IEC TS 60815-1-2025 PDF

Full title and description

IEC TS 60815-1:2025 — Selection and dimensioning of high-voltage insulators intended for use in polluted conditions - Part 1: Definitions, information and general principles. This Technical Specification provides definitions, methods to evaluate site pollution severity (SPS), input parameters and general principles to guide the selection and dimensioning of outdoor high-voltage insulators for polluted environments.

Abstract

This second-edition Technical Specification (2025) updates and replaces the 2008 edition. It standardizes terminology (including new/modified terms such as RUSCD, creepage factor, SPS value/class, hydrophobicity transfer), refines methods to determine site pollution severity, introduces an extremely heavy pollution class (f) for special cases, defines reference insulator parameters and profiles, revises laboratory and field measurement methods (including DDDG and relations between SDD and ESDD), updates correction factors (altitude, diameter, profile, parallel insulator number) and updates the recommended statistical approach for selection and dimensioning of insulators in polluted conditions.

General information

• Status: Published / Valid (Technical Specification).
• Publication date: 24 November 2025.
• Publisher: International Electrotechnical Commission (IEC), TC 36 (Insulators).
• ICS / categories: 29.080.10 (Insulators).
• Edition / version: Edition 2.0 (2025).
• Number of pages: 60 pages.

Bibliographic and edition details are recorded by the IEC webstore and national standards bodies.

Scope

Applies to the selection and determination of relevant dimensions of outdoor high-voltage insulators for polluted environments. Part 1 gives definitions, describes approaches and input parameters (system requirements, environmental/pollution conditions), specifies methods to determine site pollution severity (SPS value and class) and provides general guidance that supports the specific material/geometry guidance given in subsequent parts of the series (ceramic & glass, polymer, DC insulators). It is intended for application to AC and DC systems as noted and references the other parts of IEC 60815 for specific insulator types.

Key topics and requirements

• Definitions and standardized terminology for pollution-related parameters (RUSCD, USCD, creepage factor, SPS value/class, HTM, hydrophobicity transfer).
• Three proposed approaches to selection/dimensioning and guidance on choosing an appropriate approach for a given system and site.
• Methods to evaluate site pollution severity (SPS) including field and laboratory measurement guidance and grading into SPS classes.
• Introduction of an extremely heavy pollution class (f) for special situations where class e is insufficient (RUSCD for f not prespecified).
• Specification of reference insulator parameters and profiles (including type B profiles for cap-and-pin and long-rod geometries).
• Revised measurement methods (DDDG) and updated relations between SDD and ESDD for artificial pollution testing.
• Correction factors and adjustment rules (altitude, shed diameter/profile, parallel insulator arrangements) to convert RUSCD of reference insulator to USCD of candidate insulator.
• Guidance on material behaviour, profile suitability, and the new concept of hydrophobicity transfer material (HTM) allowing reduced creepage in some cases.
• Updated statistical methods and decision-making criteria for selecting appropriate creepage distance and insulator geometry under expected site conditions.

These elements reflect the principal technical changes and additions in the 2025 revision.

Typical use and users

Engineers and specialists in transmission and distribution utilities, substation designers, insulator manufacturers, test laboratories, consultants, procurement teams and standards committees use this TS to select insulator types and creepage dimensions appropriate to specific polluted sites, to prepare specifications, and to interpret field and laboratory pollution measurements when assessing insulator performance under contaminated conditions.

Related standards

This part is the general volume of the IEC 60815 series; the series also includes IEC TS 60815-2 (ceramic and glass insulators for AC systems), IEC TS 60815-3 (polymer insulators for AC systems) and IEC TS 60815-4 (insulators for DC systems). The 2025 edition supersedes IEC TS 60815-1:2008. Users should consult the other parts of IEC 60815 for material- and geometry-specific requirements and applicable laboratory test procedures.

Keywords

High-voltage insulators, polluted conditions, creepage distance, RUSCD, USCD, site pollution severity (SPS), hydrophobicity transfer material (HTM), DDDG, SDD, ESDD, insulator selection, IEC 60815 series, TC 36.

FAQ

Q: What is this standard?

A: IEC TS 60815-1:2025 is the general (Part 1) Technical Specification of the IEC 60815 series that defines terms, evaluation methods and general principles for selecting and dimensioning outdoor high-voltage insulators for polluted environments.

Q: What does it cover?

A: It covers definitions, input parameters (system and environmental), methods to determine site pollution severity (SPS value and class), reference insulator definitions and profiles, correction factors to translate reference measurements to candidate insulators, laboratory and field measurement updates (including DDDG and SDD/ESDD relations), material guidance (including HTM), and statistical decision methods for selecting creepage and insulator geometry.

Q: Who typically uses it?

A: Transmission and distribution utilities, substation and line designers, insulator manufacturers, test laboratories, consultants, procurement/specification writers and standards committees use it to ensure insulator selection matches local pollution conditions and system performance requirements.

Q: Is it current or superseded?

A: The 2025 edition (Edition 2.0) is the current Technical Specification, published 24 November 2025; it supersedes IEC TS 60815-1:2008. Users should apply the 2025 edition for new designs and specifications.

Q: Is it part of a series?

A: Yes — it is Part 1 (general principles) of the IEC 60815 series; the series includes Parts 2, 3 and 4 addressing ceramic/glass AC, polymer AC and DC insulators respectively. Consult the respective parts for material- and system-specific prescriptions.

Q: What are the key keywords?

A: Keywords include: site pollution severity (SPS), creepage distance, RUSCD, USCD, hydrophobicity transfer material (HTM), DDDG, SDD, ESDD, insulator selection, polluted environments, IEC 60815.