IEC 60352-7-2020 Solderless connections – Part 7: Spring clamp connections – General requirements, test methods and practical guidance.
4 Requirements
4.1 Workmanship
The connection shall be processed in a careful and workmanlike manner, in accordance with good current practice. Annex A (informative) provides practical guidance and may constitute a benchmark for the assessment of workmanship.
NOTE Some industry sectors (e.g. automotive, aerospace, marine, nuclear, military) use workmanship standards which can be considered upon agreement between manufacturer and user.
4.2 Tools
Tools, if necessary, shall be used and inspected according to the instructions given by the manufacturer.
5 Pre-requisites for basic test schedule
5.1 Spring clamp terminations
5.1.1 Materials
– Materials for the current-carrying parts: suitable grades of copper or copper alloy shall be used.
– Materials for the spring clamp parts: suitable (according to manufacturer’s instructions) grades of copper alloy or steel shall be used.
5.1.2 Surface finishes
The contact area of the current-carrying parts shall be plated with tin or tin-alloy.
The surface shall be free of detrimental contamination or corrosion.
5.1.3 Design features
Spring clamp terminations shall be designed so that the spring clamp parts establish a force to connect the conductors which ensures that the necessary contact pressure is maintained.
In a spring clamp connecting device, each conductor shall be clamped individually.
The openings for use of a tool intended to assist the insertion or withdrawal of the conductor shall be clearly distinguishable from the conductor’s entry hole.
5.1.4 Dimensions
The suitability of a spring clamp connection depends on the dimensions of the termination together with the characteristics of the materials used.
The dimensions of the termination shall be chosen so as to be suitable for (i.e. able to accept) the cross-sectional area of the conductor or the range of conductors for which the termination is designed.
The suitability is verified by applying the test schedules given in Clause 8.
5.2 Wires
5.2.1 General
Wires with solid, stranded and flexible conductors according to IEC 60228 or IEC 601 89-3
shall be used depending on the type of spring clamp terminations.
5.2.2 Materials
The conductor used shall be made of annealed copper.
5.2.3 Dimensions
Wires with the following dimensions shall be used:
– solid wires of 0,32 mm to 3,7 mm nominal diameter (0,08 mm 2 to 1 0 mm 2 cross-section), or
– stranded wires of 0,08 mm 2 to 1 0 mm 2 cross-section, or
– flexible wires of 0,08 mm 2 to 1 0 mm 2 cross-section.
5.2.4 Surface finishes
The conductor shall be unplated or plated with tin or tin-alloy.
The conductor surface shall be free of contamination and corrosion which degrades performance.IEC 60352-7 pdf download.