1、June 29,2001 1 SUBJECT 2256 OUTLINE OF INVESTIGATION FOR NONMETALLIC SHEATHED CABLE INTERCONNECTS Issue Number 1 JUNE 29,2001 COPYRIGHT O 2001 UNDERWRITERS LABORATORIES INC. 2 SUBJECT 2256 JUNE 29,2001 No Text on This Page JUNE 29. 2001 SUBJECT 2256 3 CONTENTS FOREWORD 6 INTRODUCTION 1 Scope . 7 4 U
2、ndated References CONSTRUCTION 5 General 8 6 Materials . 8 6.1 Current-carrying parts . 8 7 Insulating Materials 8 7.1 Flammability . 8 7.2 Electrical properties . 9 7.3 Thermal properties 1 0 8 Assembly . IO 8.1 Accessibility of current-carrying parts 1 0 9 Spacings 10 PERFORMANCE 10 General 12 11
3、Pull Test . 12 12 Vibration and Temperature Test (Non-Insulation Displacement Terminals) 12 13 Heat Cycling and Vibration Test (Insulation Displacement Terminals) . 13 14 Fault Current Test 14 15 Dielectric Withstand Test 14 16 Flame Test . 15 17 Crush Test . 15 18 Mold Stress Relief Test 15 19 Over
4、load Test 16 20 Temperature Test . 17 21 Resistance to Arcing Test 17 22 Comparative Tracking Index Test . 17 23 Glow Wire Test 17 24 High-Current Arc Resistance to Ignition Test . 18 19 25 Moisture Absorption Resistance Test RATINGS 26 General 19 MARKINGS 27 General 20 4 SUBJECT 2256 JUNE 29,2001 A
5、PPENDIX A Standard for Components. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . , . . . . . . . . . AI 5 SUBJECT 2256 JUNE 29,2001 No Text on This Page 6 SUBJECT 2256 JUNE 29,2001 FOREWORD A. This Outline of Investigation contains basic requ
6、irements for 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
7、or desirable. B. The observance of these requirements by a manufacturer is one of the conditions of the continued coverage of the manufacturer?s 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 Investigat
8、ion if, when examined and tested, it is found to have other features which impair the level of safety contemplated by these requirements. D. A product employing materials or having forms of construction which conflict with specific requirements of the Outline of Investigation cannot be judged to com
9、ply with the Outline of Investigation. A product employing materials or having forms of construction not addressed by this Outline of Investigation may be examined and tested according to the intent of the requirements and, if found to meet the intent of this Outline of Investigation, may be judged
10、to comply with the 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 given with due
11、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 or liability
12、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 and property sha
13、ll be employed in conducting such tests. JUNE 29,2001 SUBJECT 2256 7 INTRODUCTION 1 Scope 1 .I These requirements cover interconnects consisting of mating insulating enclosures which are assembled to nonmetallic sheathed cable and form both a mechanical and electrical connection. This forms a contai
14、ned product for component interconnections for use in exposed or concealed locations in accordance with the National Electrical Code (NEC), ANSVNFPA-70, Article 545, Manufactured Buildings; Article 550, Mobile Homes; Article 551, Recreational Vehicles And Recreational Vehicle Parks, and for tap devi
15、ces in accordance with Article 336, Nonmetallic-Sheathed Cable: Types NM, NMC, and NMS. 1.2 The enclosures of these interconnects are complete without openings and are intended for use without an outlet box or enclosure. 1.3 These requirements cover interconnects intended for use at 600 volts ac or
16、less on 15 and 20 ampere branch circuits wired with Nos. 14 and 12 AWG (2.1 and 3.3 mm2 ) copper conductors, respectively. 1.4 A product that contains features, characteristics, components, materials, or systems new or different from those covered by the requirements in this Outline of Investigation
17、, 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
18、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
19、sion, and implementation of this Outline of Investigation. 2 Glossary 2.1 For the purposes of this Outline of Investigation, the following definitions apply. 2.2 ENCLOSURE - That part of the device that renders inaccessible any or all parts of the device that otherwise presents a risk of electric sh
20、ock, retards propagation of flame initiated by electrical disturbances occurring within , or bot h. 2.3 INSULATION PIERCING OR DISPLACEMENT CONNECTOR - Device intended to establish a connection between the device terminal contacts and one conductor or the interconnection of two or more conductors, b
21、y piercing, boring through, cutting through, removing, displacing, or making ineffective in some other manner the insulation of the conductor or conductors without previous stripping. 2.4 PRESSURE CABLE CONNECTOR -Device intended to establish a connection between the device terminal contacts and one
22、 or more conductors by means of mechanical pressure without the use of solder. a SUBJECT 2256 JUNE 29,2001 3 Units of Measurement 3.1 Values stated without parentheses are the requirement. Values in parentheses are explanatory or approximate information. 4 Undated References 4.1 Any undated referenc
23、e to a code or standard appearing in the requirements of this Outline of Investigation shall be interpreted as referrring to the latest edition of the code or standard. CONSTRUCTION 5 General 5.1 All parts that act as the electrical insulation or enclosure of a device shall be made of an insulating
24、material rated for the particular application. These parts shall not employ hard rubber. 5.2 Vulcanized fiber is not prohibited from being used for insulating washers, separators, and barriers, but not as the sole support of current-carrying parts. The material shall be moisture-resistant in accorda
25、nce with the Moisture Absorption Resistance Test, Section 25. 5.3 A nonmetallic sheathed cable interconnect shall be provided with one or more pressure cable connectors, or insulation piercing or insulation displacement terminals. 5.4 A device shall be capable of being readily installed as intended.
26、 6 Materials 6.1 Current-carrying parts 6.1 .I A current-carrying part shall be of copper or a copper alloy. 7 Insulating Materials 7.1 Flammability 7.1 .I A polymeric material used for electrical insulation or enclosure of current-carrying parts shall have a minimum flame class rating of V-2 in acc
27、ordance with the requirements of the Standard for Tests for Flammability of Plastic Materials for Parts in Devices and Appliances, UL 94. The flame class rating of the material shall be judged at the nominal minimum thickness employed at the walls and barriers in the device which is critical to the
28、functioning of the insulation or enclosure of the device. Exception: A small part meeting all the following requirements is not required to have a flame class rating when: a) its volume does not exceed 2 cm3 (O. 122 cubic inch), and b) its maximum dimension does not exceed 3 cm (I. 18 inches), and c
29、) its location is such that it is unable to propagate flame from one area to another or act as a bridge between a possible source of ignition and other ignitable parts. JUNE 29,2001 SUBJECT 2256 9 Property HWla HAI CTIC 7.2 Electrical properties PLC 3 3 3 7.2.1 A polymeric material used for electric
30、al insulation or enclosure of current-carrying parts shall comply with the requirements in Table 7.1. The material shall be investigated using the specimen thickness employed in the end product or a nominal 3.2-mm (1/8-inch) thickness, whichever is greater. Exception No. I: A polymeric material havi
31、ng a Comparative Tracking Index (CTI) performance level class (PLC) greater than 3 shall comply with the Comparative Tracking Index Test, Section 22. Exception No. 2: A polymeric material having a Hot Wire Ignition (HWI) performance level class (PLC) value greater than that shown in Table 7. I shall
32、 comply with the Glow Wire Test, Section 23. Exception No. 3: A polymeric material used in the enclosure of an interconnect that does not enclose current-carrying parts, or which encloses insulated current-carrying parts where the insulation thickness is greater than O. 71 mm (O. 028 inches), is not
33、 required to comply with the HWI requirement in Table 7. I or the Glow Wire Test, Section 23. Exception No. 4: A polymeric material having a High-Current Arc Resistance to Ignition (HAI) performance level class (PLC) value greater than that shown in Table 7. I shall comply with the High-Current Arc
34、Resistance to Ignition Test, Section 24. Exception No. 5: A polymeric material used in an enclosure that is separated through air by more than 0.8 mm (1/32 inch) from uninsulated current-carrying parts and more than 12.7 mm (1/2 inch) from arcing parts is not required to comply with this requirement
35、. Table 7.1 Electrical ratings of insulating materials a Hot Wire Ignition - Described in the Standard for Polymeric Materials - Short Term Property Evaluations, UL 746A. bHigh Current Arc Resistance to Ignition - Described in the Standard for Polymeric Materials - Short Term Property Evaluations, U
36、L 746A. 746A. Comparative Tracking Index - Described in the Standard for Polymeric Materials - Short Term Property Evaluations, UL 10 SUBJECT 2256 JUNE 29,2001 7.3 Thermal properties 7.3.1 A polymeric material used for electrical insulation or enclosure of current-carrying parts shall have the minim
37、um relative thermal index (RTI) ratings shown in Table 7.2. The material shall be investigated using the specimen thickness employed in the end product or nominal 3.2-mm (1/8-inch) thickness, whichever is greater. Table 7.2 Minimum relative thermal indices of insulating materials I Minimum relative
38、thermal indexa. dearees C I Electrical I Mechanical with impact I Mechanical without impact 80 60 80 a The Relative Thermal Index (RTI) is described in the Standard for Polymeric Materials - Long Term Property Evaluations, UL 7468. 8 Assembly 8.1 Accessibility of current-carrying parts 8.1 .I An int
39、erconnect shall have current-carrying parts protected against exposure to contact by persons when assembled, installed and mated as intended, as determined by the use of the probe shown in Figure 8.1, as described in 8.1.3. 8.1.2 Interconnects shall not have exposed current-carrying contacts during
40、engagement or withdrawal as determined by the use of the probe shown in Figure 8.1, as described in 8.1.3. 8.1.3 The probe is to be used to examine the interconnect. It is to be rotated, changed in configuration, or angled as required (either before, during and after its application) to any position
41、 that is necessary to examine the interconnect and that achieves a usable depth of penetration for the examination. The probe is to be applied with a force of 13.3 N (3 Ib-ft ). 9 Spacings 9.1 The spacings maintained between current-carrying parts of opposite polarity, and between current-carrying p
42、arts and grounded metal parts shall be: a) At least 1.59 mm (1/16 inch) through air and 3.18 mm (1/8 inch) over surfaces for devices rated to a maximum of 125 volts, and b) 3.18 mm (1/8 inch) through air and 4.76 mm (3/16 inch) over surfaces for devices rated greater than 125 volts but to a maximum
43、of 600 volts. JUNE 29,2001 SUBJECT 2256 11 Figure 8.1 Articulate probe with web stop 234 - 25 RAOUS 12 SUBJECT 2256 JUNE 29,2001 PERFORMANCE 10 General 10.1 The performance of devices covered by this standard shall be investigated by subjecting representative production devices to the tests describe
44、d in Sections 10 through 25. 10.2 Unless stated otherwise, tests are to be conducted on each of six representative devices. 11 Pull Test 11.1 As a result of this test, there shall not be any damage to the cable sheath or individual conductor insulation, cracking or breaking of the interconnect, or c
45、able displacement of more than 3.2 mm (1/8 inch) from the interconnect. 11.2 Each of six interconnects with halves mated together is to be assembled onto 0.45-m (18-inch) lengths of cable as intended. The cable conductors are not to be assembled to the interconnect contacts. The outer housing screws
46、 of the interconnects are to be torqued down to 1.13 N.m (IO lb-in). The assemblies are to be hung by the housing in a vertical direction and subjected to a 27.2-kg (60-lb) load for 5 min applied to the cable. Exception No. I: If the interconnects are for use with a range of sizes, then each of thre
47、e interconnects with halves mated together is to be assembled on the minimum wire size as intended and each of the other three interconnects with halves mated together is to be assembled on the maximum wire size. Exception No. 2: Some interconnects snap together or use an alternate means of securing
48、 the outer housing, in lieu of screws. 12 Vibration and Temperature Test (Non-Insulation Displacement Terminals) 12.1 The temperature rise of an interconnect that employs terminals other than the insulation displacement type, when measured at the points described in 12.2, at the completion of the Vi
49、bration Test, shall not be more than 30C (54F) when the device is carrying the current corresponding to the ampacity of the cable size under test. 12.2 Each of six interconnects with halves mated together is to be assembled onto 0.45-m (18-inch) lengths of cable as intended. The interconnects are then to be mounted onto a support rack with the circuits for similar cable sizes connected in series. The support rack is to be constructed of cast-iron angles not smaller than 3.2 by 31.8 by 31.8 mm (1/8 by 1-1/4 by 1-1/4 inch) welded to form a rigid assembly. Mounting holes are to be provided for
