Division of explosion-proof electrical equipment's explosion-proof grades is based on the category of equipment used, the temperature group of explosive gases, and the explosion-proof type of the electrical equipment. Electrical equipment
Flameproof electrical equipment is divided into two categories: Class I is for electrical equipment used in coal mine underground; Class II is for electrical equipment used in places other than mines, distinguished by the Minimum Experimental Service Gap (MESG) or Minimum Ignition Current (MICR). Class II electrical equipment is further divided into three categories: IIA, IIB, and IIC.
The above four categories are primarily divided based on the potential spark quantities that could ignite under different operating conditions. China, along with most countries and regions in Europe and around the world, classifies 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 denoted as t (°C).