IEC TS 62993:2017

Guidance for determination of clearances, creepage distances and requirements for solid insulation for equipment with a rated voltage above 1 000 V AC and 1 500 V DC, and up to 2 000 V AC and 3 000 V DC

IEC TS 62993:2017 gives guidance to technical committees which deal with equipment having a rated voltage of more than 1 000 V AC and up to 2 000 V AC, or a rated voltage of more than 1 500 V DC and up to 3 000 V DC. Rated voltages up to 1 000 V AC and 1 500 V DC, as well as higher or lower internal voltages, are covered by IEC 60664-1.
This document applies to equipment for use up to 2 000 m above sea level, and provides guidance for use at higher altitudes.
This document gives guidance for clearances, creepage distances and solid insulation for equipment to achieve safety. It includes methods of electric testing.
The contents of the corrigendum of June 2018 have been included in this copy.

General Information

• Status: Published
• Publication Date: 11-Jul-2017
• ICS: 01 - GENERALITIES. TERMINOLOGY. STANDARDIZATION. DOCUMENTATION
• ICS: 29.080.30 - Insulation systems
• Technical Committee: TC 109 - Insulation co-ordination for low-voltage equipment
• Drafting Committee: JWG 4 - TC 109/JWG 4
• Current Stage: PPUB - Publication issued
• Start Date: 26-Jul-2017
• Completion Date: 12-Jul-2017

Relations

• Corrected By: IEC TS 62993:2017/COR1:2018 - Corrigendum 1 - Guidance for determination of clearances, creepage distances and requirements for solid insulation for equipment with a rated voltage above 1 000 V AC and 1 500 V DC, and up to 2 000 V AC and 3 000 V DC
• Effective Date: 05-Sep-2023

Standards Content (Sample)

IEC TS 62993 ®
Edition 1.0 2017-07
TECHNICAL
SPECIFICATION
Guidance for determination of clearances, creepage distances and requirements
for solid insulation for equipment with a rated voltage above 1 000 V AC and
1 500 V DC, and up to 2 000 V AC and 3 000 V DC

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IEC TS 62993 ®
Edition 1.0 2017-07
TECHNICAL
SPECIFICATION
Guidance for determination of clearances, creepage distances and requirements

for solid insulation for equipment with a rated voltage above 1 000 V AC and

1 500 V DC, and up to 2 000 V AC and 3 000 V DC

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 29.080.30 ISBN 978-2-8322-4501-9

– 2 – IEC TS 62993:2017 © IEC 2017
CONTENTS
FOREWORD . 4
INTRODUCTION . 6
1 Scope . 7
2 Normative references . 7
3 Terms and definitions . 8
4 Basic information for the determination of INSULATION requirements . 11
4.1 General . 11
4.2 Voltages . 12
4.2.1 General . 12
4.2.2 Determination of RECURRING PEAK VOLTAGE . 12
4.3 OVERVOLTAGE categories. 12
4.4 Material groups . 13
4.5 POLLUTION DEGREES . 14
4.5.1 General . 14
4.5.2 Degrees of POLLUTION in the MICRO-ENVIRONMENT . 14
4.5.3 Conditions of conductive POLLUTION . 14
4.5.4 Clearances . 14
5 Dimensioning rules . 15
5.1 Clearances . 15
5.2 CREEPAGE DISTANCES . 17
5.2.1 General . 17
5.2.2 Voltage . 17
5.2.3 POLLUTION. 17
5.2.4 Shape of insulating surface . 17
5.2.5 Relationship to CLEARANCE . 18
5.2.6 CREEPAGE DISTANCES where more than one material is used or more
than one POLLUTION DEGREE occurs . 18
5.2.7 CREEPAGE DISTANCES split by floating conductive part . 18
5.2.8 Dimensioning of CREEPAGE DISTANCES of BASIC INSULATION,
SUPPLEMENTARY INSULATION and REINFORCED INSULATION . 19
5.2.9 CREEPAGE DISTANCES for DC applications . 20
5.3 SOLID INSULATION . 21
5.3.1 General . 21
5.3.2 Withstand of voltage stresses . 21
6 Tests and measurements . 21
6.1 Tests . 21
6.1.1 General . 21
6.1.2 Test for verification of CLEARANCES . 22
6.1.3 Tests for the verification of SOLID INSULATION . 24
6.2 Measuring CLEARANCES and CREEPAGE DISTANCES . 27
Bibliography . 28

Figure 1 – RECURRING PEAK VOLTAGE . 12
Figure 2 – Determination of the width (W) and height (H) of a rib . 18

Table 1 – RATED IMPULSE VOLTAGES according to OVERVOLTAGE CATEGORIES . 13

Table 2 – Clearances to withstand TRANSIENT OVERVOLTAGES . 15
Table 3 – Dimensioning of clearances to WORKING VOLTAGES, TEMPORARY
OVERVOLTAGES or RECURRING PEAK VOLTAGES . 16
Table 4 – Altitude correction factors . 17
Table 5 – CREEPAGE DISTANCES to avoid failure due to tracking . 20
Table 6 – Test voltages based on CLEARANCES and a test site altitude of 2 000 m
above sea level . 23
Table 7 – Correction factors according to test site altitude for test voltages for
CLEARANCES . 24
Table 8 – Severities for conditioning of SOLID INSULATION . 26

– 4 – IEC TS 62993:2017 © IEC 2017
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
GUIDANCE FOR DETERMINATION OF CLEARANCES, CREEPAGE
DISTANCES AND REQUIREMENTS FOR SOLID INSULATION
FOR EQUIPMENT WITH A RATED VOLTAGE ABOVE 1 000 V AC
AND 1 500 V DC, AND UP TO 2 000 V AC AND 3 000 V DC

FOREWORD
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• the required support cannot be obtained for the publication of an International Standard,
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• the subject is still under technical development or where, for any other reason, there is the
future but no immediate possibility of an agreement on an International Standard.
Technical specifications are subject to review within three years of publication to decide
whether they can be transformed into International Standards.
IEC TS 62993, which is a technical specification, has been prepared by IEC technical
committee 109: Insulation co-ordination for low-voltage equipment.

The text of this technical specification is based on the following documents:
Enquiry draft Report on voting
109/158A/DTS 109/162/RVDTS
Full information on the voting for the approval of this technical specification can be found in
the report on voting indicated in the above table.
This
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