What should I do if the nameplate marking differs from the Ex certificate?
Abstract
Treat it as a non-conformity until explained: do not install or energise the equipment; check that you have the right certificate, issue and variant, then ask the manufacturer in writing. A nameplate claiming more than the certificate covers must not be relied on.
Treat it as a non-conformity until it is explained in writing. Do not install or energise the equipment. First check that you are comparing the right certificate, the right issue and the right variant, because many differences have an innocent explanation. If the nameplate claims more than the certificate covers, or the product is not on the certificate at all, the equipment must not be used in the hazardous area until the manufacturer resolves it.
Short answer
- Stop and record. Tag or quarantine the item, photograph the nameplate and note the certificate number and issue you compared it with.
- Check your documents first. Wrong certificate, an old issue, or a certificate covering a product family can explain the difference.
- Narrower is usually fine, wider is not. A nameplate showing less than the certificate allows (a lower gas group, a narrower ambient range) can be a legitimate variant, provided that variant is listed on the certificate. A nameplate showing more (IIC instead of IIB, T6 instead of T5, Gb instead of Gc, a wider Ta) is not covered.
- Ask the manufacturer in writing, and if needed the certification body that issued the certificate, contacted through official channels.
- Never fix it on site. Changing or re-marking the nameplate is the manufacturer's job, not the installer's.
Why the match matters
The nameplate is what installers and inspectors work from in the field; the certificate is the evidence behind it. IEC 60079-0 requires the Ex marking to carry the certificate reference so that the two can be linked. The inspection schedules of IEC 60079-17 start with exactly the checks that depend on the marking: equipment suitable for the EPL or zone, correct equipment group, correct temperature class, correct circuit identification. If the marking is not backed by the certificate, each of these checks rests on an unproven claim.
Under ATEX, the manufacturer's marking, instructions and EU declaration of conformity must agree. Directive 2014/34/EU requires that literature describing the equipment does not contradict the instructions on safety aspects. A mismatch is therefore a compliance question for the manufacturer, not something a user can settle.
Common causes and what to do
| Difference found | Likely cause | Action |
|---|---|---|
| Certificate number on the label differs from the one supplied | Wrong certificate sent, or dual ATEX and IECEx numbers | Get the certificate whose number is on the label |
| Marking matches a later or earlier issue | Certificate was updated (new issue, or an addition to an ATEX certificate) | Get the issue valid for the date of manufacture and check the change history |
| Type code or variant not listed | Variant never certified, or a newer issue not yet supplied | Hold the item; ask the manufacturer and, if needed, the issuing body to confirm coverage |
| Label shows less than the certificate | Product family certificate; this variant has a lower rating | Usually acceptable if the variant is listed; use the label value |
| Label shows more than the certificate | Error, or unsupported claim | Do not use; obtain written resolution |
Old-style marking (EEx, no EPL) against a newer certificate | Different standard editions | Check that the label and certificate are for the same product generation |
| Certificate not found, or status suspended or cancelled | Possible fake, or certificate withdrawn | Check the date of manufacture against the status; escalate |
For IECEx, the online certificate system holds the controlled master version. IECEx states that a certificate not in the system does not exist, that certificates are "living" documents with a status of Current, Suspended or Cancelled, and that each new issue describes the changes made, without cancelling the earlier issues. Its FAQ advises asking the manufacturer first and contacting the issuing certification body when the question concerns the certificate itself.
A worked example
At the initial inspection of a new skid, an inspector finds a flameproof junction box marked Ex db IIC T6 Gb, -40 °C ≤ Ta ≤ +60 °C. The certificate supplied lists the same type with IIC, but T6 only up to +40 °C and T5 up to +60 °C, and the nameplate ambient range appears nowhere.
The inspector records a defect, and the box is not energised. The manufacturer explains in writing that the label was printed for a newer variant. That variant was covered by a later issue of the certificate, which had not been supplied. The new issue is checked online, its status is Current, the type code is listed and the marking matches. The documentation is corrected and the defect closed. Had the manufacturer been unable to show coverage, the box would have been replaced.
If you suspect a fake
Confirm the certificate only through the official IECEx website or the notified body's own contact details, not the supplier's. If the certificate proves false or the product is not covered, tell the supplier and, in the EU or Great Britain, the national market surveillance authority. Do not return the equipment to service.
Common mistakes
- Accepting a "close enough" match. Gas group, temperature class, EPL and ambient range are exactly what the certificate must prove.
- Comparing against a PDF from the supplier only. It may be an old issue or not the right document.
- Re-labelling to match the certificate. That is a modification of the marking and belongs to the manufacturer.
- Installing and sorting out the paperwork later. Once installed, the item is easily forgotten; resolve it first.
Related on excodex
- How to read an Ex marking: decoding II 2 G Ex db IIC T4 Gb step by step
- How to verify that an Ex certificate is genuine
- How do I read an Ex certificate number?
- What if the Ex nameplate is missing or unreadable?
- Tool: Ex marking check
Standards and further reading
- IEC 60079-0, general requirements: content of the Ex marking, including the certificate reference (edition 8, 2026); marking items paraphrased from the public 2004 edition: law.resource.org (PDF)
- IEC 60079-17, inspection and maintenance: inspection schedules for equipment suitability, group, temperature class and identification. Schedule items as reproduced in Moldovan et al., Annals of the University of Petrosani, Electrical Engineering 23 (2021): upet.ro (PDF)
- IECEx, FAQs from Ex equipment manufacturers, purchasers and users (online master certificates, status, issues, whom to contact): iecex.com
- European Commission, ATEX 2014/34/EU Guidelines, 6th edition (January 2026), marking, instructions and modification of approved types: single-market-economy.ec.europa.eu (PDF)
- US Coast Guard OCS National Center of Expertise, Drill Down 29 on certificates and what they contain: dco.uscg.mil
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.