December 2025: Essential Electrical Engineering Standards Released

A significant set of international standards for the electrical engineering sector has been published in December 2025, representing pivotal updates for professionals across high-voltage systems, electrical safety, insulation in challenging environments, and industrial energy efficiency. This comprehensive review—Part 4 of 4—captures five major standards released this month, including advanced requirements for switchgear, portable protection devices, high-voltage insulators, and classification of AC motor efficiency. These updates have far-reaching impacts for engineers, compliance teams, and managers tasked with quality assurance and procurement.

Overview

The electrical engineering sector underpins the safe and reliable operation of countless infrastructure, manufacturing, and household systems worldwide. Industry standards establish the benchmarks for product safety, performance, resilience, and operational efficiency necessary to mitigate risk and drive innovation. For professionals navigating complex compliance requirements, understanding the latest international electrical engineering standards is essential.

In December 2025, five new standards were published, advancing global best practices for high-voltage switchgear, portable residual current devices, ceramic and polymer insulators in polluted conditions, and energy efficiency labelling for line-operated AC motors. This article explores what is covered in each standard, highlights critical requirements, and unpacks the overarching impact on technology providers, utilities, integrators, quality and compliance professionals.

Detailed Standards Coverage

CLC IEC/TS 62271-5:2025 - Common Specifications for DC Switchgear and Controlgear

High-voltage switchgear and controlgear – Part 5: Common specifications for direct current switchgear and controlgear

This technical specification establishes essential requirements for high-voltage direct current (HVDC) switchgear and controlgear, specifically for transmission systems operating at voltages of 100 kV and above. Developed under the CENELEC umbrella, it provides a unified framework that harmonizes terminology, performance, ratings, environmental conditions, electrical endurance, and mechanical robustness for DC switchgear—a rapidly growing segment as HVDC networks proliferate globally.

Key aspects:

• Detailed definitions for assemblies, devices, parts, characteristic quantities, and service conditions, accommodating both indoor and outdoor installations.
• Requirements for ratings: direct voltage, insulation levels, continuous current, short-circuit capability (including waveform considerations), and control circuit supply voltages.
• Coverage of normal and special service conditions (pollution, humidity, vibration, altitude, wind), reflecting real-world environments for HVDC equipment.
• Design and construction requirements (e.g., gas/liquid management, earthing), including references to leading international standards (such as IEC 62271-1 and IEC 60071-11).
• Ensures compatibility with contemporary high-voltage DC system architectures and future smart grid developments.

Target users are manufacturers, utilities, engineering consultants, and asset owners involved in HVDC power transmission, substations, and large industrial electrification projects. Transitioning to these requirements ensures enhanced interoperability, reliability, and safety in rapidly expanding transmission infrastructures.

Key highlights:

• Unified requirements for HVDC transmission switchgear (≥100 kV)
• Environmental and electrical stress considerations for robust design
• Integrated guidance referencing over 40 related IEC and EN standards

Access the full standard:View CLC IEC/TS 62271-5:2025 on iTeh Standards

EN IEC 61540:2025 - Portable Residual Current Devices (PRCDs) Without Overcurrent Protection

Portable residual current devices (PRCDs) without integral overcurrent protection for household and similar use

Safety in residential and similar environments is significantly enhanced by portable residual current devices (PRCDs). This standard specifies requirements for the design, use, and compliance of PRCDs that protect users from electrical shock but do not include integrated overcurrent protection. PRCDs defined here are intended for single- and two-phase systems with rated currents up to 16 A (250 V AC) or 32 A (130 V AC), and primarily target use cases where electrical devices are plugged into existing circuits.

Key aspects:

• Details construction and operating characteristics, marking, testing, and endurance requirements for PRCDs.
• Specifies minimum thresholds for residual operating current (not exceeding 0.03 A), response times, dielectric properties, and performance under conditions such as miswiring, supply-side faults, and supply failures (particularly for PRCD-S devices).
• Requirements for mechanical resilience, EMC, resistance to heat and tracking, and protection against unwanted tripping due to surge currents.
• National plug and socket standards are referenced, ensuring device compatibility by market; if none exist, IEC 60884-1 applies.

This standard is essential for manufacturers, importers, market surveillance authorities, and safety professionals responsible for portable or temporary electrical protection. It particularly affects the regulatory landscape for personal protective devices in domestic, commercial, and light industrial use, supporting compliance with both electrical safety regulations and product liability obligations.

Key highlights:

• Safety requirements for PRCDs up to 16/32 A
• Coverage for devices with supply-side fault detection (PRCD-S)
• Guidance for EMC, temperature, and miswiring scenarios

Access the full standard:View EN IEC 61540:2025 on iTeh Standards

IEC TS 60815-2:2025 - Ceramic and Glass Insulators for AC in Polluted Conditions

Selection and dimensioning of high-voltage insulators intended for use in polluted conditions – Part 2: Ceramic and glass insulators for AC systems

Polluted environments (industrial areas, deserts, coastal regions) can dramatically affect high-voltage insulator performance. This specification provides a robust methodology to determine appropriate ceramic and glass insulators, their profiles, and dimensional requirements for AC systems exposed to contamination. The 2025 edition introduces new terms and refinement of correction factors (such as unified specific creepage distance - USCD), making the selection process and risk assessment more precise.

Key aspects:

• Methodology to determine reference unified specific creepage distance (RUSCD) based on site pollution severity (SPS).
• Step-by-step process for evaluating insulator profiles, applying correction factors (for altitude, diameter, parallel insulators), and confirming designs through standardized testing (artificial pollution, withstand voltage).
• Expanded definitions and simplified assessment of shed profiles, nominal creepage, and trunk dimensions for consistency in global projects.
• Practical recommendations and test confirmation guides for product validation in new or retrofit installations.

Utilities, network operators, and manufacturers benefit from this updated methodology, supporting reliable grid operation in challenging locations, reducing insulation-related outages, and streamlining the design/specification process for new builds and upgrades.

Key highlights:

• Advanced selection process for high-voltage insulators in polluted sites
• New, harmonized terminology and profile guidelines
• Comprehensive correction factors for practical implementation

Access the full standard:View IEC TS 60815-2:2025 on iTeh Standards

IEC TS 60815-3:2025 - Polymer Insulators for AC in Polluted Conditions

Selection and dimensioning of high-voltage insulators intended for use in polluted conditions – Part 3: Polymer insulators for AC systems

Polymer (composite) insulators are increasingly used in AC systems due to their lightweight, superior hydrophobicity, and resilience in polluted or harsh environments. This technical specification sets out the selection and dimensioning approach for polymer insulators on high-voltage outdoor installations. The latest edition refines definitions, introduces new correction factors, and acknowledges advances in hydrophobicity transfer materials (HTM).

Key aspects:

• Guidelines to determine RUSCD, appropriate profiles, and minimum creepage requirements tailored to the unique characteristics of polymers.
• Correction factors for altitude, diameter, shed profile, number of parallel insulators, and hydrophobicity transfer (HTM)—which may allow reduced creepage in qualified materials.
• Testing and performance evaluation with particular emphasis on pollution-related degradation (complemented by CIGRE technical brochures referenced in the standard).
• Excludes snow/ice effects due to the current variance in practice and limited knowledge base, focusing on practical pollution-driven scenarios.

Transmission and distribution operators, equipment engineers, and manufacturers dealing with composite insulators for overhead lines or substations will find concrete criteria and improved clarity in aligning product selection with site-specific environmental risks.

Key highlights:

• State-of-the-art selection for polymer AC insulators
• Detailed material guidance and correction for hydrophobicity
• Updated correction/factor methodology and profile recommendations

Access the full standard:View IEC TS 60815-3:2025 on iTeh Standards

IEC 60034-30-1:2025 - Efficiency Classes of Line Operated AC Motors (IE Code)

Rotating electrical machines – Part 30-1: Efficiency classes of line operated AC motors (IE code)

Energy efficiency is now a central focus for industrial and commercial motor applications. IEC 60034-30-1:2025 elevates the global harmonization of energy efficiency classes (IE1–IE5) for line-operated (direct-on-line) AC motors, ranging from 0.12 kW to 1000 kW and up to 1000 V. This latest edition expands the efficiency criteria, clarifies marking/classification protocols, and extends the framework to multiple motor technologies, not limited to induction designs.

Key aspects:

• Five standardized IE classes (IE1 to IE5), with new tables for the highest efficiency levels (IE5).
• Applies to single-speed, 2-, 4-, 6-, 8-pole motors rated for sinusoidal supply (50/60 Hz) and capable of S1 (continuous) duty.
• Clear rules for inclusion/exclusion (e.g., exclusion of DC motors, certain integrated or multi-speed types, and compact drives not separable from frequency converters).
• Marking, rating, and efficiency determination methods harmonized for global comparison, supporting regulatory conformity and procurement decisions across geographies.

Applicable to manufacturers, specifiers, procurement professionals, energy managers, and any organization looking to reduce operational costs and environmental impact through high-efficiency motor selection and compliance with regional energy regulations.

Key highlights:

• Market-wide harmonization of AC motor efficiency labelling
• Introduction of the ultra-high efficiency IE5 class
• Practical tables for rating, selection, and compliance audits

Access the full standard:View IEC 60034-30-1:2025 on iTeh Standards

Industry Impact & Compliance

Business Impact

The latest updates hold important implications for supply chain reliability, product innovation, and operational safety. HVDC expansions, growing electrification, and environmental stressors demand robust, harmonized standards for major electrical infrastructure. Meanwhile, portable safety devices and universal efficiency codes directly influence market competition, procurement choices, and customer safety.

Timelines and Compliance:

• Organizations supplying or specifying electrical products must ensure timely adoption of the 2025 versions in design, tendering, and compliance documentation.
• Regulatory alignment may require amending internal standards, training staff, and updating technical documentation.

Benefits of Adoption:

• Increased product safety and reliability
• Improved compatibility and interoperability in multi-vendor environments
• Demonstrated compliance with international best practices when bidding for global projects
• Long-term reduction of operational and maintenance risks/costs

Risks of Non-Compliance:

• Exposure to regulatory penalties and product recalls
• Reputational harm from safety/quality incidents
• Lost market opportunities where customers demand or mandate up-to-date standards

Technical Insights

Common Technical Requirements

While each new standard addresses distinct product groups, several themes emerge:

• Comprehensive rating and classification methodologies: Ensuring that products are accurately specified, tested, and applied to their intended service environments—be it pollution, temperature extremes, electrical loads, or EMC conditions.
• Rigorous testing and validation: Type testing, routine validation, and resilience against stressors (mechanical, electrical, pollution, environmental) feature prominently, minimizing failure risks in the field.
• Clarity in marking and documentation: Clear guidance on marking, labels, and instructions helps buyers and installers avoid misapplication and supports regulatory audits.
• Performance under abnormal/service conditions: Emphasis on resilience against abnormal events, such as electrical faults, extreme pollution, or mechanical disturbance, supports asset longevity and safety.

Best Practices for Implementation

• Proactively update internal product specifications, purchase requirements, and design manuals.
• Engage cross-disciplinary teams (quality, engineering, procurement, compliance) to ensure all affected processes consider the new requirements.
• Liaise with suppliers and certification bodies early to confirm product conformity to new editions.
• Schedule training and awareness workshops for engineering, installation, and maintenance personnel.
• Integrate standardized labels and documentation updates throughout supply chains.

Testing and Certification Considerations

• Make use of accredited testing laboratories for performance and endurance validation, especially for devices bound for regulated markets.
• Where transitional arrangements are in place, clarify which edition applies for projects tendered/installed during the overlap period.
• Ensure that storage and application conditions match the environmental assumptions in the standard.

Conclusion & Next Steps

December 2025’s release of these five electrical engineering standards ushers in a stronger framework for safety, efficiency, and reliability in high-voltage infrastructure, industrial applications, and consumer protection. Key areas—from HVDC switchgear and advanced residual current protection to the nuanced dimensioning of high-voltage insulators and standardized motor efficiency—are now covered by robust, harmonized international requirements.

Recommended Actions for Organizations:

1. Review and update internal standards to reflect the 2025 editions in procurement, design, and operations.
2. Train relevant personnel on major changes and their practical implications.
3. Audit current and pipeline projects for compliance gaps.
4. Engage with accredited bodies for certification or testing needs.
5. Stay informed: Subscribe or check iTeh Standards regularly for the latest global compliance updates.

Explore the latest standards and technical documentation on iTeh Standards to ensure your organization leads with compliant, efficient, and reliable solutions in electrical engineering.