STS is pleased to provide the following information regarding the classification standards for explosion-proof grades:

Explosion-proof electrical equipment is primarily classified into Class Ⅰ, Class Ⅱ and Class Ⅲ China Ex Certificates based on their intended application areas:

(1) Class Ⅰ China Ex Certificate: This certification is for equipment used in underground coal mine environments. It is generally used in conjunction with the device's MA Certification, indicating that the equipment can operate safely in coal mine methane gas atmospheres.

(2) Class Ⅱ China Ex Certificate: This certification applies to explosion-proof equipment used in non-mining explosive and flammable gas atmospheres. For example, equipment used in explosive and flammable areas such as the petroleum and petrochemical industry, gas supply, and oil depots must obtain a Class Ⅱ China Ex Certificate.

(3) Class Ⅲ China Ex Certificate: This certification is for explosion-proof equipment used in non-mining explosive and flammable dust atmospheres. For instance, equipment used in explosive and flammable workplaces such as spray painting, grinding, feed processing, and food processing industries must obtain a Class Ⅲ China Ex Certificate.

In addition, each letter in an Ex marking has a specific meaning. Examples are as follows:

a. Ex: Indicates a marking for electrical equipment used in gas atmospheres.

b. ib: Indicates the protection type is intrinsically safe.

c. I: Indicates a coal mine methane gas atmosphere.

d. IIC: Indicates the device is suitable for Group IIC gas and vapor atmospheres.

e. T6: Indicates the temperature class is T6, meaning the maximum surface temperature of the device does not exceed 85°C.

The following points should be noted when applying for Ex Certification:

(1) A higher explosion-proof grade is not always better; instead, a suitable grade should be selected based on factors such as product structure, installation method, and application area.

(2) The explosion-proof grade is not equivalent to the Degree of Protection (IP Rating) – these are two distinct concepts.

(3) The lower the temperature class, the higher the safety level of the device.

(4) A gas Ex Certificate is not applicable for dust environments, and similarly, a dust Ex Certificate is not applicable for gas environments.

If you require more detailed information or technical support regarding Ex Certification, please feel free to contact STS at any time.