November 2025 Electrical Engineering Standards: Hydropower, Surge Protection, Relays & Explosion Safety

November 2025 marks a significant month for electrical engineering, featuring the release of five new and revised international standards that will shape industry practices for years to come. Covering topics from small hydroelectric installation equipment to surge protection, relay heating tests, and explosion-proof requirements for optical systems, these standards provide fresh guidance for manufacturers, operators, quality managers, and compliance officers. This third installment in our four-part series details key changes and compliance strategies, ensuring your organization remains at the forefront of global best practices.

Overview / Introduction

The electrical engineering sector underpins modern infrastructure, from energy production to transmission, distribution, and equipment safety. International standards are pivotal—they not only guarantee safety and interoperability but also drive innovation while managing risk. November’s slate of new and revised standards brings updated methodologies, harmonization with related specifications, and critical new testing and protection requirements.

In this article, you’ll learn:

• How the latest standards affect small hydroelectric installations, surge protective devices, explosive atmospheres, and relay performance
• Key technical and compliance updates for your sector
• Practical guidance on implementation and certification

Whether you are responsible for safety, procurement, engineering, or operations, these updates provide actionable knowledge to keep your projects compliant and future-ready.

Detailed Standards Coverage

EN IEC 61116:2025 - Guidance for Small Hydroelectric Electromechanical Equipment

Electromechanical equipment guidance for small hydroelectric installations

EN IEC 61116:2025 delivers comprehensive guidance for the installation, procurement, testing, commissioning, and operation of electromechanical equipment in small hydroelectric plants—generally those with impulse or reaction turbines up to about 15 MW and key diameter metrics. This standard is intended for use by developers, plant operators, consulting engineers, and suppliers who need clear definitions for technical specifications, tender evaluation, and quality assurance of hydro equipment.

The document’s structure supports:

• Preparation and evaluation of tenders
• Clear communication and documentation between purchaser and supplier
• Quality control during manufacturing and shop-testing
• Follow-up through site erection, commissioning, and operation

Key requirements and scope:

• General and technical requirements for electromechanical equipment
• Detailed specifications for major hydro plant components: turbines, generators, control systems, transformers, auxiliary equipment
• Procedures for acceptance, operation, and maintenance
• Guidance for inspection, delivery protocols, and documentation

Who needs to comply:

• Hydropower operators and project developers
• Equipment manufacturers and suppliers
• Consulting engineers and EPC contractors involved in small hydro projects
• Plant operators and maintenance personnel

Notable changes from the previous edition:

• Harmonized scope with IEC 62006 to align with emerging sector norms
• Newly introduced technical aspects/TLC for modern equipment and operational practices
• Extensive editorial revision for improved clarity and global harmonization

Key highlights:

• Integrates risk management and site assessment procedures
• Provides templates for technical comparisons in bidding
• Clarifies operational monitoring and documentation requirements

Access the full standard:View EN IEC 61116:2025 on iTeh Standards

EN IEC 61643-11:2025 - Low-Voltage Surge Protective Devices for AC Systems

Low-voltage surge protective devices - Part 11: Surge protective devices connected to AC low-voltage power systems – Requirements and test methods

EN IEC 61643-11:2025 defines the performance, safety requirements, and testing protocols for surge protective devices (SPDs) used in AC power systems up to 1,000 V RMS. SPDs are vital in mitigating risks from lightning and transient overvoltages — essential for infrastructure reliability, workplace safety, and equipment longevity.

Scope and requirements:

• Applies to SPDs connected to AC power circuits at 50/60 Hz (with notes for other frequencies)
• Covers both direct and indirect lightning effects as well as system-originated transients
• Establishes ratings, markings, and test methods for compliance
• Outlines key tests: voltage protection level, short-circuit behavior, overstress response, dielectric integrity, endurance, and more

This edition clarifies application boundaries, test procedures, and technical measures for new modes of protection and evolving grid technologies.

Target industries and users:

• Power utilities and distribution network operators
• Manufacturers of surge protection hardware
• Engineering consultants designing substations and building protection
• Railway sectors where specific product standards don’t exist
• Installers and engineers responsible for electrical safety in commercial/industrial settings

What’s new in 2025:

• Restructuring to assign AC-specific requirements here, common requirements in IEC 61643-01
• Added measurements for combined protection modes and clarified testing for SPD assemblies
• Enhanced T1 and T2 SPD testing for follow current variations, addressing newer technologies/technologies
• Expanded dielectric and clearance requirements, especially for ‘electrically separated circuits’

Key highlights:

• Robust technical protocols for real-world fault and overvoltage events
• Integration with international grid protection practices
• Detailed risk assessment guidance and manufacturer documentation

Access the full standard:View EN IEC 61643-11:2025 on iTeh Standards

IEC 60079-28:2025 - Explosive Atmospheres: Optical Radiation Equipment Protection

Explosive atmospheres – Part 28: Protection of equipment and transmission systems using optical radiation

This third edition establishes internationally recognized practices for protecting equipment—especially those using laser and optical fiber systems—that emit optical radiation when exposed to hazardous (explosive) atmospheres. The risk: optical energy (380 nm to 10 µm) may heat surfaces or particles to ignition, or very rarely, induce breakdown of gases via focused laser beams.

Scope and application:

• Covers Ex Equipment, Ex associated equipment, or Ex Components with optical systems in hazardous locations
• Addresses laser, optical fiber, and convergent beam systems
• Specifies requirements for design, testing, verification, and marking (across all Equipment Protection Levels, or EPLs)
• Provides major annexes on ignition mechanisms, cable design, and pulse assessment

Who should comply:

• Manufacturers and integrators of safety-rated optical and laser systems for use in hazardous (explosive) atmospheres
• Operators and technical managers in oil, gas, petrochemicals, chemical processing, grain handling, and mining
• Certification bodies and inspection agencies

Major changes in Edition 3:

• Removal of ignition testing as a verification method (enhances repeatability)
• Detailed procedures for inherently safe (‘op is’), protected (‘op pr’), and interlocked (‘op sh’) optical systems
• Expansion of marking and documentation requirements for hazardous area installations
• Guidance clarified for calculation-based safety assessments

Key highlights:

• Focuses on real-world ignition risks caused by heating or rare direct laser gas breakdown
• Offers clear boundaries for exclusions (e.g., Class 1 lasers, fully enclosed systems)
• Supplements general Ex standards (IEC 60079-0) with optical-specific controls

Access the full standard:View IEC 60079-28:2025 on iTeh Standards

EN IEC 63522-10:2025 - Electrical Relays Heating Test Methods

Electrical relays – Tests and measurements – Part 10: Heating

EN IEC 63522-10:2025 introduces standardized testing methods to evaluate how electrical relays withstand heating during typical operation, storage, and transit. Reliable relay performance is essential throughout control, power management, and safety systems in electrical engineering.

Scope and details:

• Sets up-relay heating test protocols for both group and single mounting arrangements
• Covers mounting, energizing, and measurement techniques (including temperature monitoring with thermocouples)
• Addresses torque settings for terminal screws, environmental conditions (such as heat chambers without forced convection), and test report documentation
• Defines pass/fail criteria based on permissible temperature rise and evaluation of relay coils and terminals

Target audience:

• Relay designers and manufacturers
• Test labs and quality assurance teams
• Electrical switchgear and controls system engineers

Why it matters:

• Ensures reliability and operational safety for relays in service
• Provides a unified basis for comparing relay performance under heating stress
• Supports industry transparency and harmonized certification

Key highlights:

• Group mounting and single relay setups covered
• Detailed installation and testing instructions ensure reproducibility
• Reporting guidance supports traceability and regulatory compliance

Access the full standard:View EN IEC 63522-10:2025 on iTeh Standards

Industry Impact & Compliance

Adoption of these new and revised standards brings clear benefits to businesses and organizations operating in the electrical engineering industry:

• Improved safety: Enhanced procedures minimize risks of equipment failures, surges, or ignition events—directly protecting people, assets, and critical infrastructure.
• Streamlined procurement and contract management: Clear guidelines for tendering, evaluation, and acceptance drive cost-effective, transparent purchasing processes.
• Global harmonization: Alignment with international best practices enables market access and interoperability of equipment, especially for cross-border projects.
• Future readiness: The focus on modern technologies (such as optical safety in explosive atmospheres and new surge protection test methods) allows you to stay ahead amidst technological evolution.
• Compliance timelines: Implementation deadlines range from late 2026 to late 2028, providing organizations with a structured period for phase-in planning and training.

Risks of non-compliance include:

• Increased liability and operational risks (including possible catastrophic events)
• Lost business opportunities due to ineligible tenders or failed inspections
• Fines or regulatory penalties
• Reputational harm

Proactive adoption ensures legal compliance and competitive positioning.

Technical Insights

Several best practices and technical considerations span these new standards:

• Documentation & Traceability: Maintain records of equipment specifications, acceptance tests, and manufacturer data as specified; ensuring traceability streamlines audits and supports incident investigations.
• Testing and Certification: Use accredited labs and certification bodies for SPD testing under EN IEC 61643-11:2025 and relay thermal evaluations under EN IEC 63522-10:2025. Ensure maintenance of Ex marking and verification protocols for IEC 60079-28:2025.
• Procurement: Specify products that explicitly claim compliance to the latest editions and request supporting documentation from suppliers.
• Staff Training: Ensure that installation and maintenance teams are trained to the latest procedures—including safety precautions when handling optical and electrical hazards.
• Interoperability: Where possible, leverage harmonization between new and existing standards to minimize integration problems.

Implementation steps:

1. Conduct gap assessment against the new standards
2. Update internal procedures, drawings, and procurement specifications
3. Train responsible engineering and O&M staff
4. Schedule staged upgrade or retrofit planning with vendors and partners
5. Engage with conformity assessment and certification partners early

Conclusion / Next Steps

The November 2025 updates to international standards for electrical engineering are substantial, touching on hydropower electromechanical systems, surge protection, relay reliability, and the safe use of optical technology in hazardous atmospheres.

Key takeaways:

• Each standard brings clear, evidence-based methodologies to bolster safety, performance, and legal compliance
• Early engagement with updated standards ensures cost-effective implementation and competitive advantage
• Access authoritative documentation via iTeh Standards for up-to-date full-text references and continuous sector intelligence.

Recommendations:

• Review each standard’s requirements and implementation dates
• Initiate necessary gap assessments, documentation reviews, and team training now
• Stay ahead by subscribing to iTeh Standards for the latest updates and compliance support

Stay compliant and future-proof your operations—explore the full standards suite on iTeh Standards!