Shenzhen ZhongNuo Testing Technology Co., Ltd. offers on-site explosion-proof electrical inspection, explosion-proof project acceptance services, and consulting services. We also provide explosion-proof rectification and construction services for items not meeting inspection standards.
Shenzhen Zhongnuo Testing Technology Co., Ltd. summarizes the experience from previous explosion-proof electrical inspections, common non-conforming items found during on-site explosion-proof electrical inspections:
Currently, our country's hazardous chemical production enterprises frequently experience accidents, thus necessitating a high priority on safety production inspections. We should gradually clarify the safety performance of products and equipment involving personal safety, gradually forming a significant role in safety production inspections. Now, safety inspections can provide a lot of technical support to hazardous chemical enterprises, especially the electrical explosion-proof safety inspections, which should be widely promoted, continuously guiding and serving the enterprises in their safe production endeavors.
1. Improper design within the hazardous area
Many businesses are constrained by their company history, and at the same time, the production materials of the companies are continuously changing, making the demarcation of hazardous areas less orderly and rather chaotic. The layout of equipment and facilities does not meet the explosion-proof requirements.
2. Understanding of explosion-proof knowledge is relatively weak.
In many hazardous chemical enterprises, there is a lack of distinction between electrical explosion-proof safety inspections and fire prevention electrical and building electrical inspections. There are irregularities in areas such as temporary electrical use and firework operations, as well as in equipment replacement and electrical management systems.
3. Improper installation of explosion-proof electrical equipment
Although many companies now have explosion-proof features in their electrical facilities, there are still many issues with installation, such as direct wiring connection of main lines, missing explosion-proof face screws, and using PVC pipes for wiring in incoming and outgoing pipelines. Additionally, the installation of switches and outlets, wiring terminals, power and lighting distribution boxes, grounding systems, and electrical wiring systems is not very reasonable, with many safety concerns.
4. Explosion-proof electrical wiring routing does not meet requirements
In explosive environments, most companies currently do not place enough emphasis on explosion-proof electrical wiring, fail to correctly understand the technical parameters of hazardous materials in dangerous areas, and often wire arbitrarily.
5. Non-standard grounding of explosion-proof electrical equipment
For the grounding of explosion-proof electrical equipment, the main types include internal neutral grounding, housing protective grounding, and antistatic grounding. The grounding of uncharged metal housing is often poorly done, frequently resulting in the grounding wire being connected to the material pipeline.
6. Lacking overall planning for explosion-proof zones in the selection of power distribution rooms and control rooms.
Many power distribution and control rooms are located in explosion-proof zones without adequate measures in place.
7. Inadequate explosion-proof selection and requirements for explosion-proof electrical equipment
In electrical explosion-proof equipment, there is no distinction between environments with combustible dust and those with explosive gases; they are used interchangeably. In different hazardous areas, there are various electrical explosion-proof regulations, markings, and types, along with differing levels and temperature groups. However, many enterprises mix and match explosion-proof electrical equipment without distinguishing these differences.

The "Electrical Explosion Proof Inspection Report" issued from regular inspections of explosion-proof electrical equipment is based on standards including but not limited to:
GB 50058-2014 "Code for Design of Electrical Installations in Explosive Hazardous Environments"
GB50257-2014 Code for Construction and Acceptance of Electrical Installation in Explosive and Flammable Gas and Dust Environments
GB/T3836.15-2017 "Electrical Equipment for Explosive Gas Atmospheres - Part 15: Electrical Installations in Hazardous Areas (Excluding Coal Mines)"
AQ3009-2007 Electrical Explosion Protection Safety Standard for Hazardous Areas

Regulations and laws regarding regular inspections of explosion-proof electrical equipment:
Explosion-proof equipment used in hazardous areas must undergo a series of life cycle stages, including production, installation, operation, inspection, maintenance, and withdrawal from the market.
Regular inspections ensure the usage condition and explosion-proof safety performance. Corresponding regulations are also established by relevant laws and regulations in our country.
In the standard AQ3009-2007 "Electrical Safety and Explosion-proof Regulations for Hazardous Places," there are explicit provisions:
Regular inspections should be entrusted to safety production inspection agencies with explosion-proof qualifications, with intervals generally not exceeding 3 years.
The company should take corrective actions promptly based on the inspection results and file the inspection report and the rectification status with the safety production supervision and management department.
The preface of AQ3009-2007 "Electrical Safety and Explosion-Proof Regulations for Hazardous Areas" also explicitly states that Chapters 4, 5, 6, and 7 are mandatory and must be strictly enforced. Therefore, such safety regulations are part of the legal and regulatory framework and must be strictly enforced as mandatory!

After the explosion-proof project is completed, it requires a third-party institution with explosion-proof inspection qualifications (Shenzhen Zhongnu Inspection Technology Co., Ltd.) to conduct the project acceptance. Only after passing the acceptance can the project be put into use.
Examination Content for Explosion-Proof Engineering
1. The label of explosion-proof electrical equipment must include the explosion-proof qualification number issued by the inspection unit.
2. Types, levels, and groups of explosion-proof electrical equipment should comply with the design.
3. The housing of explosion-proof electrical equipment should be free of cracks and damage; the paint should be intact. The cover of the junction box should be securely fastened, and the fixing bolts and anti-loosening devices should be in place.
4. The ventilation and exhaust systems of positive pressure electrical equipment should be unobstructed, correctly connected, and the installation positions of the inlets and outlets meet the requirements.
5. Excess entry ports of electrical equipment should be sealed as per regulations.
6. The installation of sealed devices in electrical wiring should comply with regulations.
7. The wiring engineering for intrinsically safe electrical equipment shall comply with the design for the route and elevation of the lines; the lines should be marked with a sky blue sign.
8. Electrical installations must have proper grounding or neutral connection, and antistatic wiring, all in compliance with design specifications, ensuring stable and reliable grounding.
On-site Explosion-proof Electrical Equipment Regular Inspection Consultancy Services - Shenzhen ZhongNuo Testing Technology Co., Ltd.