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I. What is explosion-proof certification? In environments with explosive gases, equipment used must be designed in accordance with explosion-proof standards and must obtain an explosion-proof certification. II. What are explosion-proof electrical equipment? Electrical equipment used in areas where gases and vapors with explosive hazards are present. The main items include explosion-proof changeover switches, explosion-proof air switches, explosion-proof magnetic starters for industrial use, explosion-proof control buttons, explosion-proof operation levers, explosion-proof limit switches, explosion-proof latches, explosion-proof wiring boxes, explosion-proof junction boxes, explosion-proof pipe fittings and sealing materials, as well as explosion-proof lighting fixtures. III. Classification of explosion-proof electrical equipment 1. Underground mines (Class I products) Used in areas underground in coal mines. 2. Above-ground mines (Class II products) Used in areas above ground, as well as in petroleum and petrochemical facilities, refineries, chemical plants, mechanical workshops, and other areas where there is a risk of explosive gases. 3. Dusty areas (Class III products) Used in places with dust particles or floating debris. IV. Classification, grading, and grouping of explosive substances 1. Explosive products can be divided into 3 classes: (1) Class I: Methane in mines ； (2) Category II: Other explosive gases other than coal mine gas (standard explosion protection certification) ； Class II electrical equipment can be further classified according to the type of explosive environment in which it is used: II A: Propane; II B: Ethylene; II C: Hydrogen. (3) Class III: Explosive dusts (explosion protection certification for dusts containing fibers) ； Classification of Class III electrical equipment ； Ⅲ A: Flammable fluff Ⅲ B: Non-conductive dust Ⅲ C: Conductive dust Note: Currently, most products developed at home and abroad are of type I and type II. Abroad, ATEX testing for Category I devices cannot be carried out at domestic testing facilities. V. Regional classification for explosion protection certification: China adopts a method equivalent to that of IEC for classifying areas with explosive hazards. **Standard GB 50058-92 specifies that explosive gas hazardous areas are classified into three categories based on their level of danger: Zone 0, Zone 1, and Zone 2. (1) Zone 0: An environment in which explosive gas mixtures are present continuously or for an extended period of time ； (2) Zone 1: An environment in which an explosive gas mixture may occur during normal operation; (3) Zone 2: An environment in which an explosive gas mixture cannot occur during normal operation, or in which such a mixture exists only for a short period of time if it does appear. Note: Zones 0, 1, and 2 are actually the locations where products are sold. https://pic4.zhimg.com/80/v2-5701d54f054e508604eb883bed84936f_720w.jpg VI. There are various types of explosion-proof products, but the two most commonly used ones are as follows: 1. Flameproof type: The explosion-proof rating for this type is “d”; such equipment is suitable for use in Zones 1 and 2. For flameproof products, the main consideration is the structure, specifically the design of the enclosure. 2. Intrinsic safety type: The explosion protection mark is “i”; this type of explosion protection can only be used in low-voltage equipment, and such equipment is suitable for categories 0, 1, and 2. Intrinsic safety products focus primarily on the circuitry, specifically on PCB circuit design.