UL 444 CRD-2015 UL Standard for Safety Communications Cables Section Paragraph Reference 7 24 (New) 8 4 6 (New) Subject New - LP ratings (Edition 4 July 11 2008).pdf

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): DUZXStandard Number: UL 444Standard Title: Standard for Communications CablesEdition Date: July 11, 2008Edition Number: 4Section / Paragraph Reference: 7.24

3、New), 8.4.6 (New)Subject: New LP ratingsSupersedes prior Certification Requirement Decision issued 09-14-2015DECISION:1.4 In Canada, Type CMUC, cross-connect communications cables, “-LP” and the -CI circuit integritymarkings are not recognized by the Canadian Electrical Code, Part I.In the US, Type

4、 CMH is not recognized in the NEC.8.4.6 (NEW) (United States only)Cables that comply with the cable heating test described in Clause 7.24 are permitted to be markedwith the suffix LP (XX) where XX shall be 0.5A, 0.6A, 0.7A, 0.8A, 0.9A or 1.0A to designate thecurrent rating of each conductor in the c

5、able. If so marked, the suffix “LP” shall be addedimmediately after the cable designation. This marking is not required.7.24 (NEW) Cable Heating Test7.24.1 When tested as described in this section, the temperatures measured on the insulation and jacketof the cables, after being corrected to an ambie

6、nt of 45C, shall not exceed the temperature rating of thecable.7.24.2 The cables shall be arranged in a bundle consisting of 192 cables and electrically connected inseries to a power supply capable of providing the rated current marked as part of the LP rating. The inner37 cables shall be arranged i

7、n a hexagonal densest packing structure which represents the worst casethermal dissipation situation. The remaining cables shall be evenly distributed in a random fashion to forma 192 cable bundle. The bundle shall be placed in a 6 foot long (1.83 m) commercially availablenon-metallic conduit (Sched

8、ule 40) with the minimum diameter needed to install the bundle without puttingpressure on the cables. Each end of the conduit shall be filled with insulation.7.24.3 The temperatures shall be measured on the outer jacket and conductor insulation of the centercable at the midpoint of the cable. In add

9、ition, temperatures shall be measured on the jacket andconductor insulation on the center cable two feet (0.6 m) on each side of center thermocouple.7.24.4 Temperatures are to be measured by means of thermocouples consisting of iron and constantanwires not larger than 24 AWG (0.21 mm2) and not small

10、er than 30 AWG (0.05 mm2). When thermocouplesare used in determining temperatures in electrical equipment, it is common practice to employthermocouples consisting of 30 AWG iron and constantan wires with a potentiometer-type of indicatinginstrument. This equipment is to be used whenever a referee me

11、asurement of temperature is necessary.UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION ORDISTRIBUTION WITHOUT PERMISSION FROM UL7.24.5 The thermocouples and related instruments are to be accurate and calibrated in accordance withstandard laboratory practice. The thermocouple wire is t

12、o conform to the requirements specified in theTolerances on Initial Values of EMF versus Temperature tables in the Standard Specification andTemperature-Electromotive Force (emf) Tables for Standardized Thermocouples, ANSI/ASTME230/E230M.7.24.6 A thermocouple junction and adjacent thermocouple lead

13、wire are to be securely held in goodthermal contact with the surface of the material whose temperature is being measured. In most cases,acceptable thermal contact results from securely taping or cementing the thermocouple in place.RATIONALE FOR DECISION:With the increase in current being carried by

14、communications cables, and the associated rise intemperature, there is a need to address the installations with remote powering. The LP cable designationindicates that the cables have been evaluated to carry the marked current in any reasonable worse-caseinstallation without exceeding the temperatur

15、e rating of the cables.Copyright 2015 Underwriters Laboratories Inc.UL, in performing its functions in accordance with its objectives, does not guarantee or warrant thecorrectness of Certification Requirement Decisions it may issue or that they will be recognized or adoptedby anyone. Certification R

16、equirement Decisions are the opinion of Underwriters Laboratories Inc. inpractically applying the requirements of the standard. They do not represent formal interpretations of thestandard under American National Standards Institute (ANSI) processes. UL shall not be responsible toanyone for the use o

17、f or reliance upon Certification Requirement Decisions by anyone. UL shall 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 444 -2-