Content Description

IEC 60305:2021 applies to string insulator units of the cap and pin type with insulating parts of ceramic material or glass, intended for AC overhead lines with a nominal voltage greater than 1 000 V and a frequency not greater than 100 Hz. It also applies to insulators of similar design used in substations. This document applies to string insulator units of the cap and pin type either with ball and socket couplings or with clevis and tongue couplings. This document applies to string insulator units for use on overhead lines in clean areas and polluted areas. For use in areas characterized by very heavy pollution levels and for other particular or extreme environmental conditions, it may be necessary for certain dimensions to be changed and insulator units having different creepage distances, spacing and forms may be preferred (for example, flat profile, hemispherical etc.). Insulators for use on DC systems may also need different dimensions. In any case, it is applicable that the standardized mechanical characteristics of this document and coupling sizes are retained. This fifth edition cancels and replaces the fourth edition published in 1995. This edition includes the following significant technical changes with respect to the previous edition:
- wording in Scope changed from "it is recommended" to "it is applicable";
- new normative references added;
- electromechanical or mechanical failing load in Clause 4 specified;
- new figures added showing profiles.

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The IEC is a global, not-for-profit membership organization, whose work underpins quality infrastructure and international trade in electrical and electronic goods. The IEC facilitates technical innovation, affordable infrastructure development, efficient and sustainable energy access, smart urbanization and transportation systems, climate change mitigation, and increases the safety of people and the environment.

The IEC brings together ~170 countries and provides a global, neutral and independent standardization and conformity assessment platform for 30 000 experts globally. It administers 4 Conformity assessment systems whose members certify that devices, systems, installations, services and people work as required.

The IEC publishes around 10 000 IEC International Standards which together with conformity assessment provide the technical framework that allows governments to build national quality infrastructure and companies of all sizes to buy and sell consistently safe and reliable products in most countries of the world. IEC International Standards serve as the basis for risk and quality management and are used in testing and certification to verify that manufacturer promises are kept.