Overview
EN IEC 60669-2-4:2025 (published by CLC) is the particular standard for isolating switches used in household and similar fixed electrical installations. It is a technical revision of the earlier edition (2004) and supplements Part 1 (general requirements). The standard applies to manually operated general‑purpose isolating switches with a rated voltage up to 440 V and a rated current up to 125 A, for indoor and outdoor use. Key updates include reference alignment to IEC 60669-1:2017, introduction of small ratings (6 A to 13 A), addition of a monophase motor load case (≤10 A, power factor ≥ 0.6) and modifications to key test and dimensional tables.
Key topics and requirements
- Scope & ratings: Covers isolating switches for fixed installations (≤440 V, ≤125 A) and defines standard/preferred values for rated conditional short‑circuit current (I_nc).
- Isolation function & marking: Requires clear front‑visible symbols for ON/OFF and the isolating function; I_nc must be marked on the device or in documentation. Manufacturers must list compatible short‑circuit protective devices (SCPDs).
- Electrical & mechanical tests: Specifies tests for insulation, electric strength, temperature rise, making/breaking capacity, normal operation, mechanical strength, impulse and short‑circuit withstand capability, resistance to heat/fire, tracking and humidity.
- Terminal and conductor requirements: Updates to terminal cross‑section tables and tightening torque requirements for higher current ratings (including 80 A, 100 A, 125 A), ensuring secure connections for rigid and flexible conductors.
- Definitions & test metrics: Introduces terms such as isolating switch, rated conditional short‑circuit current (I_nc) and joule integral (I²t) relevant to selection and verification under fault conditions.
- Environmental categories: Devices intended for overvoltage category III and pollution degree 2 (per IEC 60664‑1).
Applications and who uses this standard
- Manufacturers: design, test and certify isolating switches for domestic and similar installations.
- Product engineers and designers: select appropriate switch ratings, verify terminal sizes, short‑circuit capability and motor/lamp load performance.
- Testing and certification labs: perform compliance testing (insulation, impulse, short‑circuit, temperature rise, mechanical endurance).
- Specifiers, building electricians and installers: choose compliant isolating switches for consumer units, distribution boards and fixed equipment isolation.
- Regulators and procurement teams: reference the standard for safety and conformity in procurement and approvals.
Related standards
- IEC/EN 60669‑1:2017 - General requirements for switches for household and similar fixed electrical installations (Part 1).
- IEC 60664‑1 - Insulation coordination and environmental categories (referenced for overvoltage and pollution degree).
- IEC 61180 - High‑voltage test techniques for low‑voltage equipment (referenced test procedures).
EN IEC 60669-2-4:2025 is essential for ensuring isolating switches meet modern safety, marking and performance expectations for household and similar fixed electrical installations.
