What should be done with Ex equipment that has no readable marking or certificate?
Abstract
Treat it as unproven. Record a defect, decide on isolation by risk, and try to trace it to its certificate through serial numbers, tags and site records. If traceability is found, add a non-damaging identification label; if not, replace the item.
Treat it as unproven until it is identified. Without a marking or certificate nobody can show that the item suits the zone, gas group and temperature class, or know its specific conditions of use, so it must be recorded as a defect. Then trace it back to its certificate using serial numbers, tag numbers and site records. If that works, add a separate identification label that does not damage the enclosure; if it does not, replace the item.
Short answer
- Inspection finding: the first checks of an IEC 60079-17 schedule (equipment suits the EPL or zone, group and temperature class) cannot be answered, so the item fails them.
- Immediate action: the person responsible for the installation decides, by risk, whether the item may stay energised until the question is resolved. In Zone 0 or Zone 1 isolation is the safe default.
- Traceability is allowed: IEC 60079-17 accepts other ways to link the item to its certification details, such as extra labels with unique tag or serial numbers, or references to installation databases, as long as fixing the label does not reduce the integrity of the equipment.
- No traceability: replace the item. Equipment without an acceptable certificate may be used only where suitable certified equipment cannot be obtained, with a justification recorded in the verification dossier (IEC 60079-14:2007).
- Never copy a marking onto an unknown item from a similar-looking one.
Why a missing marking is a real defect
The marking is the only part of the safety case that travels with the equipment. It carries the type of protection, equipment group, temperature class or maximum surface temperature, EPL, ambient range and certificate number. The certificate number leads to any "X" (specific conditions of use) that the installer must meet, such as a restricted ambient temperature, impact protection or a cable temperature rating.
Two items that look identical can differ in exactly these points: one enclosure may be IIB and its neighbour IIC, one motor T3 and another T4. Equipment may also have been repaired, rewound or modified since it was supplied. So an inspector cannot "assume it is the same as the others" and close the finding.
How to trace the item
Work through the evidence in order and stop as soon as the identity is certain:
- Look for other markings on the item. Many items carry a serial number or a second label inside the terminal cover, on the motor frame or on an internal chassis. Check with the item isolated and the area made safe.
- Search site records. The equipment register or inspection database, purchase orders, loop drawings, earlier inspection photographs and the verification dossier often give the tag, model and certificate number.
- Ask the manufacturer. With a serial number or model, the manufacturer can usually confirm the certified version, its certificate and the specific conditions of use.
- Verify the certificate. For an IECEx certificate, check the IECEx online system: the scheme states that the online certificate is the controlled master copy, and if a certificate is not on the system it does not exist. For an ATEX type-examination certificate, confirm it with the notified body that issued it. Category 3 equipment, and Category 2 non-electrical equipment, are assessed by internal production control and have no type-examination certificate (Directive 2014/34/EU, Article 13), so for them the evidence is the EU declaration of conformity and the manufacturer's documentation.
- Fit an identification label. Once traced, attach a label with the tag or serial number that links to the record. Use a method that does not drill, glue or tape over a flamepath, gasket or enclosure wall in a way that affects the protection.
- Update the records. The register must be able to track replacements, because a repaired or replacement item may have a different marking from the original.
| Situation | What to do |
|---|---|
| Marking illegible, serial number readable | Trace through manufacturer and records, add identification label |
| Marking painted over | Clean carefully without damaging the label, record as a finding |
| No marking, no records, unknown origin | Isolate by risk, replace with certified equipment |
| Marked, but certificate not found | Treat as not proven; check for counterfeit or wrong number; replace if unresolved |
| Old equipment certified to withdrawn standards | Assess against the standards that applied when it was installed |
Old plants and pre-ATEX equipment
IEC 60079-17:2023 says that, for older installations, equipment and installation details should be referenced to the standards that applied when they were installed, which may not have been IEC standards. In Great Britain, HSE guidance on DSEAR (L138) says that equipment already in use in the EU before July 2003 may stay in service if the employer has assessed it and can show that the fire and explosion risks are eliminated or reduced so far as reasonably practicable. That relief still depends on knowing what the equipment is. An unidentifiable item cannot be assessed, whatever its age.
Example: During a close inspection on a 1990s tank farm, two junction boxes have nameplates bleached unreadable. One still shows a serial number inside the lid; the manufacturer confirms an EEx e II T6 box (plain group II, which covers all gas subgroups) and its certificate, and the site fits a stainless tag plate on the mounting bracket. The other has no number and is not in any record, so it is isolated and replaced.
Common mistakes
- Closing the finding because the item "has always been there". Age is not evidence of suitability.
- Stamping a new marking from a similar item. That creates a false declaration and may hide a lower group or temperature class.
- Gluing labels onto flamepaths or covers. The identification method must not reduce the integrity of the equipment.
- Fixing the label but not the record. The register, not the label alone, is what lets later inspectors check the item.
Related on excodex
- Common Ex inspection findings and how to fix them
- How to verify that an Ex certificate is genuine
- Can Ex equipment be painted or have extra labels stuck on it after installation?
- What must be recorded in the Ex equipment register of an installation?
- Tool: Ex marking check
Standards and further reading
- IEC 60079-17:2023 (edition 6), inspection and maintenance of electrical installations, public preview: cdn.standards.iteh.ai; full text of the 2007 edition (IS/IEC 60079-17:2007) with the traceability provision: law.resource.org
- IEC 60079-14:2024, electrical installations design, selection and installation, preview: cdn.standards.iteh.ai; 2007 text on equipment without certificates (AS/NZS 60079.14:2009): archive.org
- Directive 2014/34/EU, Article 13, conformity assessment procedures by equipment category: legislation.gov.uk
- IECEx, frequently asked questions on the certified equipment scheme: iecex.com
- HSE L138, Dangerous Substances and Explosive Atmospheres Regulations 2002, Approved Code of Practice and guidance (2nd edition 2013): hse.gov.uk
This article is general technical information prepared by the excodex editorial team. It does not replace the applicable standards, the equipment certificates and instructions, national regulations or the assessment of a competent person.