[2025 Fun Fact] Components of the flameproof enclosure introduction device

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This post was last edited by zhoudingshengs on 2025-1-17 08:51. Components of the explosion-proof enclosure insertion device: 1. “Components” of the insertion device: these include cable insertion devices, conduit sealing devices, plugs and sockets as well as cable connectors, EX seals, EX threaded pipe fittings, and insulating sleeves. 2. Threaded flameproof inlet devices shall use metric threads (M) or tapered threads (NPT); G threads are not suitable for flameproof inlet devices. The tolerance grades for metric threads (M) must meet the requirements of GB/T 197 and GB/T 2516; the precision of metric internal threads should be at least 6H or higher. Furthermore, the deepest point of any chamfer or tool withdrawal groove shall be no less than 2 mm from the outer wall surface. The thread precision of metric external threads must be at least 6g or higher; the thread length should be at least 8 mm with a minimum of 8 threads. If there is a withdrawal groove, a non-separable and non-compressible washer or similar component must be installed. All of this is to ensure that after the insertion device is installed in the housing inlet, the effective number of interlocking threads is at least 5. The male and female threads of the NPT shall meet the requirements specified in Table 5 of GB/T 3836.2-2021, namely: (1) The number of starts on the male and female threads shall be no less than 5. (2) The effective length of the external thread shall be not less than dimension “L2”, and if there is a flange, the length from the end face of the flange to the end of the thread shall not be less than “L4”. When the tapered thread mating surface consists of internal and external threaded components and is engaged for at least 4.5 turns, the requirement in item b above need not be met. 3. For the introduction devices of Class I equipment, they must meet the requirements regarding non-threaded joints as specified in clause 5.2 of GB/T 3836.2-2021. The above requirements apply only to cable entry devices that are installed separately; they do not apply to integrated cable entry devices or similar devices provided by the manufacturer as part of the enclosure.