1、UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION ORDISTRIBUTION WITHOUT PERMISSION FROM ULUNDERWRITERS LABORATORIES CERTIFICATION REQUIREMENT DECISIONThis Certification Requirement Decision is prepared and published by Underwriters Laboratories (UL). Itis normative for the applicable
2、UL Product Certification Program(s); however, it is currently not part ofthe UL Standard(s) referenced below.Product Category (CCN): NIMX, EOXT, NISD, NJOT, NKCR, NKHJ, NKPZ, NLDX,NLRV, NMFT, NMTR, NRAQ, NRGF, NRKH, NRNT, SWIV2Standard Number: UL 508Edition Date: : January 28, 1999Edition Number: 17
3、Section / Paragraph Reference: Exception to par. 39.3DECISION:Paragraph 39.3 and its exception is as follows:39.3 The clearance and creepage distance at field wiring terminals shall be in accordance with therequirements in Spacings, Section 36.Exception: If the design of the field wiring terminals i
4、s such that it will preclude the possibility of reducedspacing due to stray strands or improper wiring installation, clearances and creepage distances at the fieldwiring terminal may be evaluated in accordance with the Standard for Insulation Coordination includingClearances and Creepage Distances f
5、or Electrical Equipment, UL 840.The following information should be used when determining if the terminals “will preclude the possibility ofreduced spacing due to stray strands or improper wiring installation”:1) Terminals which are rated for solid wire only comply with this requirement2) Terminals
6、which are marked to indicate use with a type of “prepared conductor” comply withthis requirement.Note: Prepared conductor are conductors, the strands of which are soldered or tinned; or the end of which is fitted witha cable lug, eyelet, quick-connect, ring terminal, spade terminal, or similar compo
7、nent, prior to insertion into theterminal.3) Terminals with design features such as recessed terminal pockets comply with thisrequirement.RATIONALE FOR DECISION:This current exception lacks clarity as it relates to the statement “mldr preclude the possibility of reducedspacing due to stray strands o
8、r improper wiring installationsmldr ”. This CRD clarification providesguidance when evaluating devices for compliance with the current exception.Copyright 2007 Underwriters Laboratories Inc.UL, in performing its functions in accordance with its objectives, does not guarantee or warrant thecorrectnes
9、s 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 interpretations of th
10、estandard under American National Standards Institute (ANSI) processes. UL shall not be responsible toUL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION ORDISTRIBUTION WITHOUT PERMISSION FROM ULanyone for the use of or reliance upon Certification Requirement Decisions by anyone. UL shal
11、l not incurany obligation or liability for damages, 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 508 -2-
