Shenzhen Zhongnuo Testing Technology Co., Ltd. is based in South China and specializes in explosion-proof certification and coal safety certification application consulting services, offering one-stop explosion-proof technology consulting services.
What is the relationship between the explosion-proof certificate and the explosion-proof CCC certification?
The explosion-proof certificate and explosion-proof 3C certification are for different types of explosion-proof products.
Explosion-proof 3C Certification is for products listed in the Explosion-proof 3C Catalog. There is a dedicated product catalog for Explosion-proof 3C. Products within the catalog must apply for Explosion-proof 3C Certification, which involves a "Product Testing + Factory Audit" approach, including both type tests for the products and on-site factory audits.
Certification for explosion-proof products outside the explosion-proof 3C catalog. The certification model is product testing; upon successful product testing, the explosion-proof certification can be issued frequently.
Of course, products outside the explosion-proof 3C catalog can also apply for explosion-proof certifications alone, but there's a risk of being penalized by market supervision. This is something for the client to consider on their own.

What do the 0, 1, and 2 zones in explosion-proof certification mean?
This is the division of explosion-proof areas in explosive gas environments, categorized into Zone 0, Zone 1, and Zone 2.
Zone 0: Areas where explosive gas mixtures are continuously present or exist for extended periods (over 1000 hours per year).
Zone 1: Areas where explosive gas mixtures may be present under normal conditions.
Zone 2: Under normal circumstances, explosive gas mixtures are unlikely to occur, only present in abnormal conditions for short periods (less than 10 hours per year).
Division of explosion-proof areas in explosive dust environments: Zones 20, 21, 22

Sample Requirements for Explosion-Proof Certification Application:
The sample machine submitted by the company should match the approved drawings and be fully assembled; the number of units inspected should meet the requirements.
If special disassembly tools are required, they should be sent along as well.
For encapsulated electrical equipment, a set of both encapsulated and non-encapsulated products should be submitted.
The transparent parts for the observation window should be sent separately in an additional 5 pieces, with at least 3 pieces.
The transparent parts of the lighting fixtures should be separately shipped with at least 8 pieces.
Rubber aging tests should provide 3 to 5 pieces of 35156 rubber blocks.
Insulate resistance testing for plastic enclosures requires 2 pieces of plastic sheets with a diameter of 150-60mm. If the dimensions allow, the plastic enclosures can be tested directly.
Generally, 1-2 finished products are required.

Limitation requirements for surface resistance of non-metallic casings of explosion-proof equipment
In hazardous areas with explosive dust or gases, such as coal powder, flour, etc., static electricity may cause fires or explosions, posing a significant risk. Therefore, it is advisable to minimize the use of insulating materials in explosive hazardous areas. When selecting electrical insulating materials, consider maintaining a low insulation resistance to prevent discharge when non-metallic components come into contact with charged components. For non-metallic insulating materials, the antistatic ability of the equipment can be assessed by measuring the surface resistance of the equipment housing.
Surface Resistance, measured in ohms (Ω), refers to the resistance between two electrical contacts on the measuring surface.
In accordance with the requirements of the IEC 60079 series standards:
1. In II Division explosive gas environments, when the surface area of the non-metallic housing of electrical equipment exceeds a certain limit value (as shown in Table 1), a surface resistance test of the non-metallic material is required to verify that: By selecting the material, the surface resistance meets at least one of the following requirements during measurement according to IEC 60079-0 26.13:
At ≤1 GΩ, (505)% relative humidity;
At ≤100 GΩ, (305)% relative humidity.
2. In environments with Category III explosive dust, if the surface area of the non-metallic housing of electrical equipment does not exceed 500 mm², the risk of static electricity can be disregarded; if it exceeds this limit, a surface resistance test must be conducted for verification. The requirements for assessment are the same as those for the surface resistance test limit in Category II gas environments. For fixed installation equipment that cannot meet the surface resistance limit, an "X" can be added after the " explosion-proof " label, a corresponding warning sign should be placed on the equipment, and the user should be informed in the user manual.
Explosion-proof Certification Application Consulting Service - Shenzhen Zhongnuo Testing Technology Co., Ltd.