Regarding the classification of Ex certification levels, it actually refers to the categorization of Ex electrical equipment based on different usage locations, mainly including Category I, Category II, and Category III Ex Certificates of Conformity.

Category I Ex Certificate of Conformity is a certification document for equipment used in underground coal mines, and is generally used together with the equipment's MA (Mine Safety) Certificate.

Category II Ex Certificate of Conformity applies to Ex equipment for non-mining explosive gas environments, such as equipment used in petrochemical, gas, oil depot and other locations.

Category III Ex Certificate of Conformity applies to Ex equipment for non-mining explosive dust environments, such as equipment used in painting, grinding, feed, food and other venues.

In addition, qualified domestic Ex certification bodies include Tianjin PCEC, Nanyang CNEX, Shanghai NEPSI, Shanghai Coal Science Research Institute, Changsha Institute of Mining Research, Suzhou Electrical Apparatus Science Research Institute, CQC, etc. These institutions conduct tests and certifications in accordance with Ex certification standards such as the GB/T 3836 series.

On Ex equipment, an Ex mark is usually printed, such as "Ex db ib IIC T4 Gb". Among them, "Ex" indicates explosion protection, "db ib" refers to the Ex protection types adopted by the equipment, "IIC" means the equipment is suitable for IIC group gases in explosive gas environments, "T4" is the temperature class, and "Gb" refers to the equipment protection level (EPL).

This information helps you better understand the classification of Ex certification levels. If you have other needs or questions regarding Ex certification, please feel free to consult STS at any time!