IEC 61535:2023

IEC 61535:2023 - Overview

IEC 61535:2023 is the International Electrotechnical Commission standard for installation couplers intended for permanent connection in fixed installations. It applies to two‑wire up to five‑wire installation couplers, with or without an earthing contact, rated up to and including 500 V AC or 500 V DC, a rated connecting capacity up to 10 mm², and a rated current ≤ 32 A. This third edition (2023) replaces the 2019 edition and constitutes a technical revision.

Key editorial and technical updates include:

• Inclusion of a definition for “live part” aligned with IEC 61140
• Optional cross‑media documentation (e.g., marking with QR‑Code)
• Consistent terminology for earth/earthing/protective earth
• Additions and corrections in compliance clauses (e.g., Clause 13.3)
• Updates to informative figures and annexes, including a new Annex F for cold climate requirements

Key topics and technical requirements

The standard sets out requirements, tests and documentation for safe and reliable installation couplers used in permanent fixed wiring:

• Ratings and classification: rated voltage, current, and connecting capacity limits; classification rules
• Marking and documentation: required markings, symbol use and optional QR‑Code documentation for traceability
• Safety and protection: protection against electric shock, access to live parts, earthing continuity and dangerous compatibility prevention
• Mechanical and electrical construction: terminals, terminations, contact construction, locking and rotation protection, housing requirements
• Performance testing: insulation resistance, electric strength, temperature rise, breaking capacity, mechanical strength, resistance to heat, ageing and tracking
• Ingress protection: requirements for solid object and water protection (harmful ingress)
• Special tests: Annex F - additional tests and marking for ambient temperatures down to −45 °C; Annex A - routine PE continuity tests; Annex E - DC warning symbol

Practical applications

IEC 61535 is directly applicable to:

• Manufacturers of fixed installation couplers, distribution blocks and modular wiring products
• Design engineers specifying permanent connection couplers for buildings, industrial facilities, and modular installations
• Test laboratories and conformity assessment bodies performing type and routine tests
• Electrical contractors and installers who select compliant couplers for fixed wiring systems
• Specifiers and facility managers ensuring safe earthing continuity, compatibility and environmental suitability (including cold climate installations)

Related standards

• IEC 61140 (safety of persons - protection against electric shock): referenced for the definition of live part
• Use alongside other IEC wiring and connector standards and national wiring regulations for full compliance in installations

Keywords: IEC 61535, installation couplers, fixed installations, earthing contact, rated voltage 500 V, rated current 32 A, cold climate, QR‑Code marking, electrical safety.