scope:

This standard provides the preferred ratings for low-voltage ac (635 V and below) power circuit breakers, fused low-voltage ac (600 V and below) power circuit breakers, general purpose dc (325 V and below) power circuit breakers, and low-voltage dc (3200 V and below) power circuit breakers.

Purpose

This standard provides preferred ratings to establish a uniform basis of product design and testing for low-voltage ac and dc power circuit breakers. The ratings in this standard are preferred but are not restrictive. Manufacturers may choose to offer, and users may elect to require, ratings which differ from those in this standard

This revision updates the preferred ratings to reflect changes in the state of the art. Ratings for some obsolete products have been eliminated and new ratings added. This revision is coordinated with the changes in companion standards IEEE Std C37.13™, IEEE Std C37.14™, IEEE Std C37.17™, and IEEE Std C37.27™.^{1, 2}

¹ Information on normative references can be found in Clause 2.

² The IEEE standards or products referred to in this clause are trademarks of the Institute of Electrical and Electronics Engineers, Inc.