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In the previous article, we provided a detailed introduction to the IP protection level requirements for explosion-proof equipment in places with combustible dust. this paperZhongnuo TestingThen, the IP protection level requirements for equipment used in explosive gas locations were introduced.
1. Increased safety electrical equipment "e"
(1) The protection level defined in GB/T4942.1-2006 and GB4208-2008 shall comply with the provisions in a) or b), except as otherwise specified in 4.9.2, 4.9.3 or Chapter 5.
a) The shell with exposed live parts inside shall have a protection level of at least IP54;
b) The internal components specified in section 4.5 are only equipped with insulated live parts shells and have a protection level of at least IP44.
(2) The casing of electrical equipment can be equipped with drainage holes or ventilation holes to prevent condensation water from accumulating. The requirements related to equipment categories are as follows:
a) Class I equipment, meeting the protection level requirements of 2.1.1;
b) Class II equipment, drainage holes or ventilation holes can reduce the protection level provided by the casing according to 2.1.1, but their protection level is not lower than IP44 in case 2.1.1a) or IP44 in case 2.1.1b).
(3) If the enclosure contains an intrinsic safety type "i" circuit or system that complies with GB3836.4-2010, or components of an intrinsic safety circuit or system, then a) the enclosure cover that allows contact with live non intrinsic safety circuits should be in accordance withGB3836According to the requirements in Table 12, a) warning signs should be installed, or b) when the equipment casing is opened, all live parts of non intrinsic safety "i" circuits should be equipped with isolation covers with a protection level of at least IP30
2. Intrinsic safety electrical equipment "i"
The protection level of intrinsic safety equipment depends on the applicable location. For equipment that meets the separation spacing requirements in Table 5 of GB3836.4, the protection level of the enclosure shall not be lower than IP20. Equipment that meets the separation spacing requirements of Appendix F of 3836.4 should achieve a level 2 pollution prevention rating.
3. Positive pressure electrical equipment "p"
The positive pressure casing of positive pressure equipment should have a protection level that meets the following table (IP44 may be required on damp or dusty mining surfaces).
4. Liquid immersed electrical equipment "o"
The structure of Ex equipment should ensure sufficient protective liquid. According to the expected equipment protection level requirements, monitoring devices, indicators, or liquid level control safety devices with automatic shut-off switches can be used to ensure sufficient liquid without specific protection level requirements.
5. Sand filled electrical equipment "q"
(1) The enclosure of electrical equipment, electrical equipment components, or Ex elements protected by sand filled mold "q" should meet the requirements of IP54 protection level specified in GB/T4208 under normal operating conditions, that is, when all openings are closed during normal use. If the protection level is IP5 or higher and the enclosure is not airtight, the enclosure should be equipped with a breathing apparatus. The enclosure using respiratory devices should at least meet the requirements of IP54 protection level specified in GB/T4208. A protective test should be conducted on the empty box without filling. At the end of the waterproof test, there should be no visible water inside the box.
(2) If used only in clean and dry rooms, the protection level can be reduced to IP43. For this type of equipment, the symbol "X" should be added after the explosion-proof certificate number in accordance with the marking requirements of GB3836.1, and the special usage conditions specified in the explosion-proof certificate should specify the usage restrictions in detail.
(3) When Ex components protected by sand filled "q" are installed in other explosion-proof types of enclosures that comply with GB3836.1, the protection level of the external enclosure should be at least IP54. If the installation position of the Ex component is such that it cannot be affected by any small amount of water that may enter the casing, there is no need to specify the protection level of the internal enclosure.
6. Other explosion-proof types
Other explosion-proof types (such as explosion-proof, sealed, and spark free equipment) are not specifically guided in the standards, so the protection level is determined based on actual needs.
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