1、May 24,2002 1 SUBJECT 1588 OUTLINE OF INVESTIGATION FOR ROOF AND GUTTER DE-ICING CABLE UNITS Issue Number 4 MAY 24, 2002 COPYRIGHT O 1993, 2002 UNDERWRITERS LABORATORIES INC. 2 SUBJECT 1588 MAY 24,2002 No Text on This Page MAY 24. 2002 SUBJECT 1588 3 CONTENTS FOREWORD 4 INTRODUCTION 1 Scope . 5 4 Un
2、dated References CONSTRUCTION 5 Heating Conductors . 6 6 Grounding Component . 6 7 Outer Jacket . 7 8 Nonheating Leads . 7 9 Installation Components . 8 PERFORMANCE 10 General . 8 11 Heating Cable Tests 8 11 . 1 Crushing test . 8 11.2 Impact test 11.3 Abrasion tes 11.4 Cold-bend test 11.5 Flame test
3、 . 11 12.1 Installation test . 11 12.2 Input test 13 12.3 Temperature test . 13 12.4 Thermal protection . 13 12.5 Dielectric voltage-withstand test 13 12.6 Ground-fault current test 14 12.7 Lead pull-out test . 15 12.8 Weatherometer tests . 15 12.9 Tension test . 15 12.1 O Severe-use test . 15 12.1
4、1 Splice-insulation/insulation-resistance test 16 12.1 2 Splice-enclosure mechanical evaluation 16 12 Complete-System Tests 11 MARKINGS 13 Cable Unit . 16 INSTRUCTIONS 14 Installation Instructions 17 4 SUBJECT 1588 MAY 24,2002 FOREWORD A. This Outline of Investigation contains basic requirements for
5、 products covered by Underwriters Laboratories Inc. (UL) under its Follow-Up Service for this category within the limitations given below and in the Scope section of this Outline of Investigation. They are subject to revision as further experience and investigation may show is necessary or desirable
6、. B. The observance of these requirements by a manufacturer is one of the conditions of the continued coverage of the manufacturers product. C. A product which complies with the text of this Outline of Investigation will not necessarily be judged to comply with the Outline of Investigation if, when
7、examined and tested, it is found to have other features which impair the level of safety contemplated by these requirements. D. A product that contains features, characteristics, components, materials, or systems new or different from those covered by the requirements in this Outline of Investigatio
8、n, and that involves a risk of fire or of electric shock or injury to persons shall be evaluated using appropriate additional component and end-product requirements to maintain the level of safety as originally anticipated by the intent of this Outline of Investigation. A product whose features, cha
9、racteristics, components, materials, or systems conflict with specific requirements or provisions of this Outline of Investigation does not comply with this Outline of Investigation. Revision of requirements shall be proposed and adopted in conformance with the methods employed for development, revi
10、sion, and implementation of this Outline of Investigation. E. UL, in performing its functions in accordance with its objectives, does not assume or undertake to discharge any responsibility of the manufacturer or any other party. The opinions and findings of UL represent its professional judgement g
11、iven with due consideration to the necessary limitations of practical operation and state of the art at the time the Outline of Investigation is processed. UL shall not be responsible to anyone for the use of or reliance upon this Outline of Investigation by anyone. UL shall not incur any obligation
12、 or liability for damages, including consequential damages, arising out of or in connection with the use, interpretation of, or reliance upon this Outline of Investigation. F. Many tests required by the Outline of Investigations of UL are inherently hazardous and adequate safeguards for personnel an
13、d property shall be employed in conducting such tests. MAY 24, 2002 SUBJECT 1588 5 INTRODUCTION 1 Scope 1.1 This outline covers roof and gutter de-icing cable units intended for permanent connection. These cable units are intended for use in accordance with Article 426 of the National Electrical Cod
14、e, NFPA 70. 2 Components 2.1 Except as indicated in 2.2, a component of a product covered by this outline shall comply with the requirements for that component. 2.2 A component is not required to comply with a specific requirement that: a) Involves a feature or characteristic not required in the app
15、lication of the component in the product covered by this outline; or b) Is superseded by a requirement in this outline. 2.3 A component shall be used in accordance with its rating established for the intended conditions of use. 2.4 Specific components are incomplete in construction features or restr
16、icted in performance capabilities. Such components are intended for use only under limited conditions, such as certain temperatures not exceeding specified limits, and shall be used only under those specific conditions. 3 Units of Measurement 3.1 Values stated without parentheses are the requirement
17、. Values in parentheses are explanatory or approximate information. 4 Undated References 4.1 Any undated reference to a code or standard appearing in the requirements of this outline shall be interpreted as referring to the latest edition of that code or standard. 6 SUBJECT 1588 MAY 24,2002 CONSTRUC
18、TION 5 Heating Conductors 5.1 The heating conductors of other than a metallic-sheathed roof and gutter de-icing cable shall be insulated with a compound acceptable for use at 75C (167F) or higher in dry locations and 60C (140F) or higher in wet locations. The average thickness of the insulation shal
19、l not be less than 0.762 mm (0.030 inch) with a minimum of 0.686 mm (0.027 inch) at any one point. Magnesium oxide suitable for the purpose is acceptable as an insulating compound for use with metallic sheathed cables. 6 Grounding Component 6.1 The heating section of a roof and gutter de-icing cable
20、 shall be provided with a grounding component which consists of a metallic sheath or a metallic braid. In the case of a metallic braid, provision shall be made for connecting the braid to the branch-circuit grounding means by a means such as: a) A grounding lead 14 AWG minimum bare or green insulate
21、d copper wire; b) A fitting that surrounds the cable and mechanically secures the braid; or c) A lug to be crimped onto the pigtailed braid and then secured to a grounding screw in the supply junction box. If the heating section consists of more than one conductor, the grounding component may be inc
22、orporated on each conductor or all conductors may be enclosed within a common sheath or braid. The grounding component shall have an ampacity not less than that of 18 AWG copper conductor. 6.2 If the grounding component consists of a braid, it shall provide at least 50 percent coverage as determined
23、 according to the following formula: Percent coverage = 100 (2F - F2) in which: F= E; (OIFII) sina a - Angle of braid with axis of cable MAY 24. 2002 SUBJECT 1588 7 2nDP Tana= - C d - Diameter of individual braid wires in inches C - Number of carriers D - Diameter under shield in inches N - Number o
24、f wires per carrier P - Picks per inch 7 Outer Jacket 7.1 A weather-resistant jacket shall be provided over a metal braid used as a grounding component. Exception: An outerjacket is not required to be provided over a metal braid in units which demonstrate acceptable performance after being subjected
25、 to long term environmental exposure, in addition to complying with the performance requirements. 8 Nonheating Leads 8.1 The heating section shall be connected to nonheating leads of a weather-resistant type. Instructions provided with each unit shall instruct the installer to physically protect the
26、 nonheating leads by installing them in a rigid metal or nonmetallic raceway. 8.2 Heating conductors that are intended for use as nonheating leads as well shall be investigated for use as leads. At any point within the junction box in which such leads are connected to branch-circuit wiring, the temp
27、erature rise during the temperature test (see 12.3.1) of the cable unit shall not exceed 35C (63F). If during the temperature test any point within the junction box attains a temperature higher than 60C (140“F), the installation instruction in 14.l(b) shall include “For supply connections, use wires
28、 suitable for at least . “C (.OF).“ or an equivalent statement with the temperature value as follows: 8 SUBJECT 1588 MAY 24,2002 Over 60C (140F) but not over 75C (167F) Over 75C (167F) but not over 90C (194F) I Test temperature in iunction box I Temperature to use in instruction I 75C (167F) 90C (19
29、4F) Marked rating in volts 95 or less Over 95 but not over 120 Over 120 but less than 220 At least 220 but not over 240 9.1 Suitable installation components shall be available for each system for proper installation. Component parts constructed of metal shall be corrosion resistant. Exposed nonmetal
30、lic component parts shall be constructed of weather resistant materials. V The marked voltage (the highest value of a range if so marked) 120 The marked voltage (the highest value of a range if so marked) 240 PERFORMANCE 10 General 10.1 In determining the performance acceptability, a roof and gutter
31、 de-icing cable shall comply with both heating cable and complete system tests. Unless otherwise indicated, the ambient temperature is to be 25 I5“C (77 I9“F) for the tests. Exception: Cable which has been previously found to comply with equivalent requirements may be exempt from applicable portions
32、 of the test program. 10.2 For test purposes, the voltage that is mentioned as “V“ in 12.3.1, 12.5.1, and 12.10.1 is to be as specified in Table 10.1. Table 10.1 Test voltage 11 Heating Cable Tests 11.1 Crushing test 11.1.1 The heating section of a roof and gutter de-icing cable shall demonstrate re
33、sistance to crushing equal to 907 kg (2000 pounds). Samples of the cable are to be placed separately in a compression machine between flat, rigid steel plates mounted horizontally and parallel to each other. As shown in Figure 11.1, the dimensions of each plate are to be 51 mm (2 inches) in the hori
34、zontal direction (width) parallel to the longitudinal axis of the cable and 51 mm (2 inches) or more in the horizontal direction perpendicular to the longitudinal axis of the cable. The upper plate is to move down at the rate of 12.7 mm (1/2 inch) per minute and the lower plate is to be stationary.
35、The crushing is to be continued until either of the conductors electrically contacts grounding component or one of the steel plates or the other conductor, as indicated by a means such as a low voltage buzzer. The force at electrical contact is to be recorded and the average of ten readings is to be
36、 noted. If the heating section is of two conductors, it is to be twisted for 180 degrees so as to cause the conductors to overlap when performing this test. As shown in Figure 11 .I, the twist is to extend throughout the full 51 mm (2-inches) width of the steel plates. MAY 24, 2002 SUBJECT 1588 9 Lo
37、 Figure 11.1 Crushing test wer plate S3524 11.2 Impact test 11.2.1 The heating section of a roof and gutter de-icing cable shall resist an impact of at least 13.6 J (IO foot-pounds) on a flat surface and at least 6.8 J (5 foot-pounds) on a 19.1 mm (3/4-inch) drill rod without causing more than two f
38、ailures in either case. Samples of the heating section are to be subjected to the impact of a free falling flat faced 31.8 mm (I-1/4 inch) diameter cylindrical 2.3 kg (5 pounds) steel weight. Ten trials per specimen are to be made with the weight dropped from a specific height. For each trial, a new
39、 section of each specimen is to be laid on a flat surface and on a 19.1 mm (3/4 inch) diameter drill rod. The weight is to be dropped from increasing heights in increments of 152 mm (1/2 foot), starting at 152 mm (112 foot) elevation. The height is to be increased until at least one but no more than
40、 two failures of the insulation occurs in ten trials. Failure is defined as either a rupture of the insulation through which the conductors are visible, or electrical contact of the conductors to the equipment or to each other is noted, as indicated as by a 3 watt neon lamp connected in series with
41、the conductor under test, the metallic braid, and 120 volts ac supply. 10 SUBJECT 1588 MAY 24,2002 11.3 Abrasion test 11.3.1 The heating section of a roof and gutter de-icing cable shall resist at least 2500 cycles of abrasion. Six straight untwisted specimens of the heating cable, with any cosmetic
42、 overall jacket removed, are to be attached to a horizontal reciprocating table while the table is at one end of its travel. The other end of each specimen is to be attached to a weight that exerts 3/4 of a Newton (pound force). Each specimen is to be laid over a 1/4 cylinder to whose outer surface
43、an unused sheet of grade 1/2 (medium) emery cloth is attached. The radius of the surface of the emery cloth is to be 88.9 mm (3.5 inches). Refer to Figure 11.2. The longitudinal axis of the cylinder is to be horizontal and perpendicular to each of the vertical planes that contain the specimens as th
44、ey move and are abraded by the emery cloth. The table is to be started in its horizontal reciprocating motion at the rate of approximately 30 cycles per minute, each cycle consisting of one complete back and forth motion with a stroke of approximately 159 mm (6-1/4 inches). The table is to be stoppe
45、d every 50 cycles and the emery cloth is to be slightly shifted to one side so that in subsequent cycles, each specimen is abraded by a fresh surface of the cloth. The cable is not acceptable if the metal grounding braid is exposed unless the grounding braid has been evaluated and found acceptable f
46、or exterior/interior use. In constructions with no outer jacket, the cable is not acceptable if the strands of the grounding braid are opened. Figure 11.2 Abrasion test Reciprocatin table with 6-1/4 in. ?159mm) stroke A (Emery cloth A 1 rter cylinder with us of 3-1/2 in. (89mm) V Cable under test u
47、S3525 11.4 Cold-bend test 11.4.1 The nonmetallic parts (any cosmetic jacket is to be removed) of the heating section of a roof and gutter de-icing cable shall not show any surface or internal cracks when a specimen that is not over 15.9 mm (0.625 inch) in diameter or in length of minor axis and that
48、 has been subjected, for 4 hours to a temperature of -30 SOC (-22 I3.6“F), is wound six complete turns (flatwise in the case of a flat cable) MAY 24, 2002 SUBJECT 1588 11 Braided with jacket Bra id ed around a mandrel with a diameter as indicated in Table 11.1 while the mandrel and specimen are at t
49、he test temperature. Larger specimens are to be wound for one complete turn around the mandrel. The winding is to be done at a uniform rate of 3 seconds per turn and successive turns are to be in contact with one another. Table 11 .I Mandrel diameter 8 5 Type of cable Mandrel diameter = measured diameter or length of minor axis of finished cable times the multiplying factor 8 or 5 as atmrowiate from below 11.5 Flame test 11.5.1 The heating section of a roof and gutter de-icing cable shall comply with the VW-1 (Vertical-Specimen) Flame Test located within the Reference
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