What are the requirements for explosion-proof electrical distribution boxes and lighting cable lines?
电缆线路要求： Requirements for explosion-proof electrical distribution boxes and lighting cables:
在室外和易进水的地方，与设备引入装置相连接的电缆保护管的管口，应严密封堵。 1. Outdoors and places where water is easy to enter, the mouth of the cable protection pipe connected to the equipment introduction device should be tightly sealed. (GB50257-2014 Article 5.2.6)
防爆电气设备、接线盒的进线口，引入电缆后的密封应符合下列要求：（GB50257-2014第5.2.3条） 2. The inlet of explosion-proof electrical equipment and junction boxes shall be sealed after the cable is introduced: (GB50257-2014 Article 5.2.3)
1) Electrical equipment inlets with cable head cavities or sealed boxes. After the cable is introduced, the solidified sealing filler should be poured. The depth of the plug should not be less than 1.5 times the diameter of the lead-in and should not be less than 40mm.
2) When connecting cables with electrical equipment, a lead-in device suitable for the outer diameter of the cable should be selected. When the lead-in device of the selected electrical equipment is not compatible with the outer diameter of the cable, a transition wiring method should be used. Connect in the corresponding explosion-proof terminal box.
电缆线路穿过不同危险区域或界壁时，必须采取下列隔离密封措施：（GB50257-2014第5.2.2条） 3. When the cable line passes through different dangerous areas or boundary walls, the following isolation and sealing measures must be taken: (GB50257-2014 Article 5.2.2)
1) In the cable trench at the junction of the two levels, sand filling, fire blocking or fire blocking walls should be adopted.
2) Cables should be protected through partition walls, floors, floors, and mechanically vulnerable areas that are shared with adjacent areas; the remaining holes should be tightly blocked.
再填塞密封胶泥。 3) At the mouths of the two ends of the protection pipe, the surrounding of the cable should be blocked with non-combustible fibers tightly, and then the sealing glue should be filled.
电缆采用金属密封环引入时，贯通引入装置的电缆表面应清洁干燥；涂有防腐层时，应清除干净后再敷设。 4. When the cable is introduced with a metal sealing ring, the surface of the cable passing through the introduction device should be clean and dry; when it is coated with an anticorrosive layer, it should be removed before laying. (GB50257-2014 Article 5.2.5)
防爆电气设备、接线盒的进线口，引入电缆后的密封应符合下列要求：（GB50257-2014第5.2.3条） 5. The inlet of explosion-proof electrical equipment and junction boxes shall be sealed after the cable is introduced: (GB50257-2014 Article 5.2.3)
a) When the outer sheath of the cable must pass through the elastic sealing ring or sealing packing, it must be squeezed tightly by the elastic sealing ring or sealed by the sealing packing.
b) For cables with an outer diameter equal to or greater than 20 mm, when assembling components to prevent the cable from being pulled out at the isolation seal, tighten the cable's bolts after the cable is tightened or sealed.
c) Cable entry devices or equipment inlets shall be sealed and shall meet the following requirements:
1) A hole in the elastic sealing ring in the device should seal a cable;
2) The cross section of the sealed cable should be approximately circular;
与电缆外径允许差值为±1mm； 3) The elastic sealing ring and metal pad should match the outer diameter of the cable. The allowable difference between the inner diameter of the sealing ring and the outer diameter of the cable is ± 1mm;
4) After the elastic sealing ring is pressed, the cable should be squeezed evenly along the circumference.
电缆配线引入防爆电动机需挠性连接时，可采用挠性连接管，其与防爆电动机接线盒之间，应按防爆要求加以配合，不同的使用环境条件应 6. When the cable wiring is introduced into the explosion-proof motor and flexible connection is required, a flexible connection tube can be used. The connection between the cable and the explosion-proof motor junction box should be in accordance with the explosion-proof requirements. Different operating environmental conditions should be used.
Using flexible connecting pipes of different materials. (GB50257-2014 Article 5.2.4)