Many dust generated during production, processing, transportation, and storage are flammable. If the dust is mixed with air in an appropriate proportion, the dust can quickly burn and generate huge explosive pressure when ignited. In places where such combustible materials may occur, explosion-proof electrical equipment is usually required, so appropriate precautions must be taken to ensure that all such electrical equipment is adequately protected to reduce the possibility of igniting an external explosive environment. In electrical equipment, potential ignition sources include arcs and sparks, hot surfaces, and friction sparks. Places where hazardous amounts of dust, fibers, and flying debris are present in the air are classified as hazardous areas, and are classified into three hazardous areas according to their hazard level. In general, one of the following two methods is used to ensure the electrical safety of electrical equipment: one method (as long as feasible) should install the electrical equipment outside of hazardous areas, and the other method should be designed, installed, and maintained according to the recommended methods for electrical equipment usage. Electrical equipment may ignite combustible dust through the following main ways: - - - - The surface temperature of electrical equipment is higher than the minimum ignition temperature of the relevant dust. The temperature of dust ignition is related to the dust performance, the state of dust existence, the thickness of the dust layer, and the geometric shape of the heat source Arcs or sparks in electrical components such as switches, contacts, rectifiers, brushes, and similar components- Accumulated static charge discharge- Radiated energy (such as electromagnetic radiation)--- Mechanical sparks, frictional sparks, or frictional heating related to electrical equipment. To avoid the risk of ignition, the following points should be achieved: - The surface temperature of electrical equipment that may accumulate dust or come into contact with dust clouds must be maintained below the temperature limit specified in this section-- Any component that generates electric sparks or whose temperature exceeds the temperature limit specified in GB 12476.2 should be placed in an enclosure that is sufficient to prevent dust from entering people, or the energy of the circuit should be limited to avoid generating arcs, sparks, or temperatures that can ignite combustible dust; - - to avoid any other ignition source. Several explosion-proof technologies are used for electrical equipment in hazardous locations. This section describes the safety technical characteristics of this explosion-proof type and specifies the requirements to be adopted. To ensure the safety of electrical equipment in hazardous locations, it is most important to follow standard selection and installation procedures. If electrical equipment operates under its rated conditions and is installed and maintained in accordance with relevant codes or regulations (such as preventing overcurrent, internal short circuits, and other circuit faults), it must comply with the requirements of this part of GB 12476 and only have the required safety level. In particular, it is most important to limit the duration and severity of internal or external faults to the extent that electrical equipment can withstand and will not be damaged. For example, design should comply with the principles of IEC 60079-25 and installation should be carried out in accordance with the requirements of GB 12476.2