Can Ex nA equipment still be installed now that Ex ec has replaced it?

Yes. Equipment certified and marked Ex nA still provides EPL Gc and is acceptable in Zone 2, both where it is already installed and when it is fitted from existing stock, provided its certificate, marking and instructions fit the application. A revision of the product standard does not make certified equipment unsafe or illegal to use; what changed is that new products are now assessed to IEC 60079-7 and marked Ex ec.

Short answer

• IEC 60079-7:2015 took over the non-sparking "nA" requirements from IEC 60079-15 as increased safety level ec (EPL Gc). IEC 60079-15:2017 no longer contains nA.
• Installed Ex nA equipment remains acceptable under the certificate it was supplied with, as long as it is inspected and maintained. There is no rule requiring replacement.
• Ex nA equipment from stock can be installed in Zone 2 if it was legally placed on the market and its marking (gas group, temperature class, ambient range, X conditions) suits the location.
• The current installation standard, IEC 60079-14:2024, still contains requirements for "nA" equipment, for example motors and terminations.
• New manufacture is a different matter: the manufacturer must show conformity with the current state of the art, which in practice means Ex ec.

Why a new standard does not cancel old equipment

Standards are revised to improve and clarify requirements, not to declare earlier equipment dangerous. The move from nA to ec was largely a change of home and name. The foreword of IEC 60079-7:2015 says the nA requirements were relocated into it, and that a product formerly marked nA needs the new ec marking even when its construction is unchanged and complies with the revised requirements.

Both are EPL Gc: suitable for Zone 2, where an explosive atmosphere is not expected in normal operation. Under the EU workplace directive 1999/92/EC, Zone 2 needs category 3 equipment or better, and an II 3 G Ex nA ... product meets that. Older equipment marked EEx nA from the EN 50021 era is also a Zone 2 product.

The installation standard confirms this approach. IEC 60079-14:2024, the current edition, keeps clauses headed for level "ec" and type of protection "nA" together, such as the requirements for electrical machines and for conductor terminations in "e" and "nA" equipment. An installer therefore applies the same rules to an nA motor as to an ec motor.

Installing Ex nA equipment from stock: what to check

Where the item is an Ex component (certificate number ending in "U"), it is not complete equipment and cannot be installed on its own; see the X and U suffixes.

What changes for manufacturers and buyers of new equipment

In Europe, EN 60079-15:2010, which still contained nA, was withdrawn in 2019 and replaced by EN IEC 60079-15:2019. A manufacturer who keeps building a product to a superseded standard must justify that it still meets the essential requirements and the state of the art. The coordination group of ATEX notified bodies set out this logic in a 2011 clarification sheet, written under the former Directive 94/9/EC: where a revision brings major technical changes, an existing certificate is not enough without an update. A certificate update has no retroactive effect on products already placed on the market or put into service.

For a buyer, the practical consequences are simple:

• New project specifications should ask for Ex ec (or any other EPL Gc or better concept), not Ex nA.
• Spares and replacements are normally supplied to the current standard and marking. An ec motor replacing an nA motor of the same rating is a like-for-like change in Zone 2 terms.
• Existing stock of nA items already bought may be used, after the checks above.
• National rules or company standards may be stricter, for example by requiring current-edition certificates for new installations. Follow them where they apply.

Common mistakes

• Rejecting installed Ex nA equipment at inspection only because the standard changed. Inspect it against its own certificate under IEC 60079-17.
• Using Ex nA in Zone 1 because "ec and eb are both increased safety". nA and ec are Gc only.
• Re-marking an nA product as ec on site. Only the manufacturer can do that, after assessment to IEC 60079-7.

Related on excodex

• Ex ec, Ex nA and Ex nR: protection for Zone 2
• The X and U suffixes on Ex certificates: specific conditions of use and Ex components
• Can Ex ec equipment be used in Zone 1?
• Has Ex nL been replaced by Ex ic?
• Tools: Ex marking check; standards spaces IEC 60079-7, IEC 60079-15, IEC 60079-14

Standards and further reading

• IEC 60079-7, equipment protection by increased safety "e", levels eb and ec (2015 with Amendment 1 of 2017).
• IEC 60079-15, equipment protection by type of protection "n" (2017, now only nC and nR).
• IEC 60079-14, design, selection and installation (edition 6, 2024).
• IEC 60079-17, inspection and maintenance of electrical installations.
• Directive 1999/92/EC, Annex II, Part B, equipment categories for each zone: legislation.gov.uk
• IEC 60079-7:2015 text, foreword on the relocation of nA and the ec marking: law.resource.org
• IEC 60079-14:2024 preview with contents and table of changes: standards.iteh.ai
• Status of EN 60079-15:2010 (withdrawn 2019): evs.ee
• ExNB clarification sheet ExNB/10/397/CS on certificates and the state of the art: PDF

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.