Basic safety knowledge for explosion-proof electrical circuits

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In environments with explosion hazards, the selection of the installation location for electrical circuits, the choice of wiring methods, the selection of conductor materials, and the choice of connection methods should all be determined based on the level of hazard in the environment. 　　1. Location selection Electrical wiring should be installed in locations where the risk of explosion is low or where it is far away from the source of ignition. 　　2. Selection of installation methods: In explosive hazardous environments, electrical wiring mainly includes explosion-proof steel pipe wiring and cable wiring. 　　3. Isolation sealing: When grooves for electrical wiring, as well as protective pipes, cables, or steel pipes, pass through partition walls or floors between areas with different levels of explosion hazard, they must be tightly sealed using non-combustible materials. 　　4 Selection of conductor materials: In areas classified as Zone 1 under the hazardous area classification for explosive atmospheres, power distribution circuits shall use copper-core conductors or cables. In locations with severe vibration, multi-strand copper core flexible wires or multi-strand copper core cables should be used. Aluminum-core power cables shall not be used in coal mines. 　　Within Zone 2 of the hazardous areas with explosion risks, power circuits shall use aluminum-core conductors or cables with a cross-sectional area of 4 mm² or more; for lighting circuits, conductors with a cross-sectional area of 2.5 mm² may be used. Aluminum-core conductors or cables of 35 mm² and above. 　　5 Permissible current-carrying capacity: When selecting the cross-sectional area of insulated conductors and cables in Zone 1 and Zone 2, the permissible current-carrying capacity of the conductors shall not be less than 1.25 times the rated current of the fuse element and the setting current of the long-time overcurrent release of the circuit breaker. The permissible current carrying capacity of the branch circuit leading to the low-voltage squirrel-cage induction motor shall not be less than 1.25 times the rated current of the motor. 　　6 Connection of electrical circuits: The intermediate connections of the electrical circuits in Zones 1 and 2 must be located inside, near an explosion-proof junction box or connector box suitable for that hazardous environment. In Zone 1, flameproof junction boxes should be used; in Zone 2, increased-safety junction boxes may be used. 　　When aluminum-core cables or wires are used for electrical wiring in Zone 2, there must be reliable Article source: http://www.bzc51.cn/news/news103.html