UL 489A PDF

1 Scope

1.1 The requirements of this standard cover single pole or multi-pole DC rated circuit breakers intended for use as branch circuit overcurrent and short-circuit protection in communications equipment.

1.2 All poles of multi-pole circuit breakers covered by this standard operate at the same potential.

1.3 The requirements of this standard cover devices rated 600 volts DC or less.

1.4 This standard is intended to be used with the Standard for Molded-Case Circuit Breakers, Molded-Case Switches and Circuit-Breaker Enclosures, UL 489, as the requirements of this standard modify tests described in that standard.

1.5 Unless otherwise specified, when the term "circuit breaker" is used in this standard, it refers to a circuit breaker intended for use with communications equipment.

Summary of Topics

This revision of ANSI/UL 489A dated June 26, 2023 is being issued to update the title page to reflect the most recent designation as a Reaffirmed American National Standard (ANS). No technical changes have been made.