IEC 62271-106:2011 is applicable to a.c. contactors and/or contactor-based controllers and motor-starters designed for indoor installation and operation at frequencies up to and including 60 Hz on systems having voltages above 1 000 V but not exceeding 24 000 V. It is applicable only to three-pole devices for use in three-phase systems, and single-pole devices for use in single-phase systems. Two-pole contactors and starters for use in single-phase systems are subject to agreement between manufacturer and user. This standard cancels and replaces the second edition of IEC 60470 published in 1999. It constitutes a technical revision. This edition includes the following significant technical changes with respect to IEC 60470:1999: - Scope and object: The voltage range covered by the standard was expanded from 12 kV to 24 kV. Overload relay calibration and testing is not covered by this standard. - 3 Terms and definitions: Added definitions for capacitor switching classes. - 4.1 Rated voltage: Added 15, 17,5 and 24 kV as standard voltage values. - 4.109.2 Starting duty of reduced-voltage starters: Added ratings for autotransformer and reactor starters (was in the testing section). - 4.112 Rated capacitive switching currents: Added capacitor switching current ratings. - 5.101 Protective relays: Removed the requirements for overload relays. This section is obsolete since there are only a few MV starters fitted with thermal overload relays and electronic relays have their own standards. - 6.2.5 Application of the test voltage and test conditions (former 6.2.2 b)): Changed wording of requirement for impulse across the open gap of vacuum contactors. - 6.4.2 Auxiliary circuits: The requirement for resistance checks of auxiliary circuits was deleted. - 6.5.5.104 Temperature rise of the auto transformer or reactor for two step auto transformer or reactor starters: Reworded to transfer ratings to subclause 4.109.2. - 6.102.9 Condition following making and breaking tests: Gave specific direction as to what the tolerance should be based on where the resistance was to be checked. - 6.104 Short-circuit current making and breaking tests: Clarified test conditions for short-circuit testing. - 6.109 Capacitive current switching tests: Added capacitive current switching tests. - Annex B: Added Table B.1 - Tolerances on test quantities for type test.