ATEX and IECEx Panel Selection: How to Specify Electrical Equipment for Hazardous Areas in Europe

Executive Summary

Specifying electrical panels for hazardous areas in Europe is not just a procurement exercise. It is a compliance task that sits at the intersection of ATEX Directive 2014/34/EU, the IEC 60079 series, and site-specific hazardous area classification. For EU and EEA projects, ATEX is mandatory. For multinational projects, IECEx is often added to simplify export, spare parts, and maintenance across jurisdictions.

The practical challenge is that the panel must satisfy three things at once:

1. The zone and gas/dust group
2. The protection concept
3. The temperature class and installation method

If any one of those is wrong, the panel can fail factory acceptance, fail site inspection, or worse, become an ignition source. This guide explains how to specify an ATEX or IECEx panel with clause-level rigor, while still keeping the specification usable for contractors, panel builders, and automation teams.

1. The standards framework you actually need

1.1 ATEX and the EN/IEC 60079 family

ATEX is the legal framework in the EU, but the technical details come from harmonized EN standards based on IEC 60079. For panel specification, the most relevant documents are:

ATEX compliance is not just a label on the door. Under Directive 2014/34/EU, the manufacturer must maintain a technical file, risk assessment, and Declaration of Conformity. In practice, that means the panel spec must be traceable from zone classification all the way to the BOM.

1.2 IECEx and when dual certification makes sense

IECEx uses the same base standards, but the certification route is different. Instead of an EU Notified Body, the product is assessed by IECEx-accredited certification bodies and testing laboratories. The result is a published Certificate of Conformity on the IECEx system.

For a plant that only operates in Germany, France, or the Netherlands, ATEX alone is usually enough. For a company with plants in Europe, Australia, South Africa, and the Middle East, ATEX + IECEx is often the smarter procurement choice.

A practical rule:

• EU-only site - specify ATEX
• EU plus export or global spares - specify ATEX + IECEx

2. Start with hazardous area classification

Before you pick an enclosure, you need the site classification. Under IEC 60079-14, Section 5, the zone defines the probability of explosive atmosphere, while the group defines the gas or dust severity.

For gases, the group matters too:

For dust, the equivalent severity is often handled under the dust protection concepts in the IEC 60079 and legacy IEC 61241 families. In practice, if you have combustible dust, you must verify the enclosure is suitable for the dust zone and the dust layer temperature rise, not just the gas marking.

3. Choose the protection concept before choosing the hardware

The protection method determines what kind of panel you can build.

For most industrial panels, the decision is between Ex d, Ex e, and Ex p.

• Ex d is robust and familiar, but machining and maintenance are critical.
• Ex e is often used for terminals and non-sparking components.
• Ex p is attractive when heat dissipation is high, especially with PLCs, drives, and dense I/O.

Example marking

A panel marked:

II 2G Ex db IIB T4 Gb

means:

• Group II equipment for surface industries
• Category 2 for gas
• Flameproof enclosure
• Gas group IIB
• Temperature class T4
• Equipment Protection Level Gb

That marking is not decorative. It is the legal and technical summary of what the panel is allowed to do.

4. How to specify the enclosure correctly

4.1 Ex d enclosure requirements

For flameproof enclosures, EN/IEC 60079-1 is the key standard. The enclosure must be able to contain an internal explosion and cool escaping gases through the flame path.

Important design points include:

• Flame path length
• Joint geometry
• Fastener spacing
• Material thickness
• Pressure containment

A practical specification table might look like this:

The factory pressure test under IEC 60079-1, Annex B is the proof point. If the enclosure cannot survive the test, it cannot be used as a flameproof enclosure.

4.2 Ex e and terminal compartments

EN/IEC 60079-7 is used when the goal is to avoid arcs, sparks, and excessive temperatures. This is common for terminal blocks, control compartments, and some motor starters.

For Ex e assemblies, pay close attention to:

• Creepage and clearance distances
• Terminal temperature rise
• Component derating
• Conductor sizing
• Tightening torque

This is where many panels fail in the field. A technically good enclosure can still become non-compliant if a standard industrial relay or terminal block is substituted during procurement.

5. Temperature class is usually the hidden constraint

A panel can be perfectly sealed and still be unsafe if its surface temperature is too high.

Temperature class limits under EN/IEC 60079-0 are:

For industrial control panels, T4 is the most common target. T5 and T6 are possible, but they usually require lower internal dissipation or active thermal management.

A simple thermal check can be estimated as:

$$ T_{surface} = T_{ambient} + \Delta T $$

Where the ambient is often assumed to be 40°C unless the project says otherwise.

T_ambient = 40
delta_T = 5
T_surface = T_ambient + delta_T
T_surface

If the result is 45°C, the panel has a wide margin for T4, T5, and T6. But that is only a first-pass estimate. Real panels need component-by-component heat load review, especially if they include transformers, power supplies, or drives.

6. What goes inside the panel matters as much as the enclosure

A common mistake is to buy a certified enclosure and then fill it with non-certified components. That defeats the purpose.

6.1 Component selection rules

For example, if you are using a Siemens S7 PLC or Rockwell ControlLogix I/O inside a pressurized cabinet, the PLC hardware itself may be standard industrial equipment, but the cabinet protection concept must keep the enclosure compliant. In contrast, a Siemens Sinamics or ABB ACS drive often drives the thermal and pressurization design more than the PLC does.

6.2 Automation platform choices inside hazardous-area architectures

The control platform usually stays outside the hazardous area, but the architecture still matters. Common platforms include:

• Siemens S7
• Rockwell ControlLogix
• Schneider Modicon
• Beckhoff TwinCAT
• Ignition
• AVEVA System Platform
• COPA-DATA zenon

For SCADA and PLC integration, the safest pattern is often:

• Field devices in Zone 0 or 1 use Ex i or suitable junction boxes
• Local marshalling in Ex e or Ex d cabinets
• PLCs and SCADA servers located in a safe area or protected control room

That separation reduces certification burden and simplifies maintenance.

7. Example specification logic for a Zone 1 gas area

Suppose you are specifying a control panel for an ethylene process area in Europe.

Project assumptions

• Gas group: IIB
• Zone: 1
• Ambient: 40°C
• Internal load: moderate
• Maintenance access: frequent
• Future expansion: likely

A sensible approach is often Ex de or Ex p, depending on the heat load.

If the panel includes only a disconnect, contactor, relays, and terminals, Ex d is often enough. If it includes a high-density PLC cabinet with network switches, remote I/O, and a UPS, Ex p or relocating the electronics outside the zone is usually better.

8. Procurement checklist for engineers and contractors

A good specification should force the supplier to prove compliance. Use a checklist like this:

8.1 Before purchase

1. Confirm zone, gas group, and ambient temperature.
2. Define required protection concept.
3. State required ATEX category and EPL.
4. Require IECEx certificate if dual certification is needed.
5. Require thermal calculation and worst-case dissipation.
6. Require factory test records.

8.2 In the technical schedule

8.3 Installation and inspection

Under IEC 60079-14 and IEC 60079-17, the site team must verify:

• Correct gland type and tightening
• Earthing and bonding continuity
• No unauthorized field modifications
• Correct torque on flameproof joints
• Inspection intervals and records

If you are using a contractor, specify that the installation must be signed off by personnel competent in hazardous area work. In Europe, that is not a nice-to-have. It is a project risk control.

9. ATEX only or ATEX plus IECEx?

Here is a practical decision matrix.

If the plant is a one-country European asset, ATEX is usually enough. If the owner has a standard global panel design, dual certification often pays for itself through reuse, fewer redesigns, and simpler spare parts management.

10. Common mistakes that cause non-compliance

A panel can look perfect and still fail audit if the BOM does not match the certificate. That is why the drawing package, test record, and final as-built BOM must stay synchronized.

11. A practical specification statement you can reuse

A concise engineering specification might read:

Supply a hazardous-area electrical control panel for Zone 1, gas group IIB, ambient 40°C, with ATEX 2014/34/EU compliance and IECEx certification where available. Panel shall be Ex d or Ex de as required by internal heat load, with final temperature class not exceeding T4. All internal components, cable glands, and accessories shall be certified or suitable for the selected protection concept. Supplier shall provide technical file extracts, test reports, certificate numbers, and installation instructions in accordance with EN/IEC 60079-0, -1, -7, -14, and -17.

That one paragraph forces the supplier to think about the full compliance chain, not just the enclosure.

Conclusion

Selecting electrical equipment for hazardous areas in Europe is mostly about disciplined specification. Start with the zone, group, and ambient conditions. Choose the protection concept before choosing the brand. Verify the temperature class against real heat load. Then make sure every internal component, gland, and accessory supports the same certification logic.

For many projects, the best answer is not a more complicated panel. It is a better architecture: keep high-power and high-density electronics out of the hazardous zone, use certified field interfaces where needed, and reserve Ex d or Ex p panels for the cases where they are truly justified.

If you are planning an ATEX or IECEx panel and want help translating a process hazard study into a buildable electrical specification, we can help you define the right enclosure, component list, and compliance path - /contact