Explosion Proof Brass Gland | EExd 501/453 20MM is a specific and critical component for hazardous area installations. Let's break down exactly what this designation means and where it's used.
Decoding the Name & Standards
Explosion Proof: This is the overall protection concept. It means the gland is designed to contain an explosion originating inside the enclosure (e.g., from a sparking motor or arcing connection) and prevent it from igniting the surrounding hazardous atmosphere.
Brass: The material of construction. Brass is chosen because:
It is corrosion-resistant, especially important in industrial, marine, or outdoor environments.
It is spark-resistant (non-ferrous). In the rare event of an impact, it is less likely to create incendive sparks compared to steel.
It has good mechanical strength and thread-forming properties.
Gland (Cable Gland): A device for securing the end of an electrical cable to equipment, providing:
Strain Relief: Prevents cable pull from transferring to electrical terminations.
Sealing: Protects against the ingress of dust and moisture (to a specified IP rating).
Earth Continuity: For metal-armoured cables, it ensures the braid/armour is effectively bonded to the enclosure for safety.
EExd: This is the older European (CENELEC) marking.
EEx: Indicates it complies with European Explosion Protection standards.
d: Denotes the "Flameproof" protection type (now called "Explosion Proof" in IEC terminology). The housing can withstand an internal explosion.
501/453: This is the critical part linking to the newer IECEx / ATEX system.
501: Refers to the British Standard BS EN 60079-1, which is the direct implementation of the international IEC 60079-1 standard for "Flameproof Enclosures 'd'".
453: Refers to the British Standard BS EN 50262, which specifies the metric dimensions and requirements for cable glands.
20MM: The metric thread size of the entry hole on the equipment where this gland will be installed. This gland will have a M20 x 1.5 male thread to fit into a tapped M20 hole. It also indicates the typical cable entry range it is designed for (e.g., for cables with an outer diameter of approximately 8-13mm, but always check the manufacturer's data sheet).
Modern Equivalent & Hazardous Area Classifications
ATEX/IECEx Marking: A modern gland for the same purpose would be marked as:
Ex d IIC / Ex d IIB (Gas Groups) Gb (Equipment Protection Level - "High" level of protection).
IP68 or similar (Ingress Protection rating).
-20°C ≤ Ta ≤ 40°C (typical ambient temperature range).
Key Features of an Ex d Flameproof Gland:
Robust Construction: Heavier and more substantial than a standard gland.
Precision Machining: The flame path—the precise gap between the gland body and its nut/sealing ring—is machined to strict tolerances defined in IEC 60079-1. This path cools exploding gases below the ignition temperature of the external atmosphere.
Effective Sealing: Includes multiple sealing elements (e.g., compression seal, O-ring) to meet the required IP rating and maintain the integrity of the flame path.
Certification: Must be supplied with a test certificate from a notified body (e.g., Baseefa, SIRA, PTB, UL) proving compliance.
Typical Applications
Used wherever flammable gases, vapors, or dusts may be present:
Oil & Gas refineries and platforms
Chemical and pharmaceutical plants
Paint spray booths
Grain silos and flour mills (combustible dusts)
Petrochemical storage facilities
Gas pipelines and compressor stations
Installation is CRITICAL
Correct Selection: Ensure the gland is certified for the specific zone (Zone 1 or 2 for gases) and gas group (IIC being the most stringent) of your area.
Correct Cable: Use the correct cable type (e.g., SWA - Steel Wire Armoured) that the gland is designed for.
Torque: Tighten the gland components (especially the flameproof nut) to the manufacturer's specified torque. Overtightening can damage the flame path; undertightening can compromise the seal.
Earth Continuity: For metal-armoured cables, you must ensure the armour is properly clamped and makes excellent electrical contact with the gland body.
Integrity: Never mix and match parts from different manufacturers or gland types. This voids the certification and safety.
In summary, you are looking at a high-integrity, brass, flameproof cable gland with a metric M20 thread, designed to maintain the explosion protection of a piece of equipment in a hazardous area by securing and sealing the cable entry point. Always verify its certification is valid for your specific application.
https://store.unigulfsupply.com/product/explosion-proof-brass-gland/