IEC (International Electrotechnical Commission) Standards

The International Electrotechnical Commission (IEC) is the world's leading organization for the preparation and publication of international standards for electrical, electronic, and related technologies. Founded in 1906, the IEC brings together experts from national committees in over 170 countries to develop consensus-based standards that ensure safety, performance, and interoperability of electrotechnical products worldwide.

IEC standards form the technical foundation for product safety regulations in most countries. Regulatory authorities frequently adopt IEC standards by reference, making compliance with these standards a practical requirement for market access. The CB Scheme, administered by the IEC, facilitates international recognition of test results, enabling manufacturers to obtain certifications in multiple markets based on a single test report.

This article provides comprehensive coverage of the major IEC standards families relevant to electronics professionals, including their scope, key requirements, and practical implementation guidance.

IEC 60601: Medical Electrical Equipment

IEC 60601 is the cornerstone standard for medical electrical equipment safety, recognized by regulatory authorities worldwide including the FDA, European notified bodies, and health agencies throughout Asia and the Americas. The standard series comprises a general standard (IEC 60601-1) and numerous particular standards addressing specific types of medical equipment.

IEC 60601-1: General Requirements

The general standard establishes fundamental safety and essential performance requirements for all medical electrical equipment. Key areas addressed include:

Classification: Equipment is classified by protection class (Class I, II, or internally powered), type of protection against electric shock (Type B, BF, or CF applied parts), and mode of operation
Protection against electrical hazards: Requirements for insulation, protective earthing, leakage currents, and dielectric strength ensure patients and operators are protected from electric shock
Protection against mechanical hazards: Standards for enclosure strength, stability, moving parts, and surfaces address physical safety
Protection against hazards from unwanted radiation: Limits on X-ray, microwave, and other radiation emissions protect users from exposure
Essential performance: The standard requires identification and verification of functions whose failure could result in unacceptable risk
Programmable electrical medical systems (PEMS): Requirements for software-controlled equipment ensure safe operation under normal and fault conditions

Collateral Standards (IEC 60601-1-x)

Collateral standards provide additional requirements that apply broadly across medical equipment types:

IEC 60601-1-2: Electromagnetic disturbances requirements and tests, ensuring medical equipment operates safely in the electromagnetic environment and does not interfere with other equipment
IEC 60601-1-6: Usability engineering requirements, addressing human factors to prevent use errors that could harm patients
IEC 60601-1-8: Alarm systems requirements for medical equipment, standardizing alarm signals to improve operator response
IEC 60601-1-9: Environmentally conscious design, addressing sustainability throughout the product lifecycle
IEC 60601-1-10: Physiologic closed-loop controllers, covering automated feedback systems
IEC 60601-1-11: Home healthcare environment requirements, addressing the unique risks of medical equipment used outside clinical settings
IEC 60601-1-12: Emergency medical services environment, covering equipment used in ambulances and similar settings

Particular Standards (IEC 60601-2-x)

Particular standards modify or add to the general requirements for specific equipment types. Examples include:

IEC 60601-2-1: Electron accelerators for radiotherapy
IEC 60601-2-2: High frequency surgical equipment
IEC 60601-2-4: Defibrillators
IEC 60601-2-12: Lung ventilators
IEC 60601-2-13: Anesthesia workstations
IEC 60601-2-16: Hemodialysis equipment
IEC 60601-2-25: Electrocardiographs
IEC 60601-2-27: Electrocardiographic monitoring equipment
IEC 60601-2-34: Invasive blood pressure monitoring
IEC 60601-2-37: Ultrasonic medical diagnostic equipment
IEC 60601-2-44: X-ray equipment for computed tomography
IEC 60601-2-45: Mammographic X-ray equipment
IEC 60601-2-49: Multifunction patient monitoring equipment
IEC 60601-2-52: Medical beds

Implementation Considerations

Successfully implementing IEC 60601 requires understanding that the standard takes a risk-based approach. Manufacturers must conduct risk analysis per ISO 14971 and document how identified hazards are addressed. Testing must be performed by accredited laboratories, and comprehensive documentation is required for regulatory submissions.

IEC 61010: Measurement, Control, and Laboratory Equipment

IEC 61010 establishes safety requirements for electrical equipment intended for measurement, control, and laboratory use. This includes test and measurement instruments, industrial process measurement equipment, and laboratory apparatus used in educational, commercial, and industrial settings.

IEC 61010-1: General Requirements

The base standard addresses hazards that may be encountered during normal operation, reasonably foreseeable misuse, and fault conditions. Key requirements include:

Measurement categories (CAT I-IV): Equipment is rated by the installation category where it will be used, from protected circuits (CAT I) to service entrance equipment (CAT IV)
Overvoltage protection: Requirements for transient overvoltage withstand capability vary by measurement category
Protection against electric shock: Similar to IEC 60601, the standard requires proper insulation, earthing, and current limiting
Mechanical hazards: Requirements for stability, sharp edges, and moving parts
Chemical hazards: Provisions for equipment that may release hazardous substances
Temperature limits: Maximum surface temperatures to prevent burns

Particular Standards in the Series

IEC 61010-2-010: Laboratory equipment for heating materials
IEC 61010-2-020: Laboratory centrifuges
IEC 61010-2-030: Equipment with testing or measuring circuits
IEC 61010-2-032: Hand-held current clamps for electrical measurement
IEC 61010-2-033: Multimeters for domestic and professional use
IEC 61010-2-034: Measurement equipment for insulation resistance and test equipment for withstand voltage
IEC 61010-2-040: Sterilizers
IEC 61010-2-051: Laboratory equipment for mixing and stirring
IEC 61010-2-081: Automatic and semi-automatic laboratory equipment for analysis
IEC 61010-2-201: Control equipment

Measurement Category Selection

Proper selection of measurement category is critical for user safety. The categories reflect decreasing energy levels from the utility service entrance (CAT IV) to protected bench-level circuits (CAT I). Equipment rated for lower categories must never be used in higher category environments, as the transient energy present could exceed protective measures and cause equipment failure or user injury.

IEC 62368: Audio/Video and IT Equipment

IEC 62368-1 represents a hazard-based safety engineering approach that replaces the prescriptive requirements of older standards IEC 60950 (IT equipment) and IEC 60065 (audio/video equipment). This unified standard applies to consumer electronics, computers, networking equipment, and professional audio/video systems.

Hazard-Based Safety Engineering (HBSE)

The fundamental philosophy of IEC 62368 differs from traditional safety standards. Rather than specifying detailed construction requirements, the standard identifies energy sources and requires safeguards to prevent those energy sources from causing pain or injury. Key concepts include:

Energy sources: Electrical, thermal, mechanical, chemical, and radiation energy that could harm users
Safeguards: Protective measures that reduce the likelihood of contact with or effects of energy sources
Classes of persons: Ordinary persons, instructed persons, and skilled persons with different levels of safeguard requirements
Pain and injury thresholds: Transfer of energy below the pain threshold requires no safeguard; above the injury threshold requires multiple safeguards

Key Requirements

Electrically-caused injury: Requirements for touch current, prospective touch voltage, and stored energy in capacitors
Electrically-caused fire: Current limiting, temperature limiting, and enclosure flammability requirements
Hazardous substances: Requirements for batteries, mercury, and other hazardous materials
Mechanical hazards: Protection from moving parts, sharp edges, and instability
Thermal injury: Surface temperature limits and requirements for hot or cold surfaces
Radiation hazards: Requirements for optical radiation including lasers, acoustic energy, and electromagnetic fields

Transition from IEC 60950 and IEC 60065

The transition to IEC 62368 has been completed in most major markets. Products designed to the older standards may no longer be certifiable, and manufacturers must understand the differences in approach. While IEC 62368 offers more design flexibility through its performance-based approach, it also requires more engineering judgment in applying the HBSE methodology.

IEC 60335: Household Appliances

IEC 60335 covers the safety of electrical appliances for household and similar purposes, including those used in shops, offices, and on farms. The standard applies to appliances with rated voltages up to 250 V for single-phase and 480 V for other appliances.

IEC 60335-1: General Requirements

The base standard establishes fundamental safety requirements that apply to all household appliances:

Protection against access to live parts: Requirements for enclosures and barriers prevent user contact with dangerous voltages
Input and current: Appliances must operate safely within their rated parameters
Heating: Temperature limits for various materials and surfaces prevent fire and burn hazards
Leakage current and electric strength: Limits on leakage current and requirements for dielectric withstand ensure shock protection
Overload protection: Thermal cutoffs and other protective devices prevent dangerous overheating
Abnormal operation: Appliances must remain safe during blocked motors, stuck controls, and other fault conditions
Stability and mechanical hazards: Requirements prevent tip-over and injury from moving parts
Components: Requirements for switches, connectors, and internal wiring

Particular Standards (IEC 60335-2-x)

Numerous particular standards address specific appliance types, modifying or supplementing the general requirements:

IEC 60335-2-2: Vacuum cleaners
IEC 60335-2-3: Electric irons
IEC 60335-2-4: Spin extractors
IEC 60335-2-5: Dishwashers
IEC 60335-2-6: Stationary cooking ranges and similar
IEC 60335-2-7: Washing machines
IEC 60335-2-9: Toasters, grills, and similar
IEC 60335-2-11: Tumble dryers
IEC 60335-2-14: Kitchen machines
IEC 60335-2-15: Appliances for heating liquids
IEC 60335-2-21: Water heaters
IEC 60335-2-24: Refrigerators and freezers
IEC 60335-2-25: Microwave ovens
IEC 60335-2-34: Motor-compressors
IEC 60335-2-40: Heat pumps and air conditioners

IEC 61508: Functional Safety

IEC 61508 is the foundational standard for functional safety of electrical, electronic, and programmable electronic safety-related systems. It provides a framework for developing and assessing systems that must function correctly to maintain a safe state or bring equipment to a safe state when hazards arise.

Safety Integrity Levels (SIL)

The standard defines four Safety Integrity Levels (SIL 1 through SIL 4) that represent increasing levels of safety performance. SIL selection is based on risk assessment and determines:

Probability of failure on demand (PFD): For low-demand systems, the probability that the safety function will fail when needed
Probability of dangerous failure per hour (PFH): For high-demand and continuous mode systems, the frequency of dangerous failures
Hardware fault tolerance: The number of faults that can be tolerated while maintaining the safety function
Safe failure fraction (SFF): The proportion of failures that result in safe states
Diagnostic coverage: The proportion of dangerous failures detected by diagnostics

The Standard Series

IEC 61508-1: General requirements establish the overall framework and lifecycle approach
IEC 61508-2: Hardware requirements address random hardware failures and systematic hardware faults
IEC 61508-3: Software requirements cover development processes and verification for safety-related software
IEC 61508-4: Definitions and abbreviations provide consistent terminology
IEC 61508-5: Methods for determining SIL requirements based on risk assessment
IEC 61508-6: Application guidelines provide implementation examples
IEC 61508-7: Techniques and measures overview describes available safety technologies

Sector-Specific Derivatives

IEC 61508 serves as the parent standard for numerous industry-specific functional safety standards:

IEC 61511: Process industries (chemical, petrochemical, pharmaceutical)
IEC 62061: Safety of machinery
ISO 26262: Automotive functional safety
EN 50129: Railway signaling systems
DO-178C: Airborne software (while not IEC-derived, addresses similar concepts)

IEC 60079: Explosive Atmospheres

IEC 60079 provides the framework for equipment intended for use in explosive gas and dust atmospheres. The standard series covers equipment design, installation, inspection, and maintenance to prevent ignition of flammable substances.

Equipment Protection Levels (EPL)

Equipment is classified by the level of protection provided:

Ga, Da: Very high protection level, suitable for Zone 0/20 (continuous or long periods of explosive atmosphere)
Gb, Db: High protection level, suitable for Zone 1/21 (likely to occur during normal operation)
Gc, Dc: Enhanced protection level, suitable for Zone 2/22 (not likely under normal operation)

Protection Concepts

The standard defines multiple protection concepts, each suitable for different equipment types and applications:

IEC 60079-0: General requirements applicable to all protection concepts
IEC 60079-1 (Ex d): Flameproof enclosures contain internal explosions and prevent propagation
IEC 60079-2 (Ex p): Pressurized enclosures maintain positive pressure with protective gas
IEC 60079-5 (Ex q): Powder-filled enclosures prevent ignition through quartz sand filling
IEC 60079-6 (Ex o): Oil immersion submerges potential ignition sources in oil
IEC 60079-7 (Ex e): Increased safety prevents ignition through enhanced construction
IEC 60079-11 (Ex i): Intrinsic safety limits energy below ignition thresholds
IEC 60079-15 (Ex n): Non-sparking equipment for Zone 2 applications
IEC 60079-18 (Ex m): Encapsulation embeds potential ignition sources in compound

Intrinsic Safety (Ex i)

Intrinsic safety is a widely used protection concept that limits electrical and thermal energy below levels capable of causing ignition. Key aspects include:

Entity parameters: Voltage, current, capacitance, and inductance limits for interconnected apparatus
Associated apparatus: Equipment that interfaces intrinsically safe circuits with non-intrinsically safe circuits
Cable parameters: Requirements for interconnecting cables including capacitance and inductance
System documentation: Control drawings showing permitted interconnections

IECEx Certification System

The IECEx System provides international certification for equipment used in explosive atmospheres. Participating countries accept IECEx certificates, eliminating the need for duplicate testing and certification when entering multiple markets.

IEC 61000: Electromagnetic Compatibility (EMC)

The IEC 61000 series establishes requirements and test methods for electromagnetic compatibility, ensuring equipment operates satisfactorily in its electromagnetic environment without introducing intolerable disturbances to other equipment.

Structure of the Standard

IEC 61000 is organized into parts addressing different aspects of EMC:

IEC 61000-1-x: General information, definitions, and methodology
IEC 61000-2-x: Environment descriptions characterizing electromagnetic conditions
IEC 61000-3-x: Emission limits for equipment connected to public networks
IEC 61000-4-x: Testing and measurement techniques
IEC 61000-5-x: Installation and mitigation guidelines
IEC 61000-6-x: Generic standards for specific environments

Key Emission Standards

IEC 61000-3-2: Harmonic current emissions limits for equipment up to 16 A per phase
IEC 61000-3-3: Voltage fluctuations and flicker limits
IEC 61000-3-11: Voltage fluctuations for equipment over 16 A
IEC 61000-3-12: Harmonic current limits for equipment from 16 A to 75 A

Key Immunity Standards

IEC 61000-4-2: Electrostatic discharge (ESD) immunity test
IEC 61000-4-3: Radiated, radio-frequency, electromagnetic field immunity
IEC 61000-4-4: Electrical fast transient (EFT) / burst immunity
IEC 61000-4-5: Surge immunity test
IEC 61000-4-6: Conducted disturbances induced by RF fields
IEC 61000-4-8: Power frequency magnetic field immunity
IEC 61000-4-11: Voltage dips, short interruptions, and variations immunity

Generic Standards

Generic standards provide complete EMC requirements when no product-specific standard exists:

IEC 61000-6-1: Immunity for residential, commercial, and light industrial environments
IEC 61000-6-2: Immunity for industrial environments
IEC 61000-6-3: Emissions for residential, commercial, and light industrial environments
IEC 61000-6-4: Emissions for industrial environments

IEC 60529: IP (Ingress Protection) Ratings

IEC 60529 defines the degrees of protection provided by enclosures against access to hazardous parts, ingress of solid foreign objects, and ingress of water. The IP code provides a standardized way to describe enclosure capabilities.

IP Code Format

The IP code takes the form IP XY, where:

First digit (X): Protection against solid objects and access to hazardous parts (0-6 or X if not specified)
Second digit (Y): Protection against water ingress (0-9 or X if not specified)
Additional letters: Optional suffixes for specific test conditions or protections

First Digit: Solid Object Protection

0: No protection
1: Protection against solid objects over 50 mm (back of hand)
2: Protection against solid objects over 12.5 mm (finger)
3: Protection against solid objects over 2.5 mm (tools, wires)
4: Protection against solid objects over 1 mm (fine wires)
5: Dust protected (limited ingress, no harmful deposits)
6: Dust tight (no ingress of dust)

Second Digit: Water Protection

0: No protection
1: Protection against vertically falling water drops
2: Protection against water drops at 15 degree tilt
3: Protection against spraying water up to 60 degrees from vertical
4: Protection against splashing water from all directions
5: Protection against water jets (6.3 mm nozzle)
6: Protection against powerful water jets (12.5 mm nozzle)
7: Protection against temporary immersion (up to 1 meter for 30 minutes)
8: Protection against continuous immersion (depth and time specified by manufacturer)
9: Protection against high pressure, high temperature water jets

Common IP Ratings

IP20: Indoor equipment with finger protection
IP54: Dust and splash protected, common for outdoor enclosures
IP65: Dust tight and protected against water jets, common for outdoor equipment
IP67: Dust tight and submersible, common for portable outdoor devices
IP68: Dust tight and suitable for continuous submersion, common for underwater equipment

IEC 62304: Medical Device Software

IEC 62304 specifies lifecycle requirements for the development of medical device software and software within medical devices. The standard aligns with quality management system requirements from ISO 13485 and risk management processes from ISO 14971.

Software Safety Classification

Software is classified based on the severity of harm that could result from hazards to which the software contributes:

Class A: No injury or damage to health is possible
Class B: Non-serious injury is possible
Class C: Death or serious injury is possible

Classification determines the rigor of development and documentation requirements, with Class C requiring the most comprehensive processes.

Software Development Lifecycle

The standard requires a planned approach to software development covering:

Software development planning: Documentation of processes, tools, and deliverables
Software requirements analysis: Defining functional and non-functional requirements including safety requirements from risk analysis
Software architectural design: Decomposition into software items and units with defined interfaces
Software detailed design: Specification of software units sufficient for implementation
Software unit implementation: Coding according to defined standards and verification at the unit level
Software integration: Combining software units and items with integration testing
Software system testing: Verification that the integrated software meets requirements
Software release: Documentation and approval for release

Software Maintenance

IEC 62304 requires processes for maintaining software after release, including problem reporting and resolution, change control, and feedback to risk management when issues are identified in the field.

Configuration Management

The standard requires documented configuration management including identification and traceability of software items, change control procedures, and configuration status accounting.

IEC 62471: Photobiological Safety

IEC 62471 evaluates the photobiological safety of lamps and lamp systems, including LEDs. The standard assesses optical radiation hazards including ultraviolet, visible, and infrared radiation, providing risk group classifications to indicate potential hazards.

Photobiological Hazards

The standard evaluates exposure risks from:

Ultraviolet hazard to skin and eyes: Actinic UV radiation causing erythema and photokeratitis
Near-UV hazard to eyes: UVA radiation causing cataract formation
Blue light hazard: Photochemical retinal injury from wavelengths 300-700 nm with peak hazard at 435-440 nm
Retinal thermal hazard: Thermal injury to the retina from visible and IRA radiation
Infrared hazard to eyes: Thermal injury to cornea and lens from near-infrared radiation
Thermal hazard to skin: Burns from visible and infrared radiation

Risk Group Classification

Products are classified into risk groups based on emission levels and exposure duration to reach hazardous limits:

Exempt: No photobiological hazard under reasonably foreseeable conditions
Risk Group 1 (Low Risk): No hazard due to normal behavioral limitations on exposure
Risk Group 2 (Moderate Risk): Does not pose a hazard due to aversion response to bright light or thermal discomfort
Risk Group 3 (High Risk): Hazardous even for momentary exposure

Application to LED Products

With the widespread adoption of LED lighting, IEC 62471 has become increasingly important. Blue light hazard is a particular concern for high-brightness white LEDs, which use blue emitters with phosphor conversion. Product designers must consider viewing geometry, exposure duration, and special populations such as children who may be more susceptible to retinal damage.

Related Standards

IEC TR 62471-2: Manufacturing guidance for non-laser optical radiation safety
IEC 62471-3: LED safety requirements incorporating 62471-1
IEC TR 62778: Application of IEC 62471 for blue light hazard assessment of light sources

Additional Important IEC Standards

IEC 60950: Information Technology Equipment (Legacy)

While superseded by IEC 62368, IEC 60950 established safety requirements for IT equipment including computers, networking hardware, and office equipment. Understanding this standard remains relevant for maintaining legacy products and understanding the evolution to hazard-based approaches.

IEC 61010-2-201: Control Equipment

This particular standard within the IEC 61010 series addresses safety requirements for control equipment used in industrial automation. It covers programmable logic controllers, industrial computers, and other control system components operating in industrial environments.

IEC 62133: Secondary Cells and Batteries

IEC 62133 establishes safety requirements for portable sealed secondary lithium cells and batteries. It addresses hazards including fire, explosion, and chemical leakage that may occur during normal use and reasonably foreseeable misuse. The standard is critical for products containing lithium-ion or lithium-polymer batteries.

IEC 60664: Insulation Coordination

IEC 60664 provides principles for insulation coordination in low-voltage equipment, establishing clearance and creepage distance requirements based on pollution degree, overvoltage category, and insulation type. Understanding this standard is fundamental to electrical safety design.

IEC 61131: Programmable Controllers

IEC 61131 covers programmable logic controllers (PLCs), defining hardware requirements (61131-2), programming languages (61131-3), and application guidelines. The programming languages standard defines ladder diagram, function block diagram, structured text, instruction list, and sequential function chart.

Implementing IEC Standards

Identifying Applicable Standards

Determining which IEC standards apply to a product requires consideration of:

Product function and intended use
Operating environment and conditions
Target markets and regulatory requirements
User population including professional versus consumer use
Power source and voltage levels
Presence of specific hazards (radiation, explosive atmospheres, etc.)

Working with Standards

IEC standards can be obtained from the IEC webstore or through national standards bodies. Many standards are also adopted as national standards (EN, ANSI/UL, JIS, etc.) with identical or near-identical requirements. Understanding the relationship between IEC standards and their national adoptions helps navigate compliance requirements efficiently.

The CB Scheme

The IECEE CB Scheme provides a mechanism for obtaining multinational certification based on a single test report. Key aspects include:

Testing performed by an accredited National Certification Body (NCB)
CB Test Certificate issued covering specified standards
Certificate and test report recognized by participating NCBs in over 50 countries
National deviations documented and addressed
Reduced testing and faster market access

Documentation Requirements

Compliance with IEC standards requires maintaining comprehensive technical documentation including:

Design specifications and drawings
Bill of materials with component certifications
Risk analysis and hazard mitigation documentation
Test reports from accredited laboratories
Production test procedures
User instructions and safety information

Summary

IEC standards form the backbone of international electrotechnical safety and performance requirements. From medical devices governed by IEC 60601 to household appliances under IEC 60335, from functional safety per IEC 61508 to electromagnetic compatibility under IEC 61000, these standards provide the technical requirements that enable global trade while ensuring product safety.

For electronics professionals, developing expertise with relevant IEC standards is essential. Understanding not just the specific requirements but the underlying philosophy and structure of these standards enables more effective product design, efficient certification processes, and successful market access. As technology evolves and new products emerge, the IEC continues to develop new standards and update existing ones, making ongoing engagement with the standards development process valuable for industry professionals.