NATIONAL FOREWORD

This Indian Standard (Part 2) which is identical with IEC 61009-1 : 2012 ‘Residual current operated circuit-breakers with integral overcurrent protection for household and similar uses (RCBOs) — Part 1: General rules’ issued by the International Electrotechnical Commission (IEC) was adopted by the Bureau of Indian Standards on the recommendation of the Low Voltage Switchgear and Controlgear Sectional Committee and approval of the Electrotechnical Division Council.

The second revision of this standard has been undertaken to align it with IEC 61009-1 : 2012 Ed. 3.1, which consists of IEC 61009-1 : 2010 (Ed.3.0) and its Amendment 1 (2012). A vertical line in the margin shows where the base publication has been modified by Amendment 1. Additions and deletions are displayed in red, with deletions being struck through.

The significant technical differences of IEC 61009-1 : 2012 from IS 12640 (Part 2) : 2008 are as follows:

a) Complete revision of EMC sequences, including the new test T.2.6, already approved in IEC 61543;

b) Clarification of RCDs current/time characteristics reported in Tables 2 and 3;

c) Revision of test procedure for IÄn between 5 A and 200 A;

d) Tests for the use of RCBOs in IT systems;

e) Testing procedure regarding the 6mA d.c. current superimposed to the fault current;

f) Improvement highlighting RCDs with multiple sensitivity; and

g) Some alignments with IEC 60898-1.

The text of IEC Standard has been approved as suitable for publication as an Indian Standard without deviations. Certain 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.