UL-493-BULLETINS-2007.pdf
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1、FOR INTERNAL UL OR CSDS USE ONLY NOT FOR OUTSIDE DISTRIBUTION Subject 493 March 23, 2007 SUMMARY OF TOPICS The following changes in requirements are being proposed: This Proposed Ninth Edition of the Standard for Thermoplastic-Insulated Underground- Feeder and Branch-Circuit Cables, UL 493, Includes
2、 the Following Signifi cant Changes: a) Revision of SI Units for Tensile Strength and Addition of Minimum Ultimate Elongation for Specimens of Non-UF-B Cable; b) Clarifi cation that the Option for the Continuous Eddy-Current Procedure is not Limited to Single Conductor Cable; c) Revision of the Edge
3、wise Method to Refl ect Present Practice; d) Clarifi cation of Ungrounded Conductor Color Requirements; e) Clarifi cation of Cable Types Additionally Permitted to be Marked for use on Type NMC-B Cable; f) Miscellaneous Editorial Revisions and Clarifi cations Including Updated Practices, Terminology,
4、 and Standards References, and Various Improved Wordings STP BALLOTS DUE: May 7, 2007 COMMENTS DUE: May 7, 2007 For your convenience in review, proposed additions to existing requirements are shown underlined and proposed deletions are shown lined-out. This Proposed Ninth Edition of the Standard for
5、 Thermoplastic-Insulated Underground-Feeder and Branch-Circuit Cables, UL 493, Includes the Following Signifi cant Changes: a) Revision of SI Units for Tensile Strength and Addition of Minimum Ultimate Elongation for Specimens of Non-UF-B Cable; b) Clarifi cation that the Option for the Continuous E
6、ddy-Current Procedure is not Limited to Single Conductor Cable; c) Revision of the Edgewise Method to Refl ect Present Practice; d) Clarifi cation of Ungrounded Conductor Color Requirements; e) Clarifi cation of Cable Types Additionally Permitted to be Marked for use on Type NMC-B Cable; f) Miscella
7、neous Editorial Revisions and Clarifi cations Including Updated Practices, Terminology, and Standards References, and Various Improved Wordings RATIONALE Proposal submitted by: Thomas Cybula, UL. A number of requirements in UL 493 have been identifi ed as in need of updating. Accordingly the standar
8、d is being presented as the proposed Ninth Edition and includes the following signifi cant changes: a) Revision of SI Units for Tensile Strength and Addition of Minimum Ultimate Elongation for Specimens of Non-UF-B Cable Copyright Underwriters Laboratories Inc. Provided by IHS under license with ULL
9、icensee=IHS Employees/1111111001, User=Wing, Bernie Not for Resale, 04/02/2007 01:02:21 MDTNo reproduction or networking permitted without license from IHS -,-,- FOR INTERNAL UL OR CSDS USE ONLY NOT FOR OUTSIDE DISTRIBUTION The use of Mega-Pascals (MPa) as the SI unit of tensile strength is the pref
10、erred method in ULs Wire and Cable Standards. UL is therefore adding MPa and removing MN/m2, N/cm2, and kg/mm2from Table 8.1. Table 8.1 is also revised to add the minimum ultimate elongation for cable from specimens not marked -B. b) Clarifi cation that the Option for the Continuous Eddy-Current Pro
11、cedure is not Limited to Single Conductor Cable The reference to single-conductor cable presently contained in paragraph 12.3 has been deleted to remove the implication that the option to substitute a continuous eddy-current procedure is limited to single-conductor cable. c) Revision of the Edgewise
12、 Method to Refl ect Present Practice The description of the edgewise method in paragraph 21.3 has been enhanced to refl ect present practice such as specifying where the cable is to be gripped and that it should be twisted 90 in opposite directions as opposed to being twisted through 180. d) Clarifi
13、 cation of Ungrounded Conductor Color Requirements In paragraph 24.4, an ungrounded conductor must be in contrast to all three of the colors white, gray, and green, not just any one of the three, which the use of or could imply. As such, or is proposed to be changed to and. This wording clarifi cati
14、on also is being proposed in other UL wire and cable standards. e) Clarifi cation of Cable Types Additionally Permitted to be Marked for use as Type NMC-B Cable Paragraph 24.27 has been revised to clarify which cable type (fl at Type UF-B) is permitted to be additionally identifi ed as acceptable fo
15、r use as Type NMC-B cable, and also to revise the permitted conductor ranges from 14 - 6 AWG and 12 - 6 AWG to 14 - 10 AWG and 12 - 10 AWG so as to coincide with the limits for Type NM-B cable in UL 719. f) Miscellaneous Editorial Revisions and Clarifi cations Including Updated Terminology and Stand
16、ards References, and Various Improved Wordings Paragraph 1.1, and Tables 10.1 and 10.2 are revised to use the present terminology of submersible water-pump cable, rather than deep well pump cable. An extraneous reference to the National Electrical Code has been removed from paragraph 1.3. Former par
17、agraph 1.4, and the reference to it in paragraph 1.1, are being deleted as it is not deemed necessary to state that other products may be considered for investigation provided appropriate requirements are applied. References to ASTM Standards in paragraphs 4.3 and 5.1 are updated. Paragraph 5.4 is r
18、evised to remove references to the specifi c applicable sections in UL 83 as UL fi nds it benefi cial to now reference a Standard by name, but not include the specifi c section number when possible. Paragraph 6.1 has been editorially revised and reorganized into two paragraphs (paragraphs 6.1 and 6.
19、2). The title and headings of Table 6.1 have also been editorially revised and reorganized. MARCH 23, 2007SUBJECT 493-2- Copyright Underwriters Laboratories Inc. Provided by IHS under license with ULLicensee=IHS Employees/1111111001, User=Wing, Bernie Not for Resale, 04/02/2007 01:02:21 MDTNo reprod
20、uction or networking permitted without license from IHS -,-,- FOR INTERNAL UL OR CSDS USE ONLY NOT FOR OUTSIDE DISTRIBUTION Paragraphs 7.2.1, 8.3, 8.4, and 14.1 each have been editorially revised in some manner to streamline the wording of the requirements, such as by now referring to a cable contai
21、ning two or three 14 - 6 AWG circuit conductors as a multiple-conductor cable, by removing redundant descriptions of a multi-conductor cable as one which contains two or three circuit conductors with or without a grounding conductor, or by some other similar revision. The requirement in 8.1 that a P
22、VC jacket be snug fi tting and fl exible, yet abrasion resistant, has been removed as this requirement is not evaluated by the Standard. Former paragraph 17.3.1 provided instructions as to which dimensions of mandrels should be stocked so as to have a sufficient number on hand at any time for testin
23、g purposes. This has been deleted as there is no need for the standard to specify the number of mandrels which should be stocked but rather is left up to the manufacturers or test labs discretion. The requirements for the apparatus in 17.3.2 for the Unwinding Test at Low Temperature has been revised
24、 from specifying a dry-ice cabinet or mechanical refrigerator, to instead specify a chamber so as to update the requirement and refl ect present practice. The term drill rod has been replaced by steel mandrel in Section 20 as a drill rod need not be used; rather a steel mandrel of the specifi ed dim
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