Explosion-proof is divided into class I explosion-proof and class II explosion-proof; class I explosion-proof is suitable for the underground environment of coal mines, and class II explosion-proof is suitable for other environments except coal mines.

Explosion-proof grade statement

Definition of explosion-proof equipment: electrical equipment that will not cause ignition of the surrounding explosive atmosphere under specified conditions.

Divided into three categories

Class I: electrical equipment in coal mines;

Class II: Electrical equipment for all other explosive gas atmospheres except coal mines and underground mines.

Class II can be further divided into classes IIA, IIB, and IIC. The equipment marked with IIB can be applied to the operating conditions of IIA equipment; IIC can be applied to the operating conditions of IIA and IIB.

Class III: Electrical equipment in explosive dust atmospheres other than coal mines.

Class IIIA: flammable flying flakes; Class IIIB: non-conductive dust; Class IIIC: conductive dust.

Maximum surface temperature: The highest temperature reached by any part of the electrical equipment that may cause the surrounding explosive atmosphere to ignite when the electrical equipment works under the most unfavorable operating conditions within the specified range. The maximum surface temperature should be below the flammable temperature.

For example: the ignition temperature of the explosive gas in the explosion-proof sensor environment is 100 °C, then the maximum surface temperature of any part of the sensor in the worst working state should be lower than 100 °C.