MCC Panels

PLC & Automation Control Panel — IEC 61439-2 (PSC)

IEC 61439-2 (PSC) compliance requirements, testing procedures, and design considerations for PLC & Automation Control Panel assemblies.

PLC & Automation Control Panel — IEC 61439-2 (PSC)

Overview

IEC 61439-2 applies to power switchgear and controlgear assemblies (PSC assemblies) that incorporate the control and distribution functions commonly found in PLC and automation control panels. For a PLC & Automation Control Panel, compliance is not achieved by selecting branded components alone; it is demonstrated by verified assembly design, appropriate internal separation, thermal performance, dielectric capability, short-circuit withstand, and routine production checks. Typical equipment integrated into these panels includes PLC CPUs and remote I/O, 24 VDC power supplies, relays, terminal blocks, signal conditioners, industrial Ethernet switches, MCCBs, MCBs, fused disconnects, motor starters, VFDs, soft starters, contactors, overload relays, and protection relays for feeder and motor circuits. Under IEC 61439-2, the manufacturer must complete design verification for each relevant characteristic of the assembly. This includes temperature-rise limits, dielectric properties, short-circuit withstand strength, protective circuit effectiveness, clearances and creepage distances, mechanical operation, degree of protection, and connection of external conductors. In practice, PLC panels often run mixed-load architectures, combining sensitive control electronics with motor feeders, which makes thermal management and EMC-oriented layout especially important. Design verification may be achieved by testing, comparison with a reference design, or assessment/calculation where permitted by the standard. Panels using VFDs or soft starters must also account for harmonics, heat dissipation, cable segregation, and filtering to avoid nuisance trips or premature component aging. Separation forms are a major design consideration. Depending on the application, Form 1 through Form 4 internal separation may be used to isolate functional units, busbars, and terminals, improving maintainability and reducing the risk of propagation faults. For high-availability automation systems, segregating control power, motor control, and communication networks can simplify maintenance and enhance service continuity. Rated operational current, busbar ratings, and short-circuit ratings must be declared and verified; common PSC assemblies may range from 63 A small machine panels to 1600 A or higher in process plants, with short-circuit withstand values often verified at 25 kA, 36 kA, 50 kA, or higher depending on the upstream network and protective devices. Documentation is a core compliance deliverable. A conforming PLC & Automation Control Panel should include a technical file, rating plate data, wiring diagrams, BOM, device datasheets, thermal calculations, and design verification records. Routine tests per IEC 61439-2 are typically performed on every manufactured assembly, including wiring continuity, insulation resistance, dielectric test where applicable, and functional checks of control circuits, interlocks, indications, and emergency stop chains. When the panel is intended for hazardous areas or harsh industrial environments, additional requirements may apply from IEC 60079 for explosive atmospheres and IEC 61641 for arc fault containment where arc-resistant performance is specified. For panel builders and EPC contractors, the compliance pathway begins with selecting a proven enclosure and component platform, then validating the assembly against the actual operating duty, environmental conditions, and fault levels. A well-engineered PLC automation panel compliant with IEC 61439-2 supports reliable operation in water treatment plants, packaging lines, food processing, utilities, building automation, and discrete manufacturing. Patrion’s engineering approach focuses on design verified, production-ready assemblies with clear certification evidence available on request, supporting project execution from concept through factory acceptance testing and site commissioning.

Key Features

  • IEC 61439-2 (PSC) 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
StandardIEC 61439-2 (PSC)
ComplianceDesign verified
CertificationAvailable on request

Other Standards for PLC & Automation Control Panel

EMC Compliance (IEC 61000)

Electromagnetic compatibility for sensitive environments

ATEX / IECEx Certification

Explosive atmosphere compliance for hazardous areas

IP Protection Ratings

Ingress protection classification (IP30–IP65+)

Other Panels Certified to IEC 61439-2 (PSC)

Main Distribution Board (MDB)

Primary power distribution from transformer to sub-circuits. Rated up to 6300A. Houses main incoming breaker, bus-section, and outgoing feeders.

Power Control Center (PCC)

High-capacity power distribution for industrial facilities. Controls and distributes incoming power to MCC, APFC, and downstream loads.

Motor Control Center (MCC)

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

Power Factor Correction Panel (APFC)

Automatic capacitor switching for reactive power compensation. Thyristor or contactor-switched, detuned or standard configurations.

Automatic Transfer Switch (ATS) Panel

Automatic changeover between mains and generator/UPS. Open or closed transition, with or without bypass.

Variable Frequency Drive (VFD) Panel

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

Generator Control Panel

Genset start/stop sequencing, synchronization, load sharing, and paralleling controls.

Metering & Monitoring Panel

Energy metering, power quality analysis, and multi-circuit monitoring with communication gateways.

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.

Harmonic Filter Panel

Active or passive harmonic filtering to mitigate THD from non-linear loads. Tuned LC filters, active filters, or hybrid configurations.

DC Distribution Panel

DC power distribution for battery systems, solar installations, telecom, and UPS applications. MCCB/fuse-based DC protection.

Capacitor Bank Panel

Fixed or automatic capacitor bank assemblies for bulk reactive power compensation in industrial and utility applications.

Frequently Asked Questions

IEC 61439-2 is the product standard for power switchgear and controlgear assemblies, and it is the correct compliance basis when a PLC panel includes power distribution, motor feeders, or other PSC functions. For PLC and automation panels, the standard requires design verification of temperature rise, dielectric strength, short-circuit withstand, protective circuit continuity, and internal separation where applicable. It also requires routine verification on each manufactured panel before delivery. In practice, this means the panel must be engineered as a verified assembly, not just built from compliant individual devices.
Certification or design verification under IEC 61439-2 is based on a defined set of characteristics, including temperature-rise limits, dielectric properties, short-circuit withstand strength, clearances and creepage distances, mechanical operation, degree of protection, and terminal connection suitability. Routine tests typically include wiring continuity, functional checks, and insulation resistance; dielectric testing is applied according to the verified design and manufacturer procedure. For panels with VFDs, soft starters, or high motor density, thermal verification is especially critical. The exact verification method may be testing, comparison with a reference design, or assessment/calculation, as permitted by the standard.
The short-circuit rating of an IEC 61439-2 PLC panel is determined by verifying that the assembly can withstand the prospective fault current at the point of installation. This involves assessing the busbar system, protective devices such as MCCBs or fuses, enclosure strength, and conductor arrangement. The declared rating may be based on tested data, a validated reference design, or calculation using manufacturer evidence. Common verified levels for industrial panels include 25 kA, 36 kA, and 50 kA, but the actual value must match the upstream fault level and protective coordination. The declared short-circuit withstand must appear in the panel documentation and rating label.
Yes. VFDs and soft starters introduce additional thermal load, harmonic distortion, and electromagnetic compatibility considerations that directly affect IEC 61439-2 design verification. The panel layout must provide adequate ventilation, spacing, and cable segregation so control electronics, PLC I/O, and communications remain reliable. Heat-generating devices may require forced ventilation, air conditioning, or derating of neighboring components. In addition, the selection of line reactors, EMC filters, shielding, and grounding strategy must be coordinated with the overall assembly design. These factors influence temperature-rise verification and long-term operational stability.
IEC 61439-2 allows different forms of internal separation, often referred to as Form 1 through Form 4, depending on the degree of isolation between busbars, functional units, and terminals. In PLC and automation control panels, separation is used to isolate control power, motor feeders, network equipment, and maintenance-accessible terminals. Higher forms of separation can improve safety, maintenance availability, and fault containment, particularly in continuous-process plants. However, the selected form must be consistent with the verified design, enclosure construction, and the manufacturer’s documented assembly method.
A compliant PLC and automation control panel should be supported by a technical file containing the single-line diagram, wiring schematics, bill of materials, device datasheets, enclosure data, thermal calculations, and the IEC 61439-2 design verification evidence. The panel should also have rating plate information showing rated current, rated voltage, frequency, short-circuit rating, degree of protection, and manufacturer identification. Routine test records should be retained for each assembly. For EPC projects, this documentation is essential for FAT, site acceptance, and future maintenance or retrofit work.
Often yes, but only if the existing panel can be re-engineered and re-verified as an assembly. Upgrades may involve replacing the enclosure, revising the internal layout, improving segregation, recalculating thermal performance, and validating the short-circuit rating against the installation fault level. Simply changing a PLC brand or adding relays does not create compliance. The panel builder must complete design verification and routine testing in line with IEC 61439-2. If the original construction data is incomplete, it is usually safer to rebuild the assembly using a verified design basis.
IEC 60079 applies when the panel is installed in or connected to hazardous areas where explosive atmospheres may be present, requiring appropriate protection concepts and certified equipment selection. IEC 61641 applies where arc fault containment or arc-resistant performance is specified for low-voltage controlgear assemblies. A PLC and automation control panel may need these additional standards if it is used in oil and gas, chemical processing, mining, or other high-risk industrial environments. In such cases, IEC 61439-2 remains the base assembly standard, but the design must also satisfy the relevant hazardous-area or arc-containment requirements.

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