance of Electric Device for Explosion Atmospheres and Fire Hazard Electrical Equipment Installation EngineeringConstruction Standard
1996—06—05Release
State Bureau of Technical Supervision
Ministry of Construction of the People's Republic of China
Engineering Construction Standard Full-text Information System
1996-12-01Implementation
Jointly Issued
Engineering Construction Standard Full-text Information System
National Standard of the People's Republic of China
Electrical Equipment Installation Engineering Explosion and Fire Hazardous Environment Electrical Equipment Construction and Acceptance Code
Code for Construction and Acceptance of Electric Device for Explosion Atmospheres and Fire Hazard Electrical Equipment Installation engineeringGB50257—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: December 1, 1996
Engineering construction standard full-text information system
Engineering construction standard full-text information system
Notice on the release of four national standards including "Specifications for Construction and Acceptance of Low-voltage Electrical Equipment for Electrical Installation Engineering"Jianbiao [1996] No. 337
According to the requirements of the State Planning Commission's document [19862630] and the Ministry of Construction's document (91) Jianbiaoji No. 6, the four standards including "Specifications for Construction and Acceptance of Low-voltage Electrical Equipment 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 Specification for Low Voltage Electrical Equipment for Electrical Installation Engineering" GB50254-96, "Construction and Acceptance Specification for Power Converter Equipment for Electrical Installation Engineering" GB50255-96, "Construction and Acceptance Specification for Crane Electrical Equipment for Electrical Installation Engineering" GB50256-96 and "Construction and Acceptance Specification for Electrical Equipment for Explosion and Fire Hazardous Environments for Electrical Installation Engineering" GB50257-96 are now approved as mandatory national standards, which will be implemented from December 1, 1996. The seventh chapter "Low Voltage Electrical Equipment", the sixth chapter "Silicon Rectifier Devices", the eighth chapter "Crane Electrical Equipment" and the sixteenth chapter "Electrical Equipment for Explosion and Fire Hazardous Areas" of the original "Construction and Acceptance Specification for Electrical Installation Engineering" GBJ232-82 are abolished at the same time. The Ministry of Electric Power Industry is responsible for the management of this specification, the Ministry of Electric Power Construction Research Institute is responsible for the specific interpretation, and the Ministry of Construction Standards and Quotas Research Institute is responsible for the publication and distribution. Ministry of Construction of the People's Republic of China
June 5, 1996
Engineering Construction Standards Full Text Information System
Engineering Construction Standards Full Text Information System
Installation of explosion-proof electrical equipment
General provisions
2.2 Installation of flameproof electrical equipment
2.3 Installation of increased safety and spark-free electrical equipment2.4 Installation of positive pressure electrical equipment...
2.5 Installation of oil-filled electrical equipment
2.6 Installation of intrinsically safe electrical equipment
2.7 Installation of dust explosion-proof electrical equipment
Electrical circuits in explosive atmospheres
General provisions
+00000660600
Cable circuits in explosive atmospheres
Steel pipe wiring in explosive atmospheres
Circuit lines of intrinsically safe electrical equipment and associated electrical equipment3 .4
Electrical installations in fire hazardous environments
4.1 Installation of electrical equipment
4.2 Electrical circuits
5.1 Protective grounding
5.2 Anti-static grounding
6 Project acceptance and acceptance
*(12)
(15)
(18)
(18)
…(20)
Appendix A Electrical clearance and creepage distance between exposed live parts of explosion-proof electrical equipment and between them and the metal casing
Additional instructions
Engineering Construction Standards Full-text Information System
Engineering Construction Standards Full-text Information System
1 General provisions
1.0.1 This specification is formulated to ensure the construction and installation quality of electrical installations in explosion and fire hazardous environments, promote the advancement of construction and installation technology, and ensure the safe operation of equipment and the safety of life and property of the state and the people.
1.0.2This specification applies to the construction and acceptance of electrical installation projects in environments where explosive mixtures of gas, steam, dust, fibers and fire-hazardous substances occur or may occur during production, processing, handling, transportation or storage. This specification does not apply to the following environments:
1.0.2.1 Underground mines.
Environments where explosive substances such as gunpowder, explosives and detonators are manufactured, used and stored.
Electrical installation areas such as electrolysis and electroplating that use electrical energy for production and are directly related to the production process.
1.0.2.4 Environments where strong oxidants are used and substances that can ignite on their own without external ignition sources.
Battery room.
1.0.2.6 Water, land and air transportation vehicles and offshore oil and gas well platforms. 1.0.3The installation of electrical installations in explosive and fire-hazardous environments shall be constructed in accordance with the approved design.
1.0.4 The transportation and storage of equipment and instruments shall comply with the relevant national regulations on the transportation and storage of materials. When the product has special requirements, it shall also comply with the requirements of the current product standards. 1.0.5 The equipment and instruments used shall comply with the provisions of the current national technical standards and shall have qualification certificates. The equipment shall have a nameplate, and explosion-proof electrical equipment shall have an explosion-proof mark. 1.0.6 After the equipment and instruments arrive at the site, the following acceptance inspections shall be carried out in a timely manner: 1.0.6.1 The packaging and sealing shall be in good condition.
Engineering Construction Standard Full Text Information System
Engineering Construction Standard Full Text Information System
Unpacking inspection and inventory, its model, specification and explosion-proof mark shall comply with the design requirements, and the accessories, accessories and spare parts shall be intact and complete. 1.0.6.3 The technical documents of the product shall be complete. 1.0.6.4 The nameplate of the explosion-proof electrical equipment must be marked with the "explosion-proof certificate number" issued by the national inspection unit.
1.0.6.5 Carry out an appearance inspection in accordance with the requirements of this specification. 1.0.7 Safety and technical measures during construction shall comply with the provisions of this specification and the current relevant safety and technical standards and technical documents of the product. In expansion and reconstruction projects, the safety regulations related to construction in the production plant's safety production (operation) regulations must be observed. For important processes, special safety and technical measures must be formulated in advance.
1.0.8 The construction of building projects related to the installation of electrical equipment in explosive and fire hazardous environments shall comply with the following requirements:
1.0.8.1 The engineering quality of buildings and structures related to the installation of electrical equipment in explosive and fire hazardous environments shall comply with the relevant provisions of the current national construction and acceptance specifications for building projects. When there are special requirements for design and equipment, they shall also meet their requirements. 1.0.8.2 Before the equipment is installed, the construction project should meet the following conditions (1) The foundation and frame should meet the design requirements and should reach the strength required for installation; (2) The indoor ground base should be completed and the ground elevation should be marked on the wall; (3) The embedded parts and reserved holes should meet the design requirements, the embedded electrical pipelines should not be missed or blocked, and the embedded parts should be firm; (4) The plastering and decoration works that may damage or seriously pollute the electrical equipment should be completed; (5) The templates and construction facilities should be removed and the site should be cleaned; (6) The doors and windows should be installed.
1.0.8.3 After the installation of electrical equipment in explosive and fire hazardous environments is completed and before it is put into operation, the building installation project shall meet the following requirements: (1) Defect repair and decoration work shall be completed; (2) Secondary grouting and plastering work shall be completed; (3) The explosion-proof ventilation system shall meet the design requirements and operate properly; Engineering Construction Standard Full Text Information System
Engineering Construction Standard Full Text Information System
(4) The works that cannot be carried out after power is supplied and affect the safety of operation shall be completed and accepted;
(5) The building lighting shall be delivered for use.
Except for anchor bolts, the fasteners used for equipment installation shall be galvanized products. 1.0.10 The zoning of explosive gas environment, explosive dust environment and fire hazardous environment shall comply with the relevant provisions of the current national standard "Design Code for Electrical Equipment in Explosive and Fire Hazardous Environments".
In addition to the provisions of this code, the construction and acceptance of electrical equipment in explosive and fire hazardous environments shall also comply with the provisions of the current relevant national standards and specifications. Engineering Construction Standard Full Text Information System
Engineering Construction Standard Full Text Information System
Installation of Explosion-proof Electrical Equipment
2.1 General Provisions
2.1.1 The type, level, group, environmental conditions and special markings of explosion-proof electrical equipment shall comply with the design requirements.
2.1.2 Explosion-proof electrical equipment shall have an "EX" mark and a nameplate indicating the type, level and group of explosion-proof electrical equipment, and the nameplate shall indicate the explosion-proof certificate number issued by the national designated inspection unit.
2.1.3 Explosion-proof electrical equipment should be installed on a metal bracket. The bracket should be firm, and the fixing bolts of electrical equipment with vibration should have anti-loosening devices. 2.1.4 After the internal wiring of the junction box of explosion-proof electrical equipment is tightened, the electrical clearance and creepage distance between the exposed live parts and between the metal casing shall not be less than the provisions of Appendix A. 2.1.5 The inlet of explosion-proof electrical equipment and cables and wires should be able to be reliably wired and sealed. The elastic sealing pads and metal gaskets of the redundant inlet should be complete, and the compression nut should be tightened to seal the inlet. The thickness of the metal gasket shall not be less than 2mm. 2.1.6 The maximum temperature of the surface of the shell of explosion-proof electrical equipment (increased safety type and spark-free type including the inside of the equipment) shall not exceed the provisions of Table 2.1.6. The maximum temperature of the surface of the shell of explosion-proof electrical equipment Temperature group
Maximum temperature (℃)
Note: The temperature groups of T1~T6 in the table shall comply with the relevant provisions of the current national standard "General Requirements for Explosion-proof Electrical Equipment for Explosive Environments". This standard divides the explosive gas mixture into six groups according to the ignition temperature. The temperature groups of electrical equipment and the grouping of gases are rubber-adapted. Engineering 4 Construction Standard Full Text Information SystemWww.bzxZ.net
Engineering Construction Standard Full Text Information System
2.1.7 Transparent parts or other parts made of plastic shall not be scrubbed with solvents, but can be scrubbed with household detergents.
2.1.8 The button of the emergency exhaust fan shall be installed separately in a convenient position for operation and shall be marked with special signs.
2.1.9 The installation of lamps shall meet the following requirements: 2.1.9.1 The type, model and power of the lamps shall meet the requirements of the design and product technical conditions and shall not be changed at will.
2.1.9.2 The spiral bulbs shall be tightened, have good contact and shall not be loose. 2.1.9.3
The outer cover of the lamp shall be complete and the bolts shall be tightened. 2.2 Installation of flameproof electrical equipment
2.2.1 Before installing flameproof electrical equipment, the following inspections shall be carried out: 1 The model and specifications of the equipment shall meet the design requirements; the nameplate and explosion-proof mark shall be correct and clear.
The outer shell of the equipment shall be free of cracks and damage.
3 The flameproof structure and gap shall meet the requirements.
1 The fastening bolts of the joint surface should be complete, and the anti-loosening facilities such as spring washers should be complete and intact, and the spring washers should be flattened.
The sealing gaskets should be complete and intact, without aging and deformation, and meet the technical requirements of the product.
The transparent parts should be smooth and undamaged.
The moving parts should be free of collision and friction.
3 The terminal board and insulating parts should not be broken, the terminal box cover should be tightened, and the electrical clearance and creepage distance should meet the requirements.
The grounding mark and grounding screw should be intact.
2.2.2 Flameproof electrical equipment should not be disassembled. When disassembly and assembly are required, the following requirements should be met: 2.2.2.1 The flameproof surface should be properly protected and not damaged. 2 There should be no sand holes or mechanical scars on the flameproof surface. 2.2.2.2
3 Explosion-proof surfaces without electroplating or phosphating layer shall be coated with phosphating paste, electric 2.2.2.3
Engineering Construction Standard Full Text Information System
Engineering Construction Standard Full Text Information System
compound grease or No. 204 anti-rust oil after cleaning. Painting is strictly prohibited. 2.2.2.4 There shall be no rust layer on the explosion-proof surface during assembly. 2.2.2.5 The fastening bolts of the explosion-proof joint surface shall not be replaced arbitrarily, and the spring washers shall be complete.
For threaded explosion-proof structures, the minimum number of engagement threads and the minimum engagement depth shall not be less than the provisions of Table 2.2.2.
Minimum number of engagement threads and minimum engagement depth of threaded explosion-proof structures Net volume of shell V
V≤100
1001.5
Requirements.
Transparent parts should be smooth and free of damage.
Moving parts should be free of collision and friction.
3The terminal board and insulating parts should not be broken, the terminal box cover should be tightened, and the electrical clearance 2.2.1.8
and creepage distance should meet the requirements.
The grounding mark and grounding screw should be intact.
2.2.2 Flameproof electrical equipment should not be disassembled. When disassembly is required, the following requirements should be met: 2.2.2.1 The flameproof surface should be properly protected and not damaged. 2 There should be no sand holes or mechanical scratches on the flameproof surface. 2.2.2.2
3 Explosion-proof surfaces without electroplating or phosphating layer shall be coated with phosphating paste, electric 2.2.2.3
Engineering Construction Standard Full Text Information System
Engineering Construction Standard Full Text Information System
compound grease or No. 204 anti-rust oil after cleaning. Painting is strictly prohibited. 2.2.2.4 There shall be no rust layer on the explosion-proof surface during assembly. 2.2.2.5 The fastening bolts of the explosion-proof joint surface shall not be replaced arbitrarily, and the spring washers shall be complete.
For threaded explosion-proof structures, the minimum number of engagement threads and the minimum engagement depth shall not be less than the provisions of Table 2.2.2.
Minimum number of engagement threads and minimum engagement depth of threaded explosion-proof structures Net volume of shell V
V≤100
1001.5
Requirements.
Transparent parts should be smooth and free of damage.
Moving parts should be free of collision and friction.
3The terminal board and insulating parts should not be broken, the terminal box cover should be tightened, and the electrical clearance 2.2.1.8
and creepage distance should meet the requirements.
The grounding mark and grounding screw should be intact.
2.2.2 Flameproof electrical equipment should not be disassembled. When disassembly is required, the following requirements should be met: 2.2.2.1 The flameproof surface should be properly protected and not damaged. 2 There should be no sand holes or mechanical scratches on the flameproof surface. 2.2.2.2
3 Explosion-proof surfaces without electroplating or phosphating layer shall be coated with phosphating paste, electric 2.2.2.3
Engineering Construction Standard Full Text Information System
Engineering Construction Standard Full Text Information System
compound grease or No. 204 anti-rust oil after cleaning. Painting is strictly prohibited. 2.2.2.4 There shall be no rust layer on the explosion-proof surface during assembly. 2.2.2.5 The fastening bolts of the explosion-proof joint surface shall not be replaced arbitrarily, and the spring washers shall be complete.
For threaded explosion-proof structures, the minimum number of engagement threads and the minimum engagement depth shall not be less than the provisions of Table 2.2.2.
Minimum number of engagement threads and minimum engagement depth of threaded explosion-proof structures Net volume of shell V
V≤100
1002000
Minimum thread engagement depth
Minimum thread engagement number
IA, IB
2
times of the test safety number but at least 6
Note: The classification of IAIB and IC in the table shall comply with the relevant provisions of the current national standard "General Requirements for Explosion-proof Electrical Equipment for Explosive Environments". The explosive gas mixture shall be divided into Class I (factory electrical equipment) into three levels: A, B, and C according to its maximum test safety gap or minimum ignition current ratio. 2.2.3
There shall be no friction between the shaft and the shaft hole of the flameproof motor, and between the fan and the end shield under normal working conditions.
2.2.4The electrical interlocking device of flameproof electrical equipment that generates sparks or arcs during normal operation must be reliable. The shell cover should not be opened when the power is on, and the power should not be turned on after the shell cover is opened. The shell fastened with bolts should be checked for the "open cover after power off" warning sign and should be intact. 2.2.5 The inspection and installation of flameproof plugs shall meet the following requirements: 2.2.5.1 When the plug is inserted, the grounding or neutral contact shall be connected first; when the plug is pulled out, the main contact shall be disconnected first.
2.2.5.2 The switch shall be closed only after the plug is inserted. When the switch is in the disconnected position, the plug shall be inserted or pulled out.
2.2.5.3 The slow-motion device to prevent sudden pull-out shall be intact and reliable and shall not be loose. Engineering and Construction Standards Full Text Information System
Engineering Construction Standards Full Text Information System
2.3 Installation of Increased Safety and Spark-free Electrical Equipment 2.3.1 Before installing increased safety and spark-free electrical equipment, the following inspections shall be carried out: the model and specifications of the equipment shall meet the design requirements; the nameplate and explosion-proof mark shall be correct and clear.
The cover shall be tightened.
The housing and light-transmitting parts of the equipment should be free of cracks and damage. The fastening bolts of the equipment should have anti-loosening measures to prevent loosening and rust. The terminal box protection device and accessories should be complete and intact. 2 The single-sided air gap between the stator 2.3.2
and the rotor of the increased safety motor and spark-free motor with sliding bearings should be measured. The air gap value shall not be less than 1.5 times the value specified in Table 2.3.2; the single-sided air gap between the stator and the rotor of the increased safety motor with rolling bearings equipped with a gap measuring hole shall be measured. The air gap value shall not be less than the value specified in Table 2.3.2. The minimum single-sided air gap between the stator and rotor of the increased safety and spark-free motors with rolling bearings is 8 (mm) Number of poles
6 and above
D≤75
Note: @D is the rotor diameter,
0.25+(D-75)/300
0.2+(D-75)/500
0.2+(D-75)/800
② The single-sided air gap of the pole-changing motor is calculated based on the minimum number of poles; Table 2.3.2
If the core length L exceeds 1.75 times the diameter D, the air gap value is calculated by multiplying the value in the above table by L/1.75D; the radial air gap value needs to be measured when the motor is stationary. 2.4 Installation of positive pressure electrical equipment
1 Before installing positive pressure electrical equipment, the following inspections shall be carried out: 2.4.1
1 The model and specifications of the equipment shall meet the design requirements; the nameplate and explosion-proof mark shall be correct and clear.
Engineering Construction Standard Full Text Information System
Engineering Construction Standard Full Text Information System
The shell and light-transmitting parts of the equipment shall be free of cracks and damage. 3 The fastening bolts of the equipment shall have anti-loosening measures, without looseness and rust, and the junction box cover shall be tightened.
Protective devices and accessories shall be complete and intact. 2.4.1.5 The sealing gaskets shall be complete and intact, without aging and deformation, and shall meet the requirements of product technical conditions.
2.4.2 The air or gas entering the ventilation, inflation system and electrical equipment shall be clean and shall not contain explosive mixtures and other harmful substances. 2.4.3 The gas discharged during the ventilation process should not be discharged into an explosive hazardous environment. When discharged into an explosive gas environment zone 2, effective measures must be taken to prevent sparks and hot particles from being blown out of the electrical equipment and its ventilation system.
2.4.4 The electrical interlocking device of the ventilation and inflation system should operate normally according to the procedure of ventilation first and then power supply, and power off first and then wind off. Before the electrical equipment is powered on and started, the volume of the protective gas in the shell shall not be less than the sum of the minimum ventilation volume specified in the product technical conditions and 5 times the volume of the connected pipes.
2.4.5 The micro-pressure relay shall be installed at the outlet of the lowest point of wind pressure and air pressure. The wind pressure and air pressure values ​​in the electrical equipment and ventilation and inflation systems during operation shall not be lower than the minimum required pressure value specified in the product technical conditions. When it is lower than the specified value, the micro-pressure relay shall operate reliably and shall meet the following requirements:
2.4.5.1 When the explosive gas environment is zone 1, it shall be able to reliably cut off the power supply. 2.4.5.2
When the explosive gas environment is Zone 2, the warning signal should be able to be issued reliably.
3 Sparks and arcs inside the positive pressure electrical equipment in operation should not be blown out from the gaps or 2.4.6
air outlets.
2.4.7 The ventilation duct should be well sealed.
2.5 Installation of oil-filled electrical equipment
2.5.1 Before installing oil-filled electrical equipment, the following inspections should be carried out: 2.5.1.1 The model and specifications of the equipment should meet the design requirements; the nameplate and explosion-proof mark should meet the engineering construction standard full text information system
Tip: This standard content only shows part of the intercepted content of the complete standard. If you need the complete standard, please go to the top to download the complete standard document for free.