Overview
IEC 60352-7:2002 - "Solderless connections - Part 7: Spring clamp connections - General requirements, test methods and practical guidance" is an IEC international standard that defines how to evaluate and qualify spring-clamp (spring‑clip) solderless connections. It determines suitability under specified mechanical, electrical and atmospheric conditions for connections made with stripped wire without further preparation. The standard contains design requirements, accepted materials and finishes, test methods and practical guidance for reliable spring‑clamp terminations.
Key topics and technical requirements
- Scope and wire types: Applies to solid, stranded and flexible conductors per IEC 60228 and IEC 60189‑3 - solid wires nominal diameter 0.32 mm to 3.7 mm (0.08 mm² to 10 mm²) and stranded/flexible conductors 0.08 mm² to 10 mm².
- Materials and finishes:
- Current‑carrying parts: suitable copper or copper alloys.
- Spring parts: suitable copper alloy or steel.
- Contact areas: plated with tin or tin‑alloy and free of contamination/corrosion.
- Design and workmanship:
- Each conductor must be clamped individually.
- Spring force and termination dimensions must suit the intended wire range; suitability is verified by testing.
- Clear tool openings, correct strip length, undamaged stripped conductors and all strands located inside the termination are required.
- Test methods and verification:
- Two test schedules: Basic (for terminations conforming to Clause 4) and Full (for designs/materials outside Clause 4).
- Tests cover mechanical (tensile, wire deflection, vibration), electrical (current carrying, contact resistance, current cycling) and atmospheric/corrosion performance.
- Practical test arrangements, severity levels and specimen counts are specified; normative references include IEC 60068‑1 (environmental testing) and IEC 60512 (connector tests).
Applications and who uses it
- Manufacturers of terminal blocks, spring‑clamp terminals, push‑in connectors and PCB-mounted spring clamps use IEC 60352‑7 for design and qualification.
- Design and test engineers apply the standard to verify compatibility with conductor types, to set tooling/assembly instructions, and to establish current‑rating and contact resistance criteria.
- Compliance and QA labs use the described test schedules to validate production batches and new materials/finishes.
- Product specifiers in telecommunications and electronic equipment use it to ensure electrical stability and environmental robustness.
Related standards
- IEC 60228 - Conductors of insulated cables
- IEC 60189‑3 - Equipment wires (PVC insulated)
- IEC 60068‑1 - Environmental testing - General
- IEC 60512 - Connectors for electronic equipment - Tests and measurements
- IEC 60884‑1 - Plug and socket outlets (general requirements)
Keywords: IEC 60352‑7:2002, spring clamp connections, solderless connections, test methods, spring‑clamp terminations, wire sizes, contact resistance, environmental testing.
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