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): IZLT, IZMR, IZNDStandard Number: UL 4248-1Standard Title: Standard for Fuseholders - Part 1: General RequirementsEdition Date: February 28, 2007Edition Numbe
3、r: 1Section / Paragraph Reference: Multiple: definitions, construction, performanceSubject: Allow for multilple cables per phase smaller than 1/0 AWGDECISION:Use the following clauses in conjunction with UL 4248-12.1.15 Special Purpose Fuseholder “Not for General Use” a fuseholder having special fea
4、tures limitingtheir suitability to specific applications.6.1.8 Fuseholders having special features limiting their suitability to specific applications shall be markedSpecial Purpose - Not For General Use, or equivalent. Instructions shall be provided by themanufacturer detailing the application(s).
5、See 7.5.10.7.1.3 Special purpose “Not for general use” Special purpose fuseholders shall comply with theconstruction requirements of this standard, except the type or construction of the terminals are such thefuseholder can only be used in specific equipment applications and is not suitable for fiel
6、d installation inaccordance with NEC.(Revised) Table 7.2, Note For terminals that accommodate multiple conductors, see 7.5.9 and 7.5.10.7.5.9 Fuseholders intended for paralleling field wired conductors shall be sized for accommodatingparalleled conductors 1/0 AWG and larger, with the ampacity of the
7、 fuseholder based on multiplying thenumber of conductors by the conductor ampacity.7.5.10 Fuseholders intended for factory wiring only, the ampacity shall be specified by the manufacturerand determined by compliance with performance testing outlined in this Standard. When factory wiredterminals are
8、intended for multiple conductors per phase, the fuseholders shall be marked in accordancewith 6.1.8.8.5.1.1A A fuseholder marked in accordance with 6.1.8 shall comply with 8.5.1.1 except as revised below.Separate short-circuit withstand tests shall be conducted.a) One test shall be conducted using t
9、he maximum size line side conductor(s) corresponding tothe ampere rating of the fuseholder. The load side conductor(s) shall match the ampacity of theline side conductor(s). The largest load side conductor(s) shall be used along with whateversmaller load side conductors are needed to match the ampac
10、ity rating of the line sideconductor(s).UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION ORDISTRIBUTION WITHOUT PERMISSION FROM ULb) The second test shall be conducted using the maximum size line side conductorcorresponding to the ampere rating of the fuseholder. The load side conduct
11、or shall be theminimum size conductor, and only one is to be used per pole. Multiple load side conductors arenot used to match ampacity.RATIONALE FOR DECISION:Presently the NEC only allows paralleling of cables 1/0 AWG and larger (applicable to field wiring).However, there are factory wiring applica
12、tions, such as internal wiring of industrial control panels, thatallow paralleling of cables under certain conditions. For these applications, the additional requirementsnoted above are appropriate.Copyright 2014 Underwriters Laboratories Inc.UL, in performing its functions in accordance with its ob
13、jectives, does not guarantee or warrant thecorrectness 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 standar
14、d. They do not represent formal interpretations 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,
15、including consequential damages, arising 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 customersSTANDARD NUMBER: UL 4248-1 -2-
