Essential Electrical Safety and Performance Standards for Road Vehicles: Relays and Overcurrent Protection
- Valentina Bosenko
- 4 days ago
- 6 min read
In today’s automotive and road vehicle industry, maintaining electrical safety and operational reliability is more crucial than ever. The rapid advance of electronics, electrification, and digital controls in vehicles—be they passenger cars, commercial fleets, or next-generation electric vehicles—means businesses must ensure their components and installations meet the highest standards. This article explores two essential, newly updated international standards—EN IEC 63522-29:2025 covering relay capacitance testing, and SIST HD 60364-4-43:2023/oprAA:2025 dedicated to low-voltage installation protection against overcurrent. Understanding and implementing these standards is now indispensable not only to comply with regulations, but also to enhance productivity, security, and scale operations in an evolving market.
Overview / Introduction
The road vehicles sector has seen explosive growth in electrical and electronic components, from basic relays to comprehensive low-voltage installation systems responsible for vehicle safety, engine management, and user comfort. With increasing consumer demands and regulatory requirements, electrical failures or hazards can result in costly recalls, reputational damage, and even a compromise of occupant safety.
International standards play a pivotal role in setting requirements for testing, safety, and performance. Adhering to these standards ensures components such as relays and electrical installations operate reliably during transportation, storage, and all phases of operation. This article breaks down two pivotal standards, explaining their scopes, requirements, and practical implications for businesses seeking reliability and success in the modern automotive marketplace.
What you’ll learn:
The specific requirements and testing procedures defined by EN IEC 63522-29:2025 for relay capacitance
The structure and critical updates within SIST HD 60364-4-43:2023/oprAA:2025 for overcurrent protection in low-voltage installations
How these standards affect business compliance, productivity, and security
Best practices and guidance for implementation
Detailed Standards Coverage
EN IEC 63522-29:2025 - Reliable Relay Performance with Controlled Capacitance
Electrical relays – Tests and measurements – Part 29: Capacitance
This standard sets out the essential procedures and severity levels for testing electrical relays regarding their internal capacitance. As relays are ubiquitous in most electrical vehicle systems—responsible for switching, signal routing, and safety-critical functions—ensuring the capacitance between parts stays within defined safe limits is critical for preventing noise, crosstalk, and unintended behaviors.
What this Standard Covers and Its Scope
EN IEC 63522-29:2025 defines:
The detailed procedures for measuring capacitance in electromechanical relays
Test methods and conditions that mimic transportation, storage, and all forms of operational use
Guidelines for evaluating whether a relay’s capacitance parameters are within product specifications
By applying these conditions, manufacturers and technical staff can verify that relays will operate dependably no matter the environmental or usage context, reducing the risk of electrical interference or malfunction.
Key Requirements and Specifications
All devices under test (DUTs) must be subjected to defined test procedures simulating real-world conditions
Measurements must ensure that the capacitance of the relay’s parts does not exceed specified limits
Detailed reporting formats and evaluation protocols for documenting compliance and test outcomes
Integration with other general requirements for relay testing from harmonized documents (such as EN IEC 63522-0)
Who Needs to Comply
Manufacturers of electrical and electromechanical relays for automotive use
Tier-1 and Tier-2 automotive component suppliers
Third-party testing laboratories and quality assurance teams
Practical Implications for Implementation
Businesses adopting EN IEC 63522-29:2025 can:
Minimize design risks associated with unwanted capacitance
Support overall product quality through robust testing regimens
Facilitate easier market access in regions where this standard is recognized
Reduce warranty claims due to relay failure
Key highlights:
Protects electrical system reliability by ensuring relay capacitance controls
Harmonizes testing approaches, making global supply chain compliance easier
Provides detailed guidance on realistic test conditions and reporting
Access the full standard: View EN IEC 63522-29:2025 on iTeh Standards
SIST HD 60364-4-43:2023/oprAA:2025 - Comprehensive Overcurrent Protection for Low-Voltage Systems
Low-voltage electrical installations – Part 4-43: Protection for safety – Protection against overcurrent
Electrical protection in modern vehicles extends far beyond basic fuses. Today, complex, interconnected low-voltage installations must protect people, equipment, and the vehicle itself against the potentially devastating effects of overcurrents—caused by overloads, short circuits, or equipment failures.
What this Standard Covers and Its Scope
This standard defines comprehensive requirements for:
Protecting live conductors, including PEN (Protective Earth Neutral), PEM (Protective Earth Middle), and PEL (Protective Earth Line) against harmful overcurrent effects
Selecting, positioning, and coordinating protection devices such as circuit breakers, fuses, and disconnects
Structuring the protective measures to ensure both continuity of supply and the highest degree of electrical safety
Key Requirements and Specifications
Mandates “automatic disconnection of supply” as the preferred protection measure, offering rapid isolation in case of hazards
Protection devices must now be installed at the circuit’s origin, unless specific exceptions are detailed in the new normative Annex G
Incorporates advanced requirements for special cases—installations at higher risk of fire or explosion require stricter protection protocols
Revises terminology, adds clarity for neutral/mid-point conductor protection (including management of triplen harmonics)
Who Needs to Comply
Automotive OEMs and system integrators responsible for low-voltage system design
Installers of vehicle charging infrastructure, battery electric systems, and auxiliary equipment
Safety engineers, facility managers, and organizations involved in vehicle maintenance
Practical Implications for Implementation
The adoption of this standard empowers organizations to:
Prevent costly electrical damage, fire, or injury from undetected overcurrents
Comply with the latest harmonized regulations critical for European and international markets
Benefit from clearer, more actionable protection guidelines, supporting both safety and reliability
Key highlights:
Focuses on the strategy and placement of protective devices for optimal safety
Updates and consolidates requirements, making compliance more achievable
Strengthens fire and explosion risk management through targeted measures
Access the full standard: View SIST HD 60364-4-43:2023/oprAA:2025 on iTeh Standards
Industry Impact & Compliance
The implementation of these standards brings substantial benefits across every phase of the product lifecycle in the road vehicle sector.
How these standards affect businesses:
Elevate product quality: Rigorous relay capacitance testing and robust overcurrent protection directly contribute to more reliable and higher-quality vehicles.
Support regulatory compliance: As automotive supply chains become truly global, adhering to internationally harmonized standards minimizes the risk of market entry delays, non-compliance penalties, and costly redesigns.
Facilitate scaling and innovation: Streamlined, proven testing and safety procedures allow companies to efficiently scale production, rapidly prototype new vehicle sub-systems, and seamlessly adopt emerging technologies like electric and autonomous vehicles.
Reduce operational risk: Preventing electrical system failures—often a leading cause of vehicle recalls or warranty claims—helps businesses maintain profitability and a strong market reputation.
Risks of Non-Compliance:
Legal liabilities from failure to meet critical safety requirements
Exposure to regulatory penalties and mandatory recalls
Increased warranty and repair costs
Damage to brand reputation and customer trust
Implementation Guidance
Successfully embedding these standards into organizational practice requires a structured approach.
Common Steps for Implementation:
Training and Awareness: Ensure engineers and technical teams are familiar with the detailed requirements and testing methods specified in each standard.
Gap Analysis: Review current product designs, test protocols, and installation practices against new standard requirements.
Process Integration: Update in-house testing and quality assurance protocols for relay production to incorporate EN IEC 63522-29:2025 procedures. Similarly, adapt installation and protection strategy documentation to align with SIST HD 60364-4-43:2023/oprAA:2025.
Documentation: Implement robust reporting flows as mandated by each standard, supporting transparency both internally and for regulatory inquiries.
Continuous Monitoring: Use real-world incident data to refine protective measures and ensure on-going compliance as standards evolve.
Best Practices for Adopting Standards in Road Vehicle Applications:
Use accredited third-party or independent laboratories for initial compliance validations
Incorporate standard requirements early in the design and engineering cycle to avoid costly late-stage modifications
Leverage digital tools and simulation environments for pre-verification of relay capacitance and overcurrent protection design
Maintain up-to-date records of all test results, compliance certificates, and design changes
Engage with industry groups to stay abreast of pending updates or amendments to these documents
Resources for Organizations:
iTeh Standards Platform for easy access to the latest documents and updates
Manufacturer-specific engineering guides and application notes
Industry forums and technical committees for peer support
Conclusion / Next Steps
Selecting and implementing the right standards is no longer about merely “checking the box” for regulatory compliance; it’s a fundamental strategy for driving quality, safety, and innovation in today’s road vehicle industry. Both EN IEC 63522-29:2025 and SIST HD 60364-4-43:2023/oprAA:2025 represent the latest consensus on best practices for relay performance and comprehensive overcurrent protection—and their adoption is now a must for businesses looking to maintain a competitive edge.
Key Takeaways:
Relay and low-voltage system reliability hinge on rigorous, standardized testing and protection protocols
Compliance ensures market access, operational continuity, and improved customer trust
A structured, proactive approach to implementation delivers full value from these international standards
Your next steps:
Explore the full text of each standard through direct links below
Convene your engineering and quality teams to review current practices
Commit to continuous improvement by staying leaders in standards compliance
Ready to future-proof your products and business? Start your journey to compliance, security, and scalable innovation by exploring the standards below.
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