When a project engineer at a European industrial equipment manufacturer specified time delay relays for a new control panel, the manufacturer’s procurement team pushed back—”Do these meet IEC 61812-1?” Without the right certification documentation, the project stalled. The relay supplier claimed “CE compliance,” but CE marking without IEC 61812-1 testing meant nothing for time relay functional requirements.
This scenario plays out daily. IEC 61812-1 isn’t just a compliance checkbox—it’s the international framework that defines what “reliable time relay” means in measurable, testable terms. Engineers specifying components, procurement managers evaluating suppliers, and quality teams maintaining certification all face the same question: how do you know a time relay will perform as claimed? The standard provides the answer.
Three things make IEC 61812-1 matter: it establishes global performance baselines for timing accuracy and repeatability, verifies safety under electrical stress and environmental conditions, and provides a common language for comparing products across manufacturers. In the European market, it’s effectively mandatory for CE marking. Even in North America, where UL and NEMA frameworks dominate, IEC 61812-1 certification signals a manufacturer’s commitment to international quality benchmarks.
What Is IEC 61812-1? Overview and Purpose
IEC 61812-1 is the international standard titled “Time relays and coupling relays for industrial and residential use – Part 1: Requirements and tests.” Published by the International Electrotechnical Commission, it defines the performance, safety, and electromagnetic compatibility requirements for time delay relays used in control circuits, automation systems, and industrial equipment.
The standard’s current version is IEC 61812-1:2023 Edition 3.0, published in June 2023. This edition superseded the 2011 second edition and introduced significant updates including explicit coverage of coupling relays, cybersecurity requirements for industrial automation and control systems (IACS), environmental information mandates, and expanded routine testing protocols.
Think of IEC 61812-1 as the technical rulebook that answers: “What does a properly designed time relay look like?” It covers both electromechanical and solid-state relay technologies, addresses devices with DIN-rail mounting and plug-in socket configurations, and spans voltage ranges from low-voltage DC circuits to 240VAC industrial control applications.
The standard serves two audiences simultaneously. For manufacturers, it provides a structured testing and documentation framework that, once certified, opens global market access—particularly for EMEA, where it’s regionally adopted as EN IEC 61812-1:2024 and is effectively required for CE marking. For engineers and procurement professionals, it creates a common specification language; when a datasheet claims “IEC 61812-1 compliant,” you know exactly what that relay has been tested for and what performance documentation should exist.
Scope and Applicable Products: What the Standard Covers
IEC 61812-1 applies to time relays and coupling relays used in two broad application environments: industrial applications (control, automation, signal, and industrial equipment) and automatic electrical controls for residential and similar-use equipment. This dual scope makes the standard relevant whether you’re specifying relays for a factory automation panel or a residential HVAC control system.
What’s included: The standard covers all common time relay functions—on-delay (delay-on-energization), off-delay (delay-on-de-energization), interval timing, pulse output, flasher/cyclic operation, star-delta motor starting sequences, and multifunction programmable timing modes. It applies to both electromechanical relay outputs and solid-state switching outputs. Devices using voltage-dependent timing circuits, current-dependent timing, electronic timing circuits, pneumatic timing mechanisms, or hybrid technologies all fall within scope.
What’s excluded: Measuring relays are explicitly outside the standard’s scope. IEC 61812-1 focuses on functional time relays where timing is the primary control function, not relays that measure electrical parameters (voltage, current, frequency) and provide time-delayed responses based on measurement thresholds.
The standard defines device classifications across multiple dimensions: switching element type (electromechanical vs. solid-state), construction and housing type, mounting method (DIN-rail, plug-in socket, PCB mount, panel mount), connection method, and environmental suitability. This classification system ensures the requirements adapt to different relay technologies and installation scenarios rather than forcing a one-size-fits-all approach.
For procurement specifications, understanding scope matters when reading supplier datasheets. If a relay datasheet claims IEC 61812-1 compliance, you can expect documentation covering the device’s timing function type, classification category, rated operational parameters, and environmental limits—all defined within the standard’s framework.
Key Technical Requirements Explained
IEC 61812-1 structures its requirements into distinct categories, each addressing a specific aspect of relay performance, safety, or durability. These requirements translate into testable criteria that manufacturers must meet and engineers should look for in datasheets.
Classifications and Ratings
Every compliant relay must declare its classification and ratings, which define its operational boundaries. Rated input voltage and frequency specify the control voltage range at which the relay operates (e.g., 24VDC, 120VAC 50/60Hz, universal input 12-240VAC/DC). Release voltage defines the point below which the relay de-energizes, typically 10-20% of rated voltage. Power consumption indicates input power drawn by the timing circuit during operation.
Output circuit ratings vary by technology. Electromechanical outputs include contact ratings (voltage, current, load type) and mechanical/electrical endurance. Solid-state outputs specify switching voltage/current limits and leakage current. Conditional short-circuit current rating defines the maximum prospective short-circuit current the relay can handle when protected by a specified overcurrent device. Environmental ratings cover operating/storage/transport temperature ranges, humidity limits, pollution degree (I-IV per IEC 60664-1), and altitude rating.
Timing Performance Specifications
This is where IEC 61812-1 earns its relevance for time relays. The standard defines how timing accuracy must be measured and documented:
- Setting accuracy: The tolerance between the set timing value and the actual measured timing value at reference conditions (typically 23°C, rated voltage). Example: A 10-second timer with ±5% accuracy triggers between 9.5-10.5 seconds.
- Opakovatelnost: How consistently the relay hits the same timing value across multiple operations. Lower repeatability values mean more consistent performance.
- Recovery time: The minimum interval required between operations before the relay can accurately time again
- Minimum control impulse: The shortest pulse duration needed to reliably trigger timing
- Influence quantities: How timing performance degrades under varying voltage (±15% typical) and temperature extremes (operating range limits)
Annex A of the standard provides calculation methods for determining these values, which manufacturers use to generate the timing specifications you see in datasheets.
Safety and Dielectric Requirements
Electrical safety requirements ensure the relay won’t create shock hazards or fail catastrophically:
- Heating limits: Terminal and accessible surface temperatures must stay within defined limits during continuous operation and overload conditions. A ball pressure test verifies that plastic housings don’t deform under heat.
- Dielektrická pevnost: The relay must withstand power-frequency voltage tests (50/60Hz AC test voltage applied between isolated circuits) and impulse withstand voltage tests (1.2/50μs surge impulses simulating lightning or switching transients) without breakdown. Test levels are tabulated based on voltage rating and insulation category.
- Clearances and creepage distances: Physical spacing between conductive parts must meet minimum distances per IEC 60664-1, determined by working voltage, pollution degree, and insulation type.
- Ochrana před úrazem elektrickým proudem: Insulation systems must prevent access to hazardous live parts and maintain integrity under normal and fault conditions.
EMC and Environmental Requirements
Modern control panels operate in electrically noisy environments. IEC 61812-1 ensures time relays maintain performance despite electromagnetic interference:
- Immunity requirements: The relay must resist specified levels of conducted disturbances (voltage dips, surges, fast transients), radiated RF fields, electrostatic discharge, and magnetic fields without false triggering or timing errors. Separate tables define test levels for industrial environments vs. residential/light-industrial settings.
- Emitted disturbances: The relay’s switching and timing circuits must not generate excessive electromagnetic emissions that interfere with nearby equipment
- Vibration and shock: Mechanical robustness tests verify the relay maintains electrical continuity and timing accuracy under vibration (sinusoidal sweep, random vibration) and mechanical shock (half-sine pulse acceleration)
Edition 3.0 added cybersecurity requirements for relays connected to industrial automation networks (IACS environments) and environmental information mandates requiring manufacturers to document materials, recycling data, and environmentally conscious design processes.
Mechanical Strength and Endurance
Terminals, sockets, and mounting systems face mechanical stress during installation and operation:
- Terminal torque and pull-out tests: Screw terminals must withstand rated tightening torque without damage; wire pull-out tests verify retention
- Electrical endurance: Contacts (for electromechanical outputs) must complete a specified number of operations under different load types—resistive, inductive (with power factor), and low-energy DC loads. Solid-state outputs undergo equivalent switching cycle testing.
- Conditional short-circuit current tests: With a specified overcurrent protective device, the relay must survive prospective short-circuit conditions without creating fire or electric shock hazards
These requirements work together as a system. A time relay might have perfect timing accuracy in lab conditions but fail in the field if its EMC immunity is inadequate or its terminals loosen under vibration. IEC 61812-1’s comprehensive scope addresses the full operational reality.
Testing and Certification Procedures
IEC 61812-1 defines three test categories, each serving a different quality assurance purpose:
Type Tests verify design compliance. Manufacturers conduct these on representative samples to prove the product design meets all standard requirements. Type tests include the full battery: heating, basic operation at reference and influence conditions, timing accuracy and repeatability, dielectric strength, insulation resistance, clearances/creepage, electrical endurance, conditional short-circuit current, mechanical strength, EMC immunity and emissions, vibration, shock, glow-wire, and documentation completeness. Type testing is intensive—a single relay model may require weeks of lab time and dozens of samples.
Once type tests pass, the manufacturer doesn’t repeat them for every production unit. That’s where the other categories come in.
Routine Tests apply to 100% of production. Every single relay leaving the factory undergoes these abbreviated checks: basic functional operation (does it time correctly?), dielectric strength at reduced voltage (to catch insulation defects without damaging good units), and, for Edition 3.0, expanded routine checks including certain timing verification. Routine tests catch manufacturing defects without requiring the full type test program.
Sampling Tests sit between type and routine tests. Manufacturers periodically pull production samples and run a defined subset of tests to verify production consistency. This ongoing surveillance catches gradual drift in manufacturing processes before it creates field failures.
The standard also specifies marking and documentation requirements in Clause 8 and Table 7. Compliant relays must carry permanent markings including manufacturer identification, model/type designation, rated input voltage and frequency, output ratings, relevant standard references (IEC 61812-1), and CE marking where applicable. Technical documentation must provide all rated values, timing specifications (accuracy, repeatability, recovery time), environmental limits, connection diagrams, and installation instructions.
For certification in the European market, manufacturers typically work with notified bodies—accredited testing laboratories authorized to issue EU declarations of conformity. The process involves submitting technical files, providing samples for type testing, factory audits to verify production quality systems, and ongoing surveillance. Once certified, the manufacturer can affix the CE mark and issue an EU Declaration of Conformity for that product.
Buyers should understand that “IEC 61812-1 compliant” can mean different things depending on verification level. Full third-party certification (with notified body involvement) carries more weight than self-declared compliance with no independent test reports. When evaluating suppliers, ask to see test reports, not just claims.
IEC 61812-1 vs North American Standards (UL, NEMA)
Engineers working across North American and international markets often ask: “How does IEC 61812-1 relate to UL 508 or NEMA standards I’m familiar with?” The frameworks are complementary but address different levels of the product hierarchy.
IEC 61812-1 focuses specifically on functional requirements for time relays and coupling relays. It defines timing performance, classifications, environmental ratings, EMC, and application-level testing. Think of it as the “time relay functional specification standard.”
UL 61810-1 (formerly covered under UL 508) addresses electromechanical elementary relays at the component level. It verifies basic relay safety—insulation systems, contact ratings, temperature rise, endurance—independent of whether the relay has timing functions. If you’re using electromechanical time relays, both standards are relevant: UL 61810-1 ensures the underlying relay contacts and insulation are safe, while IEC 61812-1 verifies the timing circuit performs correctly.
UL 508A covers industrial control panels as complete assemblies. Time relays installed in UL 508A panels must meet component-level requirements (UL 61810-1 for electromechanical types, UL 508 Chapter 38 for solid-state devices), but the panel certification process is separate from relay certification.
NEMA IA 10039 (formerly NEMA ICS 5) provides application guidance, installation practices, and selection criteria for control-circuit and pilot devices, including time relays. It’s not a certification standard—it’s more like an application handbook. NEMA IA 10039 complements IEC 61812-1 by offering practical recommendations for relay selection, sizing, and installation that go beyond the IEC standard’s test requirements.
Practical implications: For EMEA projects, IEC 61812-1 certification is effectively mandatory; CE marking requires it. For North American projects, UL recognition (typically UL 508 or UL 61810-1) is the primary requirement, though IEC 61812-1 certification doesn’t hurt and may signal higher quality standards. Manufacturers serving global markets often pursue both IEC and UL certifications on the same product line. If you’re specifying for both markets, look for relays carrying both IEC 61812-1 and UL recognition—VIOX time delay relays, for example, maintain both certifications to serve global customers without requiring separate product lines.
Benefits of IEC 61812-1 Compliance
Beyond regulatory checkbox-ticking, IEC 61812-1 certification delivers tangible value to multiple stakeholders:
For manufacturers, it’s market access and competitive differentiation. EMEA markets effectively require EN IEC 61812-1:2024 for CE marking, so compliance unlocks European sales. The certification process also forces design discipline—products must meet defined performance benchmarks, not just “work well enough.” Manufacturers with IEC 61812-1 certification can credibly claim their timing accuracy, repeatability, and EMC performance have been independently verified.
For engineers specifying components, IEC compliance provides comparable performance data. When comparing time relays from different suppliers, IEC 61812-1 datasheets use standardized specifications measured under identical test conditions. Setting accuracy, repeatability, and influence-quantity performance become apples-to-apples comparisons rather than guesswork. You can specify “timing accuracy ±5% per IEC 61812-1” and know exactly what you’re getting.
For procurement and supply chain teams, certification reduces supplier qualification burden. A supplier claiming IEC 61812-1 compliance should have test reports, type test certificates, and declarations of conformity on file. Verifying compliance becomes a documentation check rather than requiring your own testing program. It also reduces risk—components failing IEC testing would likely cause field failures, warranty claims, and project delays costing far more than any upfront savings from non-certified alternatives.
For quality assurance and regulatory teams, IEC 61812-1 certification simplifies end-product compliance. If you’re building industrial control equipment requiring CE marking, using IEC-certified components streamlines your technical file preparation. The component’s test data becomes supporting evidence for your system-level compliance.
For system integrators and panel builders, certified components mean fewer surprises. Time relays meeting IEC EMC immunity requirements are less likely to false-trigger from VFD noise or nearby radio transmitters. Relays meeting IEC endurance and short-circuit requirements are less likely to fail prematurely in demanding applications. Fewer field callbacks translating directly to lower support costs and better reputation.
The standard also drives continuous improvement. Edition 3.0’s addition of cybersecurity and environmental information requirements reflects evolving industry needs. Manufacturers maintaining IEC certification must keep pace with these updates, ensuring their products stay relevant as industrial requirements advance.
How to Verify Supplier Compliance Claims
Not all “IEC 61812-1 compliant” claims are created equal. Here’s how to verify supplier claims without needing your own test lab:
Request the Declaration of Conformity (DoC). For CE-marked products sold in Europe, the manufacturer must provide an EU Declaration of Conformity stating which directives and harmonized standards the product meets. IEC 61812-1 (or EN IEC 61812-1:2024) should be explicitly listed. The DoC should include product identification, manufacturer details, and the name/signature of the person authorized to issue it. No DoC? Red flag.
Ask for test reports or certificates. Manufacturers who have actually conducted IEC 61812-1 testing possess test reports from accredited laboratories. These reports document which tests were performed, test conditions, results, and pass/fail status. Full test reports may be confidential, but summary certificates showing test scope and pass status should be available. If a supplier can’t produce any test documentation, their compliance claim is unsupported.
Check physical markings. IEC 61812-1 Clause 8 requires permanent markings on the relay itself. Look for the manufacturer’s mark, model/type designation, rated voltage and frequency, and the IEC 61812-1 reference. CE marks (for European market) should be visible and properly sized. Missing or incomplete markings suggest non-compliance or poor quality control.
Review datasheet completeness. IEC 61812-1 Table 7 lists required relay information. A compliant datasheet should document: timing function types, setting ranges, accuracy and repeatability values, rated input voltage/frequency, release voltage, output circuit ratings (contact type, voltage, current, endurance), environmental ratings (temperature, humidity, pollution degree), EMC environment suitability, and connection diagrams. Vague or missing specifications indicate the supplier either didn’t test or failed testing.
Verify notified body involvement (for CE marking). In Europe, certain product categories require third-party conformity assessment. While time relays typically allow self-certification under the Low Voltage Directive, manufacturers using notified bodies for voluntary certification demonstrate higher confidence. Ask if a notified body was involved and request their identification number.
Cross-check with similar products. If specifications seem too good to be true (±1% timing accuracy across -40°C to +85°C with no voltage influence, for example), they probably are. Compare claimed performance against established manufacturers’ datasheets for reality-checking.
Ask about Edition 3.0 updates. Since IEC 61812-1:2023 Edition 3.0 is the current version, ask whether the supplier’s certification is to the 2023 edition or the older 2011 edition. Edition 3.0 added cybersecurity and environmental requirements, so recent certification carries more weight.
When working with VIOX, customers receive complete documentation packages: EU Declaration of Conformity, type test reports from accredited laboratories, full datasheet specifications per Table 7, and product markings meeting Clause 8 requirements. Our certifications are maintained to the current Edition 3.0 standard, ensuring you’re specifying components tested to the latest requirements.
VIOX Time Delay Relays: IEC 61812-1 Certified
VIOX Electric maintains IEC 61812-1:2023 Edition 3.0 certification across our time relay product line, covering on-delay, off-delay, multifunction, and star-delta timing functions. Our certification scope includes both DIN-rail mounted and plug-in socket configurations, with voltage ranges from 12VDC to 240VAC.
Our certification process involves accredited third-party laboratories conducting full type testing per the standard’s requirements: timing accuracy and repeatability verification across temperature and voltage ranges, dielectric strength and insulation resistance testing, EMC immunity testing for industrial environments (per IEC 61812-1 Annex C industrial test levels), electrical endurance testing under resistive and inductive loads, and mechanical robustness verification including vibration and shock testing.
Every VIOX time relay ships with permanent markings per Clause 8, including IEC 61812-1 reference, CE marking (for European market), rated voltage and frequency, output contact ratings, and full model identification. Technical datasheets document all Table 7 required information, and customers receive EU Declarations of Conformity upon request.
For engineers specifying time relays for global projects, VIOX products carry both IEC 61812-1 and UL recognition, eliminating the need for separate component sourcing for EMEA and North American markets. Our compliance documentation streamlines your end-product certification process, whether you’re building control panels, automation systems, HVAC equipment, or industrial machinery.
Visit our product pages for detailed specifications, application notes, and compliance documentation for specific VIOX time relay models.
Conclusion: Standards Compliance as Quality Assurance
IEC 61812-1 represents more than a regulatory formality. It’s a structured framework that translates “this time relay works” into measurable, testable criteria covering timing performance, electrical safety, environmental robustness, and electromagnetic compatibility. For manufacturers, it’s a design and quality discipline. For specifiers, it’s a common language for comparing products. For procurement teams, it’s a verification tool that reduces supplier risk.
The 2023 Edition 3.0 keeps the standard relevant by adding cybersecurity and environmental requirements reflecting contemporary industrial priorities. As automation systems become more connected and sustainability pressures increase, these additions ensure IEC 61812-1 certification remains meaningful rather than becoming a legacy checkbox.
When evaluating time delay relays, don’t stop at “compliant” claims. Verify declarations of conformity, request test reports, check datasheet completeness, and inspect physical markings. The documentation trail matters as much as the certification itself—it’s your evidence that compliance is real, not just marketing language.
Standards compliance won’t prevent every field failure, but it stacks the odds in your favor. A relay tested to IEC 61812-1’s timing accuracy requirements is statistically more likely to perform reliably than an untested alternative. A relay meeting EMC immunity levels is less likely to false-trigger from electrical noise. A relay with documented endurance testing is less likely to fail prematurely under load. Compliance is insurance—you pay upfront (in component cost and specification effort) to reduce much larger downstream costs from failures, recalls, and reputation damage.
For your next project requiring time delay relays, make IEC 61812-1 certification a specification requirement, not an optional preference. The engineering work has already been done to define what “reliable” means. Use it.
