Inspection standards for explosion-proof electrical equipment
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Overview
1. This standard applies to explosion-proof electrical equipment and connecting cables used underground in mines and above ground in environments with gas and coal dust explosions.
2. Explosion-proof electrical equipment and small electrical appliances must have permanent explosion-proof markings (Exdi), coal mine safety markings (MA), and product nameplates. Equipment without the "explosion-proof marking" or "coal mine safety marking" is considered explosion-proof, and equipment without the "nameplate" is considered incomplete.
3. Before lowering explosion-proof electrical equipment and small electrical appliances into the mine, they must be inspected by a dedicated explosion-proof inspector, have an "Explosion-proof Inspection Certificate" affixed, and be issued a "Mine Entry Permit." Absence of the "Explosion-proof Inspection Certificate" during on-site inspection is considered explosion-proof.
Casing
1. Any location where a shaft passes through the flameproof enclosure wall must be equipped with a flameproof bearing cap; otherwise, the enclosure is considered explosion-proof.
2. Any deformation of the flameproof enclosure exceeding 50mm in length or a concave or convex depth exceeding 5mm is considered explosion-proof.
3. Open welds on the flameproof enclosure indicate a failure; severe rust or flaking rust indicates a failure; and extensive paint peeling indicates an incomplete condition.
4. Cracks or loosening of the terminal block passing through the flameproof cavity indicate a failure.
5. The sealing gasket inside the observation window of the flameproof enclosure must be made of a metal-clad, non-combustible material with a sufficient strength. The gasket thickness must not be less than 2mm. For enclosures with a net volume of no more than 100cm³, the gasket width must not be less than 9.5mm. Otherwise, it indicates a failure. Scratches on the observation window glass less than 1mm deep indicate an incomplete condition. Otherwise, it indicates a failure.
