IECEx vs ATEX vs NEC 500: which certificate your site actually needs

The question of IECEx vs ATEX comes up in almost every hazardous area equipment tender, usually in the form of a supplier holding one of them and a buyer needing the other. Add the North American system, where the National Electrical Code governs and neither of the first two counts, and you have three parallel worlds describing identical physics in different documents.

They are not interchangeable, and the places where they stop recognising each other are the places where procurement schedules slip. This guide sets out what each system is, what a certificate and its schedule actually contain, how to read a marking string, and which system a buyer needs in which country.

One set of physics, three sets of paperwork

All three systems rest on the same technical foundation: the IEC 60079 series. IEC 60079-0 sets the general requirements for equipment, IEC 60079-11 governs intrinsic safety, IEC 60079-1 flameproof enclosures, IEC 60079-7 increased safety, and so on through the series. IEC 60079-10-1 and IEC 60079-10-2 cover the classification of gas and dust areas, IEC 60079-14 covers the design and selection of installations, IEC 60079-17 inspection and maintenance, and IEC 60079-19 repair and overhaul.

Europe adopts those documents as the EN 60079 series. North America adopts large parts of them as the UL and CSA 60079 series alongside its own older standards. Australia and New Zealand adopt them as the AS/NZS 60079 series. The technical requirements a manufacturer must meet are therefore close to identical everywhere. What differs is who issues the paper, what legal weight it carries, and whether anyone else will accept it.

IECEx: the international scheme

IECEx is a voluntary international certification system operated under the IEC. Its equipment arm, run under the rules in IECEx 02, is the Certified Equipment Scheme, and its output is an IECEx Certificate of Conformity, usually written CoC.

The mechanics matter when you are reading one. An IECEx CoC is issued by an accepted certification body, an ExCB, on the basis of two things: an Ex Test Report (ExTR) recording that the product meets the relevant parts of IEC 60079, and a Quality Assessment Report (QAR) recording that the manufacturer’s production quality system has been audited and can reproduce the tested sample. A test result on its own does not get you a certificate. Since it began in the 1990s the scheme has grown to more than sixty accepted certification bodies across more than thirty-five countries, plus a longer list of countries that accept an IECEx CoC without being participating members.

Two features are unusually useful to a buyer. First, every certificate is published in a public online certificate system, so the master version of the document is the one on the IECEx site rather than the PDF a supplier emails you. Second, the scheme extends beyond equipment: there is a certified service facility scheme for repair and overhaul workshops, and a personnel competence scheme for the people who install and inspect Ex equipment.

The limitation is equally important. IECEx is not a market access mark. Holding an IECEx CoC does not make a product legal to place on the European market, and does not satisfy an American electrical inspector. It is the technical evidence that the national and regional systems are built on.

ATEX: the European legal route

ATEX is a pair of European directives, and people routinely conflate them. Directive 2014/34/EU is the equipment directive, addressed to manufacturers, and it is the one that produces certificates and CE marking. Directive 1999/92/EC is the workplace directive, addressed to employers, and it is the one that requires an employer to classify areas into zones and produce an explosion protection document. In Great Britain the workplace side is implemented through DSEAR, the Dangerous Substances and Explosive Atmospheres Regulations 2002.

Under 2014/34/EU, equipment is sorted into groups and categories. Group I is mining, with categories M1 and M2. Group II is everything else, with categories 1, 2 and 3, which correspond to Zone 0, Zone 1 and Zone 2 for gas and Zone 20, Zone 21 and Zone 22 for dust. The category drives the conformity assessment route. For Category 2 electrical equipment, which is the Zone 1 case and therefore the one that covers a hazardous area handset, the manufacturer needs an EU-type examination by a notified body, followed by a production-phase module in which the notified body assesses and monitors the quality system. Self-declaration is not available at this category, and a supplier offering a self-declared CE mark for Category 2 equipment is offering something the directive does not permit.

The visible outputs are an EU-type examination certificate from a named notified body, an EU declaration of conformity signed by the manufacturer, and a product label carrying the CE mark, the four-digit identification number of the notified body involved in production surveillance, the specific marking of explosion protection, and the full marking string.

The UK position after Brexit

Great Britain runs its own version through the Equipment and Protective Systems Intended for Use in Potentially Explosive Atmospheres Regulations 2016, with UK approved bodies issuing UK-type examination certificates and the product carrying UKCA marking. This route is often called UKEX. Crucially, the UK government has extended recognition of CE marking for placing these products on the GB market indefinitely, given effect by the Product Safety and Metrology (Amendment) Regulations 2024, which came into force on 1 October 2024. Northern Ireland continues to follow the EU rules. For a buyer this means a CE-marked ATEX product remains placeable in Great Britain, while a UKCA route exists for suppliers who want it. The UK market page sets out what this means for device procurement in practice.

NEC 500, 505 and 506: the North American route

In the United States the governing document is NFPA 70, the National Electrical Code, and the relevant articles are grouped by classification system.

• Article 500 establishes the traditional Class and Division system, with Articles 501, 502 and 503 covering Class I gases and vapours, Class II combustible dusts, and Class III fibres and flyings.
• Article 504 covers intrinsically safe systems, including the requirement that installation follows the control drawing for the system.
• Article 505 provides the Zone system as an alternative for Class I locations, using Zones 0, 1 and 2 aligned with the IEC concept.
• Article 506 does the same for combustible dusts and ignitable fibres and flyings, using Zones 20, 21 and 22.

Two features separate this system from the other two. The first is the meaning of approval. NEC-governed equipment must be listed for the classified location by a nationally recognised testing laboratory, an NRTL under the OSHA scheme. A manufacturer’s own declaration has no standing. The second is the grouping. North America splits Class I gases into Groups A, B, C and D, roughly acetylene, hydrogen, ethylene and propane, where the IEC uses IIC, IIB and IIA. Class II dusts are Groups E, F and G.

Markings differ accordingly. A Division-system label reads along the lines of Class I, Division 1, Groups C, D, T4. A Zone-system label under Article 505 uses the AEx prefix and looks much more familiar to an IEC reader: Class I, Zone 1, AEx ib IIC T4 Gb.

Where mutual recognition stops

This is the section worth reading twice, because it is where programmes lose months.

IECEx does not become ATEX by itself. An IECEx certificate is not sufficient to place a product on the EU market; a separate EU-type examination is required. What does travel is the test report. An ExTR can be used as the technical basis for an ATEX EU-type examination certificate, and because many notified bodies are also IECEx certification bodies, the same organisation frequently issues both from one body of testing. The relationship does not run the other way: an ATEX certificate cannot be used as the basis for an ExTR.

Neither becomes a NEC listing. There is no route by which an IECEx CoC or an ATEX certificate directly authorises equipment for a US classified location. The product has to be listed by an NRTL. Within the NEC itself there is limited cross-acceptance between its own two systems: equipment listed and marked for use in Zone 0, 1 or 2 under Article 505 is permitted in Class I Division 2 locations for the same gas and a suitable temperature class. Division 1 locations are not covered by that allowance, which is why a manufacturer targeting Zone 1 in Europe still needs a distinct programme to answer a Class I Division 1 phone requirement in Texas or Alberta.

Australia and New Zealand are the friendly case. The AS/NZS 60079 series is harmonised with IEC 60079, and both IECEx certificates and national ANZEx certificates are accepted for equipment in hazardous areas in almost all cases. See the Australia market page for how that plays out on mine sites and LNG facilities.

National overlays sit on top of all of it. Saudi Arabia routes products through SASO conformity and the SABER platform, with the IECEx certificate as the underlying technical evidence. India requires approval from the Petroleum and Explosives Safety Organisation for equipment used in licensed premises. Nigeria operates a conformity assessment programme for imports alongside local content requirements. None of these replaces the Ex certificate; all of them add a step. The market pages for Saudi Arabia, the UAE, India and Nigeria cover the local mechanics.

Radio approval is a separate track entirely. An ATEX mobile phone is still a radio transmitter. It needs conformity with the Radio Equipment Directive 2014/53/EU in the EU, the equivalent UK regulations in Great Britain, an FCC identifier in the United States, and national type approval in many other markets. The Ex certificate says nothing about any of that, and a device can be perfectly certified for Zone 1 and still illegal to switch on.

What a certificate schedule contains

Buyers often ask for “the certificate” and receive a single cover page. The cover page is the least informative part. What you want is the certificate together with its schedule, which is where the substance lives.

The cover page typically carries the certificate number and its status, the certificate holder and the manufacturing locations, a short equipment description, the standards and editions applied, the full marking, the issuing body and the signatory, and the issue date. The schedule then carries the detail: the specific models and variants covered, including suffixes and configuration codes; electrical parameters and, for battery equipment, the specific cell types permitted; the specific conditions of use; a list of the controlled drawings and documents that define the certified construction; and any routine tests the manufacturer must perform on every unit.

Two suffixes on the certificate number change how you read the whole document. An X means there are specific conditions of use, and you must read them, because they are the difference between compliant and non-compliant use in the field. For portable electronics these commonly cover charging location, permitted battery types, electrostatic precautions and cleaning. A U means the certificate covers an Ex component rather than a finished product, such as an enclosure or a terminal block. A U-marked certificate can never be the certificate for a phone, and if one is offered as such, something is wrong.

How to read a marking string

So II 2 G Ex ib IIC T4 Gb reads as: surface equipment, Zone 1 category, gas atmosphere, intrinsically safe at the two-fault level, suitable for the most demanding gas group, maximum surface temperature 135 °C, equipment protection level Gb. Beside it you should find the ambient temperature range, which is a genuine limit rather than a formality, and the IP rating.

Which system a buyer needs, by market

A useful rule of thumb for a global operator: specify the IECEx certificate as the technical baseline in every tender, then add the local instrument on top. That gives you one comparable document across every site, and it is the document that most national schemes will read anyway.

Where SAMS is in that process

The SAMS IS-04Z1 is pre-launch, with a Q4 2026 launch and IECEx, ATEX and NEC 500 Class I Division 1 programmes all in progress rather than complete. The honest thing a buyer can ask for at this stage is the certification schedule: which scheme, which body, which standards, and what the target dates are. When the certificates are issued, they will be verifiable in the usual way, which is the subject of a separate guide in our insights library.

Frequently asked questions

Official sources

• IECEx scheme
• IEC hazardous areas (Ex) overview
• European Commission: ATEX equipment
• Directive 2014/34/EU (EUR-Lex)
• HSE: equipment for explosive atmospheres
• OSHA 29 CFR 1910.307
• NFPA 70 (National Electrical Code)