Overview
IEC 60372:2020 is an international standard issued by the International Electrotechnical Commission (IEC) that specifies the dimensions and test methods for locking devices used with ball and socket couplings of string insulator units. This standard applies when locking devices are supplied separately from the metal fittings standardized under IEC 60120. It defines the shapes, standard dimensions, test procedures, and acceptance criteria crucial for ensuring the reliability and safety of these locking components. The fourth edition of the standard introduces new coupling sizes and updates previously published requirements, reflecting advancements and industry needs since the 1984 third edition.
Key Topics
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Scope and Application
IEC 60372:2020 covers locking devices used with ball and socket couplings in string insulator units, commonly found in electrical transmission infrastructure. When these devices are supplied with insulators or fittings, they are treated as integral parts, with testing conducted as per related standards like IEC 60383-1 and IEC 61325.
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Locking Device Shapes and Dimensions
The standard defines two main types of locking devices:
- Split-pin: Standard and alternative types with specified dimensions ensuring compatibility and secure fastening.
- W-clip: A locking device with detailed dimensional specifications, including a normative gauge described in Annex A to facilitate manufacturing and quality control.
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Test Methods and Acceptance Conditions
The document outlines qualification and sample test procedures to verify:
- Hardness (in accordance with ISO standards for Brinell, Vickers, and Rockwell hardness testing),
- Resistance to bending for split-pins,
- Corrosion resistance to prevent chemical reactions between locking devices and metal fittings.
Acceptance conditions for supply ensure that locking devices meet performance and durability criteria before being installed in the field.
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Manufacturing Guidance
IEC 60372:2020 offers guidance on additional dimensions relevant for manufacturing processes, helping producers maintain consistency and compatibility across different batches and sizes.
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Recent Technical Updates
Key changes in the 2020 edition include introducing two new coupling sizes (36 and 40) and removing content related to the 28B W-clip based on industry feedback.
Applications
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Electrical Transmission Systems
Locking devices conforming to IEC 60372:2020 are essential components in high-voltage overhead power lines, securing the ball and socket couplings of string insulator units used to support and electrically isolate conductors.
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Equipment Manufacturing
Manufacturers of insulators, ball and socket couplings, and related metal fittings rely on this standard to produce compatible and reliable locking devices that meet international quality and safety standards.
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Quality Control and Certification
Suppliers use the prescribed test methods and acceptance criteria to certify locking devices, ensuring conformity during procurement and installation processes.
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Maintenance and Replacement
Utilities engaged in maintenance of transmission lines can use IEC 60372:2020 as a reference for selecting proper locking devices during repair or replacement operations, promoting system reliability.
Related Standards
- IEC 60120 – Standard for metal fittings for ball and socket couplings used in insulator strings; complements IEC 60372 by defining the main coupling components.
- IEC 60383-1 – Insulators for overhead lines – part 1 covers general requirements including testing of insulator units that may incorporate locking devices.
- IEC 61325 – Procedures for testing insulator units including mechanical and electrical performance, ensuring comprehensive assessment when locking devices are supplied as integrated parts.
- ISO 6506-1 / 6507-1 / 6508-1 – Relevant ISO standards referenced for metallic material hardness testing methods, used within IEC 60372 test procedures.
- IEC 60050-471 – International Electrotechnical Vocabulary providing standardized terms related to insulators for clarity and uniformity in documentation.
Keywords: IEC 60372, locking devices, ball and socket couplings, string insulator units, electrical insulators, dimensions, test methods, split-pin, W-clip, high-voltage transmission lines, IEC standards, corrosion resistance, hardness testing, quality control.
Open preview (PDF)Locking devices for ball and socket couplings of string insulator units - Dimensions and tests
