Shenzhen ZhongNuo Testing Technology Co., Ltd. is based in South China and specializes in explosion-proof certification and coal mine safety certification application consulting services, offering a one-stop explosion-proof technology consulting service.
List of Domestic Explosion-Proof Certification Agencies:
1. Nanyang CNEX
2. Shanghai Coal Research Institute
3. National Electrical Appliance Quality Supervision and Inspection Center
4. Guangdong CQCEx National Explosion-Proof Equipment Quality Supervision and Inspection Center
5. National Coal Mine Explosion-Proof Safety Product Quality Supervision and Inspection Center
6. Jiamusi Explosion-Proof Institute
7. Tianjin PCEC
8. Shanghai NEPSI
9. Beijing Coal Research Institute CCRI, etc.
For applicants, the type of explosion-proof classification and the level of explosion-proof they choose are essentially the same across all recognized institutions. They are all authorized institutions that have undergone national certification, with testing conditions that meet standard requirements, adhering to the same standards and conducting similar testing. Under the same conditions, choosing institutions that offer more affordable services at a lower price has become an inevitable trend, and this is also an important reason why new explosion-proof enterprises are gaining popularity.

Is "intrinsically safe certification" the same as "explosion-proof certification?" What are the differences between them?
Explosion-proof certification refers to a safety certification for equipment and products used in explosive hazard areas.
Products must take certain measures to meet the requirements of explosion-proof certification standards; we refer to these as explosion-proof protection types.
Common explosion-proof protection types include intrinsic safety, flameproof, positive pressure, and increased safety, etc.
It is apparent that intrinsic safety is just one type of explosion-proof protection.
Different explosion-proof protection types have varying design requirements for the product.
intrinsic safety is achieved by limiting electrical energy, even in the event of a fault.
This type of explosion-proof protection generates insufficient energy to ignite the surrounding explosive environment.
Therefore, intrinsic safety requirements limit the current, voltage, capacitance, inductance, etc., of electrical equipment, and are generally suitable for low-power devices.
Additionally, specific requirements are in place for the power supply method, housing material, and wireless transmission of intrinsically safe equipment.
As a third-party consulting firm that has long focused on explosion-proof certification.
ZhongNuo Inspection has dedicated engineers specializing in intrinsically safe circuit and structural design.
We offer technical consulting services for explosion-proof circuit design, drafting, and modifications. We have extensive experience in designing and obtaining certifications for intrinsic safety ia, ib, and ic explosion-proof classifications.
If you require certifications in this area, feel free to send us a private message!

Non-metallic surface resistance limit requirements for explosion-proof equipment
In hazardous areas with explosive dust or gases/vapors, such as coal powder and flour, static electricity can cause fires or explosions, posing significant danger. Therefore, it is advisable to minimize the use of insulating materials in explosive hazard areas. When selecting electrical insulating materials, consider maintaining low insulation resistance to prevent discharge when non-metallic components come into contact with charged components. For non-metallic insulating materials, the antistatic capability of the equipment can be assessed by measuring the surface resistance of the equipment's 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 Category II 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 must be conducted on the non-metallic material to ensure that: by selecting the material, the surface resistance meets at least one of the following requirements when measured according to IEC 60079-0 26.13:
At ≤1 GΩ, (505)% relative humidity;
At ≤100 GΩ, (305)% relative humidity.
2. In environments with Class 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 limits in Class II gas environments. For fixed installation equipment that cannot meet the surface resistance limits, an "X" can be added after the "Explosion-proof" sign, a corresponding warning sign should be placed on the equipment, and the user should be informed in the user manual.

What are the requirements for enterprises to apply for explosion-proof certification -- Shenzhen Zhongnuo Testing Technology Co., Ltd.
For businesses, there are no special requirements for applying for domestic explosion-proof certificates (except for the explosion-proof 3C certification).
Primarily, it's to check if the product meets the explosion-proof standards and whether the required certification documents can be provided.
If the product falls under the explosion-proof 3C certification category, the applicant must have a production factory (OEM/ODM is also acceptable).
Because the explosion-proof 3C certification is a certification model that involves both type testing and factory audit.
In addition to product testing, an annual audit of the manufacturing facility is required.
Explosion Proof Certification Application Consulting Service - Shenzhen ZhongNuo Testing Technology Co., Ltd.