MCC Panels

PLC & Automation Control Panel — ATEX / IECEx Certification

ATEX / IECEx Certification compliance requirements, testing procedures, and design considerations for PLC & Automation Control Panel assemblies.

PLC & Automation Control Panel — ATEX / IECEx Certification

Overview

ATEX / IECEx certification for PLC and Automation Control Panels is fundamentally about ensuring that electrical equipment can be safely installed and operated in hazardous atmospheres without becoming an ignition source. For panel assemblies used in Zone 1, Zone 2, Zone 21, or Zone 22 applications, the design basis must be aligned with the applicable equipment protection concepts such as Ex e, Ex i, Ex p, Ex d, Ex n, or Ex t, depending on the installation philosophy and the hazardous area classification. In practice, this means the control panel enclosure, internal wiring, terminals, power supply architecture, instrument barriers, and heat dissipation strategy must be engineered as a certified system rather than as a conventional industrial cabinet with added components. A compliant PLC & Automation Control Panel typically integrates PLC CPUs, remote I/O, managed industrial Ethernet switches, HMI terminals, power supplies, intrinsic safety barriers, isolators, relays, safety relays, and sometimes VFDs or soft starters for field equipment. The selection of these devices must consider their EPL, gas group, temperature class, and T-code limits. For example, a VFD or soft starter may require placement in a purged Ex p enclosure or outside the hazardous area due to thermal loading, switching losses, and surface temperature rise. Similarly, ordinary components such as ACBs, MCCBs, contactors, and SMPS units may be acceptable only when their installation context, creepage and clearance distances, and maximum dissipation are controlled by the certified assembly design. IEC 60079 series requirements govern explosive atmosphere design, with IEC 60079-0 for general requirements and the relevant part depending on the protection type. For enclosure-based compliance, IEC 60079-7, IEC 60079-11, IEC 60079-2, and IEC 60079-31 are frequently applicable. The panel as an assembly may also require verification against IEC 61439-1 and IEC 61439-2 or IEC 61439-3 when low-voltage switchgear and controlgear elements are incorporated, especially where power distribution or motor control is included. If the enclosure is part of a functional safety or process shutdown architecture, the design may also interface with IEC 61508 or IEC 61511 system requirements, while EMC performance and segregation must be controlled in accordance with IEC 61326 and good industrial practice. Design verification for ATEX / IECEx compliance includes temperature rise evaluation, ingress protection validation, fault-current withstand analysis, verification of wiring segregation, terminal suitability, earthing and bonding continuity, and checks on component derating under worst-case ambient conditions. Short-circuit ratings must be clearly established, especially where MCCBs, fuse disconnects, or distribution feeders are used inside the enclosure. For purged or pressurized panels, leakage testing, purge flow checks, pressure decay verification, and alarm/interlock functionality are key acceptance tests. For increased safety and intrinsic safety solutions, spacing, field wiring identification, energy limitation, and entity parameter matching are critical. Documentation is a major part of the certification pathway. A compliant package normally includes a technical file, risk assessment, hazardous area classification basis, enclosure drawings, wiring schematics, BOM with certified component references, thermal calculations, routine inspection records, and traceability of IECEx or ATEX-certified devices. Manufacturers often need evidence of type testing, routine production testing, and certificate control for any replacement parts used during maintenance. Ongoing compliance is equally important because a field modification, cable entry change, or component substitution can invalidate the certification basis. For EPC contractors, integrators, and facility managers, the safest approach is to specify a panel manufacturer experienced in hazardous-area assemblies, with verified workmanship, disciplined documentation, and certified component selection from trusted suppliers.

Key Features

  • ATEX / IECEx Certification compliance pathway for PLC & Automation Control Panel
  • Design verification and testing requirements
  • Documentation and certification procedures
  • Component selection for standard compliance
  • Ongoing compliance maintenance and re-certification

Specifications

PropertyValue
Panel TypePLC & Automation Control Panel
StandardATEX / IECEx Certification
ComplianceDesign verified
CertificationAvailable on request

Other Standards for PLC & Automation Control Panel

IEC 61439-2 (PSC)

Power switchgear and controlgear assemblies — main compliance standard

EMC Compliance (IEC 61000)

Electromagnetic compatibility for sensitive environments

IP Protection Ratings

Ingress protection classification (IP30–IP65+)

Other Panels Certified to ATEX / IECEx Certification

Motor Control Center (MCC)

Centralized motor control with starters, contactors, overloads, and VFDs in standardized withdrawable/fixed functional units.

Variable Frequency Drive (VFD) Panel

Enclosed VFD assemblies with input protection, line reactors, EMC filters, output reactors, and bypass options.

Custom Engineered Panel

Bespoke panel assemblies for non-standard requirements — special ratings, unusual form factors, multi-function combinations.

Soft Starter Panel

Enclosed soft starter assemblies for reduced voltage motor starting with torque control, ramp-up/down profiles, and bypass contactor options.

Frequently Asked Questions

A compliant hazardous-area control panel normally requires a complete technical file rather than a single certificate. At minimum, this includes the hazardous area classification basis, explosion protection concept, general arrangement drawings, wiring schematics, bill of materials with certified Ex component references, temperature rise calculations, ingress protection evidence, earthing/bonding details, and routine test records. Depending on the protection method, supporting documentation may also include purge/pressurization test logs, intrinsic safety entity parameter calculations, or enclosure strength verification. IEC 60079-0 and the relevant part of IEC 60079-7, -11, -2, or -31 are commonly referenced, while IECEx certification often requires traceability to the relevant ExTR and QAR processes. For integrated power sections, IEC 61439 verification documents are also commonly needed.
Yes, but only if the thermal and ignition-risk implications are addressed in the certified design. VFDs and soft starters generate heat and can create unsuitable surface temperatures in Zone 1, Zone 2, or dust zones unless they are installed in a suitable protection concept such as Ex p purge, a suitably certified Ex enclosure, or outside the hazardous area with appropriately protected field wiring. The design must verify temperature class, component derating, ventilation or purge performance, and fault behavior. In many projects, the safer approach is to keep power conversion equipment outside the hazardous area while placing only the PLC, I/O, barriers, and low-energy control devices within the Ex-certified panel. IEC 60079-0 and the applicable substandard govern the installation method, while the power distribution section may still need IEC 61439 verification.
ATEX is the European regulatory framework for equipment used in explosive atmospheres, while IECEx is an international certification scheme based on IEC standards. For a PLC & Automation Control Panel, both systems rely heavily on IEC 60079 requirements, but the administrative pathways differ. ATEX generally requires conformity to the relevant EU directives, CE marking, and an EU declaration of conformity, whereas IECEx focuses on internationally recognized test reports, certificates, and ongoing quality surveillance. In practice, many manufacturers design one panel platform to satisfy both pathways, using certified components and documented design verification. For export projects, IECEx can simplify acceptance in multiple countries, while ATEX is necessary for installations within the EU where the directive applies. The engineering content of the panel, however, is often very similar.
The best protection concept depends on the equipment mix, heat load, and maintenance philosophy. For many Zone 2 PLC and automation panels, Ex nR, Ex ec, or Ex p are common strategies, but the final choice must be based on the certified product category, the internal component temperatures, and the expected intervention level. If the panel contains only low-energy controls, barriers, and PLC hardware, an Ex ec or suitable increased-safety solution may be practical. If it contains higher dissipation devices or frequent operator access, pressurization/purging may provide greater flexibility. The selection should always consider cable entries, field wiring segregation, and environmental factors such as ambient temperature and dust ingress. IEC 60079-7, IEC 60079-2, and IEC 60079-31 are often relevant depending on the exact concept and area classification.
Intrinsic safety barriers and isolators limit energy to field instruments so that ignition cannot occur even under fault conditions. In PLC & Automation Control Panels, they are typically used for transmitters, switches, and low-power sensors located in hazardous zones. The design must verify entity parameters such as voltage, current, capacitance, and inductance, ensuring the barrier output matches the field device and cable characteristics. Barriers should be mounted with clear segregation from non-IS circuits, with dedicated terminals, labeling, and earthing arrangements where required. IEC 60079-11 governs intrinsic safety, and the panel documentation should show the cable length assumptions and approved combinations. Good panel design also prevents accidental cross-wiring during maintenance, which is a common compliance risk in plant environments.
Pre-shipment testing usually includes visual inspection, continuity checks, insulation resistance, functional checks, terminal torque verification, verification of protective earth bonding, and validation of all Ex-specific design features. If the panel uses Ex p purge, then purge timing, pressure decay, alarm, and interlock tests are performed. For dust protection, enclosure sealing, cable gland suitability, and surface cleanliness are checked carefully. Any power distribution section may also undergo routine dielectric and operational testing consistent with IEC 61439 practices. The exact routine tests depend on the protection concept and the certified assembly design, but the objective is always the same: confirm that the manufactured panel matches the certified configuration and that no workmanship issue could compromise the explosion protection system.
Only if the replacement is functionally and certification-equivalent within the approved design envelope. In hazardous-area panels, replacing a component with a non-equivalent part can invalidate the compliance basis if it changes temperature rise, creepage and clearance, enclosure rating, or Ex certification status. For example, substituting a power supply, HMI, relay, gland, or terminal block requires confirmation that the new item has the same or better Ex rating, ambient limits, and electrical characteristics. Many operators maintain a controlled approved parts list to preserve certification integrity. Any modification beyond that list should be reviewed by the manufacturer or a competent Ex engineer, and in some cases re-assessment or recertification will be necessary. Maintaining traceability is essential for auditability and plant safety.
Separation inside an Ex-rated PLC panel depends on the protection concept and the circuit types present. Typically, segregation is required between intrinsic safety circuits and non-IS circuits, between SELV/PELV control circuits and power circuits, and between hazardous and non-hazardous field terminations. Physical segregation may be achieved with barriers, partitions, separate wiring ducts, dedicated terminal rows, or separate compartments. For combined automation and distribution panels, power sections with MCCBs, ACBs, or motor feeders are often isolated from PLC and communications hardware to reduce heat and fault propagation. IEC 60079-14 and the relevant parts of IEC 60079-11, -7, or -31 guide the separation rules, while IEC 61439 governs internal partitioning, form of separation, and short-circuit withstand for the low-voltage switchgear portion of the assembly.

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