BS EN IEC 60305-2021 PDF

Full title and description

STB BS EN IEC 60305:2021 — Insulators for overhead lines with a nominal voltage above 1 000 V. Ceramic or glass insulator units for AC systems — Characteristics of insulator units of the cap and pin type. This document is the 2021 (5th) edition of IEC 60305 adopted as a BS EN IEC standard for use in the UK market and describes mechanical and dimensional characteristics and standard coupling sizes for cap-and-pin string insulator units intended for AC overhead lines and similar substation applications.

Abstract

This standard applies to string insulator units of the cap-and-pin type with ceramic or glass insulating parts, intended for AC overhead lines with nominal voltage greater than 1 000 V (frequency ≤ 100 Hz) and to similar insulators used in substations. It covers units with ball-and-socket or clevis-and-tongue couplings and gives standardized mechanical characteristics, coupling sizes and dimensional requirements for use in clean and polluted areas; electrical withstand levels are addressed in companion test standards. The 2021 edition updates scope wording, adds normative references, specifies electromechanical/mechanical failing loads in Clause 4 and introduces new profile figures.

General information

• Status: Published / In force (BS adoption of IEC 60305:2021).
• Publication date: IEC base publication: 11 January 2021; BS EN adoption published March 3, 2021 (BS EN IEC 60305:2021).
• Publisher: International Electrotechnical Commission (IEC) — adopted/issued as BS EN IEC by the British Standards Institution (BSI).
• ICS / categories: 29.080.10 (Insulators); 29.240.20 (Power transmission and distribution lines).
• Edition / version: 5th edition (Edition 5.0), 2021.
• Number of pages: IEC original: 28 pages; BS EN publication: commonly published as a 20‑page national adoption (presentation/format may vary by publisher).

Key bibliographic and adoption details derived from the IEC publication record and national adoption listings.

Scope

Specifies mechanical and dimensional characteristics and standard coupling sizes for cap-and-pin string insulator units (ceramic or glass) for AC overhead lines above 1 000 V and for similar substation insulators. It applies to ball-and-socket and clevis-and-tongue couplings and covers use in clean and polluted areas; where very heavy pollution or special environmental conditions exist, different creepage distances or profiles may be required while retaining the standardized mechanical coupling characteristics. Electrical withstand values are not the primary subject of this document and are referenced to related test standards.

Key topics and requirements

• Definitions and designation of cap-and-pin (string) insulator unit types and profiles (standard and alternative shed/profile shapes).
• Specified mechanical characteristics including maximum nominal diameter, nominal spacing and minimum nominal creepage distance for each designation.
• Standardized coupling dimensions and types: ball-and-socket and clevis-and-tongue — retaining standard coupling sizes even if some profile dimensions are adapted for special conditions.
• Specification of the electromechanical or mechanical failing load (SFL) requirements (explicit in Clause 4 of the 2021 edition).
• Normative references to related insulator test and dimension standards and updated figures and tables for profiles and dimensions introduced in this edition.

Typical use and users

Used by overhead line designers, utility and transmission/distribution engineers, insulator manufacturers, test laboratories and procurement/specification teams to ensure mechanical compatibility, standardization of coupling dimensions and suitability of cap-and-pin string insulator units for given environmental conditions. Also referenced by standards committees and conformity assessment bodies.

Related standards

Part of the family of IEC standards covering insulators and related tests and dimensions. Commonly referenced related documents include IEC 60383 (parts addressing definitions, test methods and acceptance criteria for ceramic and glass insulators — updated 2023 edition), IEC 60120 (dimensions of ball-and-socket couplings), IEC 60471 (dimensions of clevis and tongue couplings) and other TC 36 publications covering tests and materials. Users should consult IEC 60383-1 and the listed coupling/dimension standards for electrical test methods and acceptance criteria.

Keywords

insulators; cap-and-pin; string insulator units; ceramic insulators; glass insulators; overhead lines; creepage distance; coupling dimensions; ball-and-socket; clevis-and-tongue; electromechanical failing load; IEC 60305; BS EN IEC 60305:2021.

FAQ

Q: What is this standard?

A: It is IEC 60305 (adopted as BS EN IEC 60305:2021) — the fifth edition standard that defines mechanical and dimensional characteristics and standard coupling sizes for ceramic or glass cap-and-pin type string insulator units used on AC overhead lines above 1 000 V.

Q: What does it cover?

A: It covers mechanical/dimensional specifications, designation, coupling types (ball-and-socket or clevis-and-tongue), profile figures, minimum creepage distances and specified mechanical failing loads; electrical withstand/tests are covered by companion test standards such as IEC 60383.

Q: Who typically uses it?

A: Transmission and distribution utilities, overhead-line designers, insulator manufacturers, test laboratories, procurement/specification teams and standards committees use this standard to specify and verify mechanical compatibility and suitability of cap-and-pin insulator units.

Q: Is it current or superseded?

A: Current — IEC 60305:2021 is the active (5th) edition and its BS EN IEC adoption (2021) replaced the earlier 1996 edition (BS EN 60305:1996). Users should apply the 2021 edition for new specifications.

Q: Is it part of a series?

A: Yes — it is part of the IEC insulator standards family (TC 36). Related parts and companion standards include IEC 60383 (tests and acceptance criteria), IEC 60120 and IEC 60471 (coupling dimensions) and other IEC documents addressing tests, materials and specific insulator types.

Q: What are the key keywords?

A: Insulator, cap-and-pin, string insulator unit, ceramic, glass, overhead line, coupling, ball-and-socket, clevis-and-tongue, creepage distance, mechanical failing load, IEC 60305, BS EN IEC 60305:2021.