NATIONAL FOREWORD

This Indian Standard (Part 2) (First Revision) which is identical with IEC 60947-2 : 2016 ‘Low-voltage switchgear and controlgear — Part 2: Circuit-breakers’ issued by the International Electrotechnical Commission (IEC) was adopted by the Bureau of Indian Standards on recommendation of the Low Voltage Switchgear and Controlgear Sectional Committee and approval of the Electrotechnical Division Council.

This standard was originally published in 2007 and was based on IEC 60947-2 : 2003 ‘Low-voltage switchgear and controlgear — Part 2: Circuit-breakers’, issued by the the International Electrotechnical Commission (IEC). The first revision of this standard has been undertaken to align it with the latest version IEC 60947-2 : 2016.

The major changes in this revision are as follows:

a) Tests for verification of selectivity in Annex A (see A.5.3);

b) Critical load current tests for d.c. circuit-breakers (see 8.3.9);

c) New Annex P for circuit-breakers for use in photovoltaic applications and;

d) New Annex R for residual-current circuit-breakers with automatic reclosing functions.

This Indian Standard is published in five parts. The other parts/sections in this series are:

Part 1 General rules

Part 3 Switches, disconnectors, switch-disconnectors and fuse combination units

Part 4 Contactors and motor-starters

Section 1 Electromechanical contactors and motor-starters

Section 2 a.c. semiconductor motor controllers and starters

Section 3 a.c. semiconductor controllers and contactors for non-motor loads

Part 5 Control circuit devices and switching elements

Section 1 Electromechanical control circuit devices

Section 2 Proximity switches

The text of IEC Standard has been approved as suitable for publication as an Indian Standard without deviations. Certain terminologies and conventions are, however, not identical to those used in Indian Standards. Attention is particularly drawn to the following:

a) Wherever the words ‘International Standard’ appear referring to this standard, they should be read as ‘Indian Standard’.

b) Comma (,) has been used as a decimal marker, while in Indian Standards, the current practice is to use a point (.) as the decimal marker.