IEC 61535:2019

Overview

IEC 61535:2019 is an internationally recognized standard issued by the International Electrotechnical Commission (IEC). It specifies requirements for installation couplers intended for permanent connections in fixed electrical installations. The standard applies to two-wire up to five-wire installation couplers (including earth, if provided), with a rated voltage up to and including 500 V AC or DC, and a rated connecting capacity up to and including 10 mm². These installation couplers are designed to provide secure, reliable, and safe connections for both alternating current (AC) and direct current (DC) applications in indoor and outdoor settings.

This second edition of IEC 61535 brings several technical revisions, most notably the extension of the standard to cover DC applications, additional marking requirements for DC use, improvements for outdoor installations, and updates for temperature performance. The standard also refines the updated list of normative references.

Key Topics

IEC 61535:2019 contains essential provisions addressing:

• Scope and Definitions: Defines installation couplers and their application limits.
• Classification and Ratings: Details the number of wires, rated voltage (up to 500 V AC/DC), and connecting capacity (up to 10 mm²).
• Construction and Safety Requirements: Covers general construction, earth connections, mechanical strength, protection against electric shock, safe access to live parts, and protection against ingress of water and solid foreign objects (IP ratings).
• Testing and Compliance: Specifies type tests and routine tests for product conformity, including performance under mechanical stress, temperature variation, and electrical load.
• Marking and Documentation: Sets guidelines for the clear marking of couplers, especially for DC applications, and documentation requirements to support correct and safe installation.
• Outdoor and Environmental Considerations: Expands requirements for use in external environments and prescribes conditions for temperature extremes (typically -5 °C up to +40 °C, with an average not exceeding +35 °C).
• Compatibility and Engagement: Addresses compatibility of coupler systems and prevention of improper or unintended connections.

Applications

Installation couplers in compliance with IEC 61535:2019 are used in a wide range of permanent electrical installations across residential, commercial, and industrial environments. Common use cases include:

• Prefabricated buildings: Rapid electrical system assembly and re-configuration.
• Cable management systems: Integration into cable ducting, tray, ladder, or trunking systems for distributing power.
• Partition walls and suspended ceilings: Facilitating connection and maintenance of wiring routes.
• Commercial infrastructure: Safe, permanent installation in showrooms and furniture, especially where compliance with IEC 60364-7-713 is required.
• Outdoor applications: Enhanced suitability thanks to expanded protection against water and environmental stresses.
• Maintenance & Reconfiguration: Allow connections to be safely opened for maintenance or system alteration, but not intended for frequent or load-bearing engagement or disconnection.

These installation couplers are intended for infrequent use after initial setup and any subsequent maintenance, ensuring long-term safety and security in the electrical infrastructure.

Related Standards

For holistic compliance and best practices in electrical installations, the following standards are directly relevant to IEC 61535:2019:

• IEC 60529: Degrees of protection provided by enclosures (IP Code), important for understanding requirements for ingress protection.
• IEC 60364 (all parts): Electrical installations of buildings, providing broader context and requirements for wiring systems.
• IEC 60664-1: Insulation coordination for equipment within low-voltage systems.
• IEC 60695-2-11: Fire hazard testing using glow-wire flammability methods.
• IEC 60998-2-3 & IEC 60999-1: Particular requirements and safety for connecting devices and clamping units.
• IEC 60112: Determination of proof and comparative tracking indices for insulating materials.

Practical Value

Adhering to IEC 61535:2019 supports enhanced safety, system reliability, and regulatory compliance in universal fixed electrical installations. It establishes clear product requirements for manufacturers and provides installers and specifiers with confidence regarding the permanent safety and performance of installation couplers in both AC and DC fixed wiring systems, for both indoor and outdoor environments.