1、UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION ORDISTRIBUTION WITHOUT PERMISSION FROM ULUNDERWRITERS LABORATORIES INC. CERTIFICATION REQUIREMENT DECISIONThis Certification Requirement Decision is prepared and published by Underwriters Laboratories Inc.(UL). It is normative for the a
2、pplicable UL Product Certification Program(s); however, it is currently notpart of the UL Standard(s) referenced below.Product Category (CCN): DIVQStandard Number: UL 489Standard Title: Standard for Molded-Case Circuit Breakers, Molded-Case Switchesand Circuit-Breaker EnclosuresEdition Date: January
3、 22, 2013Edition Number: 12Section / Paragraph Reference: 7.1.2.1.4Subject: Calibration for DC Rated Circuit BreakersDECISION:(existing text)7.1.2.1.4 Calibration tests of a circuit breaker may be made at any voltage, using either ac or dc, takinginto consideration the characteristics of the circuit
4、 breaker and the possible conditions of use. A devicenot specifically marked for either dc or ac shall be subjected to the 100-percent test with ac and may besubjected to the 135- and 200-percent test with dc. A circuit breaker rated only for a specific frequencyother than in the range of 50/60 Hz,
5、or dc, shall be tested at the rated frequency, or dc, or both, asappropriate.(NEW)Exception: If it can be shown by a comparison tests that the ac and dc calibration times are essentiallythe same, then either an ac or dc current source may be used.RATIONALE FOR DECISION:The change allows for a dc cir
6、cuit breaker to be tested with ac only if it is proven that the design is notfrequency dependent. Therefore the revision meets the intent of the requirement.Copyright 2013 Underwriters Laboratories Inc.UL, in performing its functions in accordance with its objectives, does not guarantee or warrant t
7、hecorrectness of Certification Requirement Decisions it may issue or that they will be recognized or adoptedby anyone. Certification Requirement Decisions are the opinion of Underwriters Laboratories Inc. inpractically applying the requirements of the standard. They do not represent formal interpret
8、ations of thestandard under American National Standards Institute (ANSI) processes. UL shall not be responsible toanyone for the use of or reliance upon Certification Requirement Decisions by anyone. UL shall not incurany obligation or liability for damages, including consequential damages, arising
9、out of or in connectionwith the use or reliance upon Certification Requirement Decisions. The electronic version of theCertification Requirement Decision is the current version and previously printed copies may be outdated.This document is published as a service to ULs certification customersUL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION ORDISTRIBUTION WITHOUT PERMISSION FROM ULSTANDARD NUMBER: UL 489 -2-No Text on This Page
