IEC 62873-3-3:2022

Overview

IEC 62873-3-3:2022 is the International Electrotechnical Commission (IEC) specification that sets specific requirements for residual current operated circuit-breakers (RCDs) and other devices equipped with screw‑type terminals designed for use with untreated aluminium conductors and with aluminium screw‑type terminals for use with copper or aluminium conductors. This second edition (2022) is a technical revision of the 2016 edition and extends the scope so the document can be referenced by product standards beyond RCDs.

Keywords: IEC 62873-3-3:2022, RCDs, residual current operated circuit-breakers, screw-type terminals, aluminium conductors, aluminium terminals.

Key topics and technical requirements

• Scope and applicability: Applies to devices with screw-type terminals made of copper, copper‑rich alloys (≥58% Cu if worked cold, ≥50% Cu if worked otherwise), or suitably coated metals; also covers terminals manufactured from aluminium material for use with copper or aluminium conductors. Excludes DC applications and flexible aluminium conductors (currently under consideration).
• Construction and marking: Requirements for mechanical design, terminal identification and product information to ensure safe installation and maintenance.
• Connectable conductors and cross-sections: Rules for which aluminium and copper conductor sizes and types may be securely connected to specified terminals (includes treated vs untreated conductor definitions).
• Testing requirements: Includes a range of tests such as current cycling, temperature measurement, mechanical and torque tests, and tests to verify corrosion resistance and long‑term connection stability.
• Test arrangements and acceptance criteria: Defined test loops, equalizers, busbar arrangements and measurement procedures to validate terminal performance under load and thermal stress.
• Interoperability with product standards: Designed to be used together with product standards (e.g., IEC 61008‑1, IEC 61009‑1) and as a normative reference for other device standards.

Practical applications

• Ensures reliable electrical connections when using untreated aluminium conductors in household and similar installations.
• Prevents connection failures caused by thermal cycling, galvanic corrosion or improper torque practices.
• Provides standardized test methods for manufacturers and test laboratories to demonstrate compliance and durable contact performance.
• Enables product standard writers to reference a harmonized set of terminal requirements for devices that must accept aluminium conductors.

Who should use this standard

• Manufacturers of RCDs, RCBOs and related protective devices with screw‑type terminals.
• Design and application engineers specifying terminals for installations where aluminium conductors are used.
• Test laboratories and conformity assessment bodies performing type testing and certification.
• Standards writers and regulatory authorities referencing terminal requirements in product standards.

Related standards

• IEC 62873 series (general framework for residual current operated circuit-breakers)
• IEC 61008‑1 (RCCBs) and IEC 61009‑1 (RCBOs) - for combined application with IEC 62873-3-3:2022

For product development, certification or installation guidance involving aluminium conductors, IEC 62873-3-3:2022 is the authoritative reference for terminal design, testing and safe use.