Shenzhen Zhongnuo Testing Technology Co., Ltd. is based in South China, offering on-site explosion-proof construction, safety inspections, renovations, project acceptance, and explosion-proof installation consulting services. We are well-versed in explosion-proof construction standards, boasting experienced construction teams and a wealth of practical experience. We have served major corporations such as PetroChina, LG, Hanlan Environment, BOE Technology Group, and Sinovac Biotech, receiving consistent praise and trust from our clients!
Installation of electrical wiring in explosive environment should comply with the following regulations (Shared by Shenzhen ZhongNuo Inspection Technology Co., Ltd.)
Electrical wiring should be installed in environments with low explosion hazards or far from release sources, and should comply with the following regulations:
1) When the weight of the material is heavier than air, electrical lines should be laid at a higher level or directly buried underground; for overhead installation, cable trays should be used; when laying in a cable trench, the trench should be filled with sand, and drainage measures should be installed.
2) Electrical wiring should be laid outside the walls of buildings or structures where explosive hazards are present.
3) In explosive dust environments, cables should be laid in locations where dust does not accumulate easily and is easy to remove.
(2) Holes in walls or floors at different areas traversed by electrical line trenches, cable trays, or conduits should be tightly sealed with non-combustible materials.
(3) When laying electrical lines, it is advisable to avoid areas susceptible to mechanical damage, vibration, corrosion, ultraviolet radiation, and potential overheating. If unavoidable, preventive measures should be taken.
(4) Wiring with steel pipes can use insulated single-core or multi-core conductors without sheathing. When the steel pipe contains three or more conductors, the total cross-sectional area of the conductors, including the insulation, should not exceed 40% of the steel pipe's cross-sectional area. Steel pipes should be used for low-pressure fluid transmission, with lock zinc焊接. The threaded portion of the steel pipe connections should be coated with lead oil or phosphating paste. Condensation water should be excluded at points where condensation may occur, and sealed joints should be installed on the pipeline.
(5) Electrical wiring for steel pipe installations in explosive gas environments should be properly insulated and sealed, and should comply with the following regulations:
1) During normal operation, all ignition source enclosures within a 450mm radius should be sealed off.
2) Steel pipes with a diameter of 50mm or more should be isolated and sealed within 450mm of the incoming junction box.
3) Isolation and sealing should be conducted between adjacent explosive environments, as well as between explosive environments and adjacent other hazardous or non-hazardous environments. During sealing, the inner part of the seal should be filled with a fibrous layer as the bottom or separator layer. The effective thickness of the filling layer should not be less than the inner diameter of the steel pipe, and it must not be less than 16mm.
4) Components for isolation sealing should not be used for wire connections or branching.
(6) Intermediate joints are strictly prohibited on cable lines within Area 1, and intermediate joints should not be present in Areas 2, 20, and 21.
(7) When terminating cables or wires, if the internal conductors are stranded, they should be connected using a crimped terminal or lug. Connections and terminations of aluminum-core insulated conductors or cables should be made by crimping, soldering, or brazing. When connecting to equipment (excluding lighting fixtures), a copper-aluminum transition connector should be used.
(8) Overhead power lines must not cross explosive gas environments. The horizontal distance between overhead lines and explosive gas environments should not be less than 1.1 times the height of the tower. In special cases, after taking effective measures, the distance may be appropriately reduced.

Basic Dust Explosion-proof Construction Standards
In facilities where explosive dust is present, such as flour mills, feed factories, grinding workshops, and plastic production plants, the requirement for explosion-proof measures on-site is particularly important. The installation and use of explosion-proof wiring, electrical equipment, dust removal systems, architectural layouts, and explosion-proof venting must all comply with the relevant dust explosion-proof standards. Based on a wealth of explosion-proof electrical construction and retrofitting cases, Shenzhen ZhongNuo Testing Technology Co., Ltd. has summarized the following points:
1. Structure and layout of the building
Process equipment with dust explosion hazards or buildings (structures) with combustible dust should be separated from other buildings (structures), and their fire protection distances should comply with the relevant provisions of GB50016.
(2) The building should be a single-story structure, and the roof should utilize lightweight construction.
(3) The structural requirements for multi-story buildings are as follows:
A. Multi-story buildings are best suited for frame structures.
B. Buildings without frame structures must be equipped with explosion relief openings in compliance with requirements.
C. If windows or other openings are used as explosion relief vents, they must be calculated and ensured to effectively vent during an explosion.
(4) The requirements for evacuation routes are as follows:
A. The work area should have an evacuation route, and the number and location of the evacuation routes should comply with the provisions of GB50016.
B. The door should open outward and no threshold should be installed.
C. Detailed road signs and emergency lighting should be set up for evacuation routes.
2. Process Equipment
(1) For process equipment with a dust explosion risk in the factory building, it is advisable to locate it at a higher level of the structure and close to the outer wall.
(2) Equipment with explosive hazards should be located in outdoor areas outside of buildings.
(3) Equipment or devices that come into direct contact with dust (such as light sources, heating sources, etc.) should have surface temperatures below the respective dust's low ignition temperature.
(4) In areas where combustible dust is present, the drive mechanisms of the equipment and installations shall comply with the following requirements:
The bearings of the process equipment should be dust-proof and sealed. If there is a possibility of overheating, a detector capable of continuously monitoring the bearing temperature should be installed.
B. Belt drive is not recommended. If belt drive is used, a speed difference sensor and an automatic anti-slip protection device should be installed. In case of sliding friction, the protection device should ensure automatic shutdown.
(5) At the feeding point of the process flow, a magnet, an air separator, or a sieve capable of removing impurities mixed with the material should be installed to prevent collision between impurities and equipment.
(6) Effective measures should be taken to prevent sparks from occurring when stainless steel is abraded against powders containing aluminum, zirconium, or other metals.
(7) In the event of an explosion, protective stopping should be achieved by installing several power supply control boxes that can interlock with each other, based on the size of the workshop. In emergency situations, the power supply to all motors should be able to be cut off promptly.
(8) All process equipment components such as joints, inspection doors, baffles, and explosion vent covers should be sealed tightly.
(9) The equipment housing should be made of non-flammable material
(10) The moving parts of the equipment should operate smoothly without any scraping, bumping, jamming, or rubbing.
(11) If the strength of the process equipment is insufficient to withstand the overpressure generated by internal dust explosion under its actual operating conditions, an explosion relief port should be installed, and the size of the relief port should comply with the relevant provisions of GB/T15605.
(12) The explosion relief port should be located near potential ignition sources, and it should be as high as possible, preferably at the top or upper part of the containment structure. It must not vent towards flammable and explosive hazard areas to prevent igniting others, and it must not vent towards public areas to avoid injury from the explosion relief.
3. Lightning and static electricity protection
Hazardous dust explosion areas should adopt corresponding lightning protection measures in accordance with the relevant provisions of GB50057. When static electricity hazards are present, the following regulations should be observed:
(1) All metal equipment, device enclosures, metal pipes, brackets, components, parts, etc., generally employ static-dissipative direct grounding. For those that are not convenient or not permitted by the process to be grounded directly, indirect grounding can be achieved through static-dissipative materials or products.
(2) Equipment directly used for containing electrostatic powder, such as conveyance pipes (belts) for the powder, should be made of metal or antistatic materials.
(3) All metal pipe connections should be bonded together.
(4) Operators should take anti-static precautions.
(5) Avoid using methods that involve direct grounding of metallic conductors or meshes in contact with high-speed flowing powders to dissipate static electricity.

As the world's energy and chemical industries develop, construction in explosive hazardous environments is becoming more widespread, and the prevention and acceptance of explosive environments are increasingly important.
Especially in flammable dust environments, such as plastic factories, feed/food/grain processing plants, metal polishing workshops, and papermaking/forestry wood flour/fiber dust factories, the number of projects involving explosion-proof installations, designs, and renovations is also increasing.
Whether it's large-scale explosion-proof or local explosion-proof, if there are hidden dangers in product quality or installation/renovation quality,
Our personnel and property safety are greatly threatened, so we must control the quality at every process to ensure the reliability and safety of explosion-proof installations and renovations.
Shenzhen ZhongNuo Testing Technology Co., Ltd. offers explosion-proof construction and modification consulting services, boasting rich qualifications and case studies. Worth it!

Shenzhen ZhongNuo Testing Technology Co., Ltd. offers explosion-proof construction services for hazardous areas involving explosive risks.
1. Explosion-proof site inspection and consultation
2. Explosion-proof engineering site construction and renovation
3. Explosion-proof construction acceptance
4. Explosion-proof electrical installation, maintenance, and renovation
5. Explosion relief walls, doors, and windows installation
6. Dust Removal Equipment Installation and Retrofitting Construction
Explosion-proof electrical retrofitting and on-site explosion-proof construction consulting services for hazardous areas — Shenzhen Zhongnuo Testing Technology Co., Ltd.