Division of explosion-proof electrical equipment's explosion-proof grades is based on the type of equipment used, the temperature group of explosive gases, and the explosion-proof type of electrical equipment. Electrical equipment
Explosive-proof electrical equipment is divided into two categories: Category I for electrical equipment used in coal mine underground; Category II for electrical equipment used in locations other than mines, distinguished by the Minimum Experimental Service Gap (MESG) or Minimum Ignition Current (MICR). Category II electrical equipment is further subdivided into three classes: IIA, IIB, and IIC.
The above four categories are mainly divided based on the potential spark quantities that could ignite under different working conditions. China, as well as most countries and regions in Europe and around the world, classify explosive gases into these four hazard levels. The specific distinctions are as follows in the table below. Additionally, according to the ignition temperature differences of explosive gases, the groups are further divided into T1, T2, T3, T4, T5, and T6, with the ignition temperature represented by t (°C).