Standards for Explosion-Proof Requirements of Armored Pigtails

Armored pigtails used in hazardous locations must comply with explosion-proof standards, be properly certified, and installed according to zone-specific requirements to prevent ignition.

Certification and Standards

Armored pigtails intended for explosive atmospheres must meet recognized safety standards such as ATEX 114/153, IECEx, and EN 60079-14, which define design, testing, and installation requirements for electrical equipment in hazardous areas. Certification ensures that the pigtail will not act as an ignition source even under fault conditions. While cables themselves are not always legally required to be ATEX-certified, selecting cables suitable for the specific zone classification is mandatory.

Zone Classification

Before installation, the hazardous area must be classified into zones based on the likelihood and duration of explosive atmospheres: Gas zones: Zone 0 (continuous), Zone 1 (likely), Zone 2 (unlikely/short duration)Dust zones: Zone 20 (continuous), Zone 21 (likely), Zone 22 (unlikely/short duration) The armored pigtail must be selected according to the zone, ensuring the appropriate Explosion Protection Level (EPL) and temperature rating. Construction RequirementsExplosion-proof armored pigtails should have: Robust armor and sheath: Continuous metallic armor with a gas- and vapor-tight design, often with an additional PVC or thermoplastic jacket for environmental protection.

Flexible stranding: To allow installation in trays, conduits, or direct burial without compromising integrity. Temperature and impact resistance: Rated for low temperatures (e.g., -40°C) and mechanical stress. Sealed terminations: Cable entry points must prevent dust, moisture, and gas ingress, maintaining the integrity of the explosion-proof enclosure.

Installation Practices

Minimize components: Reduce the number of connectors and wires in hazardous zones to lower failure risk. Tight connections: Ensure all terminations are secure and compatible with the enclosure's explosion-proof rating. Qualified personnel: Only trained and certified electricians should perform installation and maintenance.

Acceptance testing: After installation, verify compliance with documentation, functionality, and safety systems before energizing.

Summary

To meet explosion-proof requirements, armored pigtails must be certified, zone-appropriate, mechanically robust, and properly installed. Compliance with ATEX, IECEx, and EN 60079 standards, along with careful attention to sealing, connection integrity, and qualified installation, ensures safe operation in hazardous environments.