Shenzhen Zhongnuo Inspection & Technology Co., Ltd. offers on-site explosion-proof electrical inspection, explosion-proof project acceptance services, and can provide explosion-proof rectification and construction services for items that do not meet the inspection standards.
Shenzhen ZhongNuo Testing Technology Co., Ltd. summarizes the experience from past explosion-proof electrical inspections and compiles the following common non-conforming items in on-site explosion-proof inspections for your reference.
Common phenomena include:
1. Corrosion and damage to explosion-proof enclosures. The protective enclosures of explosion-proof electrical equipment are damaged due to corrosion from surrounding media, leading to rust穿孔, structural degradation, and loss of original strength, rendering the explosion-proof electrical equipment ineffective in preventing explosions.
2. Explosion-proof protective casing subjected to electrochemical corrosion and damage. In situations such as electrical leakage or potential drift, the metallic casing becomes electrically charged. The charged metal in contact with the air medium acts like a battery, causing corrosion of the metallic casing. This leads to the loss of the electrical appliance's explosion-proof capability.
3. Damage due to external forces and mechanical impacts. This includes damage to the protective casing caused by collisions with other equipment or mechanical substances on the work site, as well as casing damage resulting from excessive force during installation.
4. Shell damage due to excessive temperature, caused by material shrinkage and deformation of the protective shell due to climate adaptation issues in cold regions, leading to shell cracking and subsequent damage to the protective shell.
5. Damage caused by improper installation. Damage, missing parts, and loss of protective functions resulting from non-compliance with installation requirements during the installation of explosion-proof electrical equipment.
6. Inadequate sealing, such as improper handling of sealing materials during installation and maintenance, loose fit of sealing surfaces, damaged sealing components, unsuitable or missing fasteners for sealing fixation, leads to inadequate or weak explosion-proof performance.
7. Quality issues with explosion-proof electrical equipment, including substandard material for the explosion-proof housing and an unreasonable structural design that fails to meet required load-bearing capacity; internal wiring is prone to loosening, and an impractical internal circuit can easily cause sparking or overheating; unreasonable mechanical structure components, excessive equipment temperature, and internal water accumulation may lead to malfunctions in explosion-proof electrical equipment.
8. Due to actual changes in hazardous areas caused by the alteration of production facilities, the electrical equipment in the area has not been promptly upgraded to explosion-proof equipment.
9. Incorrect selection of explosion-proof electrical equipment; intrinsic safety electrical equipment used with non-intrinsic safety voltage, and increased safety enclosures used for generating light, heat, and other circuit equipment.
As an end-user of explosion-proof electrical equipment, it is necessary to conduct regular explosion-proof inspections even in explosive hazardous areas where such equipment is installed and used. This is both a requirement of various departments and a high level of concern for personnel and property safety.

Shenzhen ZhongNuo Inspection Technology Co., Ltd. summarizes the experience from previous explosion-proof electrical inspections, common non-conformities found during on-site explosion-proof electrical inspections:
Currently, China's hazardous chemical production enterprises are prone to frequent accidents, thus demanding a high level of attention to safety production inspections. We should gradually clarify the safety performance of products and equipment involving personal safety, and step by step, establish their significant role in safety production inspections. Now, safety inspections can provide substantial technical support to hazardous chemical enterprises, especially the electrical explosion-proof safety inspections, which should be widely promoted, continually guiding and serving the enterprises' safety production efforts.
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 enterprises 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 no distinction made between electrical explosion-proof safety inspections, fire protection electrical inspections, and building electrical inspections. In areas such as temporary power use, hot work operations, equipment replacement, and electrical management systems, there is a lack of standardization.
3. Improper installation of explosion-proof electrical equipment
Although many companies now have explosion-proof functions in electrical facilities, there are still many issues in installation, such as direct wiring connections, missing explosion-proof face screws, and using PVC pipes for wiring in pipeline inlets and outlets. Additionally, the installation of switches and outlets, wiring terminals, power and lighting distribution boxes, grounding systems, and electrical wiring systems are 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 pay enough attention to explosion-proof electrical wiring, fail to correctly understand the technical parameters of hazardous materials in dangerous areas, and often install wiring arbitrarily.
5. Non-standard grounding of explosion-proof electrical equipment
For explosion-proof electrical equipment grounding, the main types include internal neutral grounding, case protective grounding, and antistatic grounding. Poor grounding of uncharged metallic casings is common, often resulting in grounding wires being connected to material pipelines.
6. Lacking an overall planning for explosion-proof zones in the selection of power distribution rooms and control rooms.
Many power distribution and control rooms are located within explosion-proof zones without adequate measures in place.
7. Inadequate explosion-proof selection and requirements for explosion-proof electrical equipment
In electrical explosion-proof facilities, there is no distinction between environments with combustible dust and those with explosive gases; they are used interchangeably. Different hazardous areas have varying electrical explosion-proof regulations, explosion-proof markings, and types, as well as different levels and temperature classes. However, many enterprises mix and match explosion-proof electrical equipment without distinguishing these differences.

What qualifications are required for regular inspection of explosion-proof electrical equipment?
The regular inspections of explosion-proof electrical equipment, as mentioned in the previous text and conducted according to the AQ 3009-2007 "Electrical Safety and Explosion-Proof Requirements for Hazardous Areas" standard, must be carried out by a testing center with explosion-proof professional qualifications. This qualification is authorized by the CNAS (China National Accreditation Service for Conformity Assessment) and can be verified on the CNAS website.

Regulations and laws regarding regular inspections of explosion-proof electrical equipment:
Explosion-proof equipment used in hazardous explosive areas throughout its entire lifecycle, including production, installation, use, inspection, maintenance, and withdrawal from the market,
Regular inspections provide a strong guarantee for the usage status and explosion-proof safety performance. Relevant regulations of our country also stipulate this accordingly.
There are explicit provisions in the standard AQ3009-2007 "Electrical Safety and Explosion Proof Regulations for Hazardous Areas":
Inspections should be conducted by safety production inspection agencies with explosion-proof qualifications at intervals not exceeding three 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 system, and mandatory compliance is required!
On-Site Explosion-Proof Electrical Equipment Regular Inspection Consulting Service - Shenzhen Zhongnuo Testing Technology Co., Ltd.