CompEx vs ATEX — What's the Difference?
CompEx and ATEX are two of the most important terms in hazardous area electrical work — but they are often confused. Understanding the difference is fundamental to understanding how safe electrical work in explosive atmospheres is assured.
CompEx — Competency Certification
CompEx is a competency assessment scheme that certifies the ability of electrical workers to carry out installation, inspection, and maintenance of electrical equipment in explosive atmospheres. CompEx assesses people — it is not about equipment. A CompEx certificate proves that the holder has demonstrated the knowledge and practical skills required to work safely with Ex equipment in hazardous areas.
CompEx is administered by JTL Training and is based on the IEC 60079 series of standards. It is the UK industry standard for demonstrating competency under the DSEAR (Dangerous Substances and Explosive Atmospheres Regulations 2002) requirement for competent persons.
ATEX — Equipment Certification
ATEX (ATmosphères EXplosibles) is a certification system that applies to electrical and mechanical equipment intended for use in explosive atmospheres. ATEX certifies the equipment — it proves that a junction box, motor, instrument, or gland meets the IEC 60079 requirements for safe use in a specified zone, gas group, and temperature class.
In the UK post-Brexit, the equivalent to ATEX is the UKEX marking under the Equipment and Protective Systems Intended for Use in Potentially Explosive Atmospheres Regulations 2016. The technical requirements are aligned with ATEX/IEC 60079.
How CompEx and ATEX Work Together
| Aspect | CompEx | ATEX |
|---|---|---|
| What it certifies | The competency of the worker | The safety of the equipment |
| Who holds it | Electricians and instrument technicians | Manufacturers and importers |
| Standard basis | IEC 60079 applied competency | IEC 60079 equipment design |
| UK regulation | DSEAR competency requirement | Equipment regulations (UKEX) |
| Renewal | Every 5 years | When design changes or standard revises |
Safe hazardous area electrical work requires both. ATEX-certified equipment installed by an incompetent worker is unsafe. CompEx-certified workers using non-ATEX equipment are non-compliant. Both the worker's competency and the equipment's certification must be in place. CompEx provides the knowledge to select and verify ATEX-certified equipment correctly.
DSEAR — The Connecting Framework
DSEAR (Dangerous Substances and Explosive Atmospheres Regulations 2002) is the UK regulation that brings both together. DSEAR requires employers to: carry out a risk assessment, classify hazardous areas into zones, ensure only appropriate certified (ATEX/UKEX) equipment is used, and ensure that all persons carrying out work in hazardous areas are competent — for which CompEx is the accepted standard.
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