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1、m 7275775 0827020 350 PI Uttderwriters Laboratories 1nc.s Northbrook, illinois*(847) 272-8800 Melville, New Yorke(516) 271-6200 Santa Clara, California (408) 985-2400 Research Triangle Park, North Camlina*(919) 549-1400 Camas, Washington* (360) 817-5500 Subject 1581 (13, 62, 444, 814, 1063, 1263, 12
2、77, 1309, 1424, 1425, 1588, 1655, 1673, 1690, and 2250) (in reply, refer to Subject 1581) 1285 Walt Whitman Road Melville, New York 11747-3081 February 25, 2000 TO: Electrical Council of Underwriters Laboratories Inc. Marine Council of Underwriters Laboratories Inc. Technical Advisory Panel of UL fo
3、r Power Wires and Cables Technical Advisory Panel of UL for Communications PROPOSED EFFECTIVE DATE A not-for-profit organization dedicated to public safety and committed to quality service c “. 9275795 0827023 297 9 Subject 1581 and others -2- February 25, 2000 I SUMMARY OF TOPICS The flame-test per
4、formance and other characteristics of a cord or cable containing a wire covering(s) can be affected by changes in the wire covering(s), so the percent coverage and other construction details of each wire braid and wire serving in a cord or cable are specified in the Procedure and then are checked by
5、 periodic UL Follow-Up Service inspections. Various coverage formulas are in the UL 62, UL 1309, and SU 2588 requirements. A measurement and calculation method is not described in any of the U t requirements that include wire coverings. U t now proposes that formulas and a method for determining wir
6、e braid and serving coverage from measurements on the finished product be placed in the UL 1581 Standard as a new Section 228. Section 228 would be available for reference in place of having a method of determining coverage described in the individual product requirements. COMMENTS DUE: April 7, 200
7、0 I Attached for your review and comment is Appendix A in which UL proposes the wording of the new Section 228 for UL 1581. Appendix B adds retest (flame) and record-keeping information plus calculation examples. Questions regarding interpretation of requirements should be directed to the responsibl
8、e UL Staff. Please see Appendix C to this bulletin regarding designated responsibility for the involved wire and cable product categories. Please note that proposed requirements are of a tentative and early nature and are for review and comment only. Current requirements are to be used to judge a pr
9、oduct until these requirements are published in final form. PROPOSED EFFECTIVE DATE Adoption of a UL 1581 coverage method will not necessitate that UL review or additionally test any currently Listed or Recognized products containing wire coverings. UL proposes that the UL 1581 revisions adding the
10、coverage method be made effective upon publication. RATIONALE Changes in wire braid or serving mass in a cord or cable, and in the number and coverage of such braids and servings, can affect the cord or cable in considerations such as flame-test performance, shielding (electric fields), armoring, an
11、d grounding so UL records details of the wire covering(s) in the Follow-Up Service Procedure at the time that the cord or cable is investigated for Listing or Recognition and then periodically checks for reductions during production. Subject 1581 and others m 7275795 0827022 123 m -3- February 25, 2
12、000 Measurements and calculations are necessary for determining wire braid or serving coverage. Formulas alone are in Section 39 of UL 62 for wire braids and servings (wraps) used as shielding in flexible cords, in Section 3.12 of UL 1309 for the wire-braid armor in marine shipboard cables, and in 3
13、.1 of SU 1588 for the wire-braid grounding component of roof and gutter de-icing cables. UL proposes that UL 1581 include a new Section 228 containing a general method and formulas for determining wire braid and serving coverage. A sentence such as the following could then electively be used to make
14、 reference to UL 1581 in the UL 13, 444, 814, 1063, 1277, 1424, 1425, 1655, 1690, and 2250 Standards and in the SU 1263 Outline: Section 228 of UL 1581 describes a method for determining Wire Braid and Serving Coverage. UL is not proposing that Section 228 or references to it replace the formulas pr
15、esently in UL 62, UL 1309, and SU 1588. In the UL 1673 Standard (space-heating cables), appropriate formulas could be added where Section 11 requires coverage of at least 80 percent for the grounding component, which typically is a wire braid, or reference could be made to Section 228 of UL 1581. Se
16、ction 16 of the UL 817 Standard mentions the use of shielded cords in cord sets but the cord details (including coverage) are in the flexible cord Standard (UL 62), so there is no need for UL 817 to include or reference Section 228. Section 228 is proposed for comment in Appendix A. The proposed for
17、mulas and method use measurements on the finished product. Maintenance of the Procedure record of wire braids, wire servings, and all-metal tape coverings - including changes requiring a flame retest - are discussed in Appendix B with examples of wire braid and serving calculations. Appendix E is ex
18、planatory and will not be printed in UL 1581. IMPACT Adoption of a UL 1581 coverage method will not necessitate that manufacturers take any action to maintain their current Listings or Recognition of wire products. REQUEST FOR COMMENTS ON PROPOSALS Please provide the following: 1. Your comments conc
19、erning the proposed requirements; and 2. Your comments concerning the proposed effective date, should the proposals be adopted. Comments should be made in writing and may be sent by regular mail, fax, or e-mail to the attention of Walter Hoffmann at ULs Melville office, 1285 Walt Whitman Road, Melvi
20、lle, NY 11747-3081. Comments by fax or e-mail should include your name, title, company name, and Post Office address to enable UL to reply by mail where appropriate. Please reference all correspondence to Subject 1581. -,-,- a 9275775 0827023 ObT Subject 1581 and others 4- February 25, 2000 All comm
21、ents should be sent by April 7, 2000, Unless specifically requested to do so, UL will not acknowledge comments indicating concurrence with these proposals. UNDERWRITERS LABORATORIES INC. Standards Engineer Standards Department 2573XCML phone: INT+l 631 271 6200 EXT 22564 fax: INT+l 631 439 6021 e-ma
22、il: WaIter.H REVIEWED BY: AUSTIN O. WETHERELL Staff Engineer Conformity Assessment Services 301 7CMEL phone: INT+l 631 271 6200 EXT 22818 fax: INT+I 631 439 6047 e-mail: SR: LS 1 58 1 BU L. W04; WHH; mc M 9275795 082b5L 275 Subject 1581 and others -Al - February 2000 PROPOSED REQUIREMENTS ARE OF A
23、TENTATIVE AND EARLY NATURE AND ARE FOR REVIEW AND COMMENT ONLY. CURRENT REQUIREMENTS ARE TO BE USED TO JUDGE A PRODUCT UNTIL THESE REQUIREMENTS ARE PUBLISHED IN FINAL FORM. - A P P E N D I X A PROPOSED REQUIREMENTS AND PROPOSED EFFECTIVE DATE FOR THE THIRD EDITION OF THE REFERENCE STANDARD FOR ELECT
24、RICAL WIRES, CABLES, AND FLEXIBLE CORDS, UL 1581 M 9275795 082b952 LOL = Subject 1581 and others -A2- February 2000 311- - 339 221 - 227 Reserved for Future Use WIRE BRAID AND SERVING COVERAGE 228 Measurements and Calculations Section 228 added (date of publication) 228.1 Where a wire covering consi
25、sts of multiple braids or servings (wraps), separate coverage determinations are to be made for each wire braid and serving. Measurements and calculations are specified for braids and sewings of both round and flat wires on round and flat underlying constructions. 228.2 In any one braid or serving,
26、all of the wires are assumed to be of the same metal, the same metal coating (where a metal coating is used), and the same diameter where the wires are round or the same width and thickness where the wires are flat. A wire braid is assumed to be fabricated on a machine using the same number of round
27、 or flat wires in each carrier and the same number of carriers in each direction. 228.3 The method described here uses measurements made on the finished product. For this method, the coverage of each wire braid and serving in a cord or cable is to be determined from calculations using the measuremen
28、ts, formulas, and number of decimal places specified in Table 228.1 for wire-braid constructions and in Table 228.2 for wire servings. 228.4 For a wire braid, the number of plaits laid in one direction along 1 inch or 20 millimeters of the axial length of the wire braid is to be counted to the neare
29、st tenth of a plait by means of a standard braid counter (see 228.5) at three places that are at least 2 inches or 50 mm apart in any 12-inch or 300- mm section in the center 3 fi or 1 m of a straight 5-ft or 1500-mm specimen of the wire-braid-covered conductor, assembly, or core. The average of the
30、 three measurements made in inches is to be expressed to the nearest tenth of a plait and taken as P the number of picks per inch for that wire braid. The average of the three measurements made in millimeters is to be divided by 20. The result expressed to the nearest hundredth of a plait is to be t
31、aken as P the number of picks per millimeter for that wire braid. 228.5 Where a braid counter is not available, the count is to be made along 6 inches or 150 mm of the braid at one place in the 12-inch or 300-mm section. This measurement in inches is to be divided by 6. The result expressed to the n
32、earest tenth of a plait is to be taken as P the number of picks per inch for that wire braid. This measurement in millimeters is to be divided by 150. The result expressed to the nearest hundredth of a plait is to be taken as P the number of picks per millimeter for that wire braid. -,-,- 7275775 D2
33、b53 D g 8 I I Subject 1581 and others -A3- Flat , February 2000 Table 228.1 Coverage calculations for a wire braid - - Shape of a braid wire Round Calculations Formulas The notes to this table specify how to determine the value of each parameter tc enter in the formulas shown in this column. Use the
34、 formulas in the sequence shown reading down this column. Use of other formulas is appropriate where the formulai are applicable, agreed upon. and recorded. Example in Appendix B Note that this column and the txamples an shown only for info and will not be Dnnted in UL 1581. SHAPE Number of decimal
35、places Makeup of construction under braid Name 3 Nearest degree 3 tana=2x3.1416xP(D + 2dYC Braid angle (a) Determine a (arctan) ROUND Determine sin a 1, 3, 4, or more conductors i r other found elements or assemblies ir an entire round cable core 1 -way coverage (F) F = (N x P x d)/sin a 3 1 or 2 or
36、 more twisted pairs 2-way (total) coverage (GI G = 2F - F2 3 or I parallel or twisted pair of conductors Ir other round elements ?Ilers are included. air is round. Percent total coverage (K) Nearest percent K = 700 x G Substitute these formulas: Flat tan a = 2 x 3.1416 x P(D + 2t)/C f = (N x P x w)/
37、sin a Same formulas substituting D for D. eq 2 Round 3 )araIlel or twisted pair) of ionductors or other round elements :Ilers are not included. lair is not round. Same formulas substituting D for O. eq 4 notes on next page -,-,- Subject 1581 and others 9275775 082b754 TA4 9 -A4- February 2000 C = to
38、tal number of carriers in the wire braid. d = diameter of one round braid wire to the nearest 0.0001 inch or 0.001 rnm. D = diameter of the round assembly under the wire braid measured to the nearest 0.001 inch or 0.1 mm. De,., = equivalent diameter over the two parallel or twisted round coaxial ele
39、ments or insulated conductors under the wire braid determined to the nearest 0.001 inch or 0.1 mm by means of a diameter tape or by dividing the measured circumference of the flat pair by 3.1416 (n). N = number of round or flat wires in one carrier of the wire braid. P = picks per inch or picks per
40、millimeter determined as indicated in 228.4 and 228.5. t = thickness of one flat braid wire to the nearest 0.001 inch or 0.1 mm. w = width of one flat braid wire to the nearest 0.001 inch or 0.1 mm -,-,- Subject 1581 and others February 2000 Table 228.2 Coverage calculations for a wire serving (spir
41、al shield or reverse spiral shield) HAPE akeup of construction ider serving (wrap) IOUND , 3, 4, or more conductors ir other round elements or assemblies or i n entire round cable core or ! or more twisted pairs or parallel or twisted pair of conductors or ither round elements :Ilers are included. a
42、ir is round. FLAT Parallel or twisted pair(s) of :onductors or other round elements Filler! are not included. Pair is not round. ;hapa of a living wire Round Fiat Round flat Name Serving angle (4 Coverage (5) Calculations Formulas he notes to this table specify hou Io determine the value of each ara
43、meter to enter in the formulas shown in this column. Ise the formulas in the sequence :how reading domi this COIUN. Use o i other fornulas is appropriate where the formulas are applicable, agreed upon, and recorded. tan a = 3.1416 x (0 + d)/L Determine a (arctan) Determine cos a 6 = (H x dM3.1416 x
44、(D + d) x WS a K = 1OOx B Percent coverage (K) Substitute these formulas: tan a = 3.1416 x (D + t)L Number of decimal places 3 Nearest degree 3 3 Nearest percent B = (H x w)43.1416 x (D + t) x cos a Same formulas substituting D for D. eq Same formulas substituting D for D. eq ixample in ippendix B V
45、ote that this column and the bxamples re shown only for info and vi/ not be grinted in UL 1587. 5 6 7 8 = 9275795 082b95b 857 Subject 1581 and others -A6- February 2000 d = diameter of one round serving wire to the nearest 0.0001 inch or 0.001 mm. D = diameter of the round assembly under the wire se
46、rving measured or calculated to the nearest 0.001 inch or 0.1 mm. Deq = equivalent diameter over the two parallel or twisted round coaxial elements or insulated conductors under the wire sewing determined to the nearest 0.001 inch or 0.1 mm by means of a diameter tape or by dividing the measured cir
47、cumference of the flat pair by 3.1416 (n). H = number o f round or flat wires in the wire sewing. i = lay length to the nearest 0.01 inch or 0.1 mm along the cord or cable axis for one complete turn of a serving wire around the round or flat construction under the serving. t = thickness o f one flat
48、 sewing wire to the nearest 0.001 inch or 0.1 mm. w = wldth of one flat sewing wire to the nearest 0.001 inch or 0.1 mm. 229 - 239 Reserved for Future Use -,-,- 7275795 082b757 793 = Subject 1581 and others -61 - February 2000 METAL SHIELDS AND COVERINGS RELATIVE TO FLAME TEST PERFORMANCE This discu
49、ssion and the calculation examples will not be printed in UL 1581 Effect of Changes Electrostatic and other metal shields and coverings in a cord or cable conduct heat and so affect the performance of the cord or cable in each of the required flame tests. Where there is compliance with a flame test and the combus