1、BRITISH STANDARD AEROSPACE SERIES BS 2G 223: 1989 Specification for Screen terminating devices for aircraft electric cables UDC 629.7.064.5:621.315.684:621.315.2:001.4:620.1BS2G223:1989 This British Standard, having been prepared under the directionof the Aerospace Standards Committee, was published
2、 under the authority ofthe Board of BSI and comes intoeffect on 31August1989 BSI 12-1999 The following BSI references relate to the work on this standard: Committee reference ACE/6 Draft for comment 87/75413 DC ISBN 0 580 17149 3 Committees responsible for this British Standard The preparation of th
3、is British Standard was entrusted by the Aerospace Standards Committee (ACE/-) to Technical Committee ACE/6, upon which the following bodies were represented: British Airways BEAMA Ltd. British Cable Makers Confederation British Rubber Manufacturers Association Civil Aviation Authority Electronic Co
4、mponents Industry Federation Ministry of Defence National Supervising Inspectorate Society of British Aerospace Companies Limited Amendments issued since publication Amd. No. Date of issue CommentsBS2G223:1989 BSI 12-1999 i Contents Page Committees responsible Inside front cover Foreword ii 1 Scope
5、1 2 Definitions 1 3 Identification and declaration 1 4 Design requirements 1 5 Tests 2 5.1 General requirements 2 5.2 Type tests 2 5.3 Supplementary type tests 4 5.4 Production control tests 4 5.5 User control tests for joints 4 Figure 1 Voltage drop test 3 Figure 2 Tensile test 6 Figure 3 Vibration
6、 test 6 Table 1 Test sequence and number of specimens for type tests 3 Table 2 Supplementary type tests 5 Publications referred to Inside back coverBS2G223:1989 ii BSI 12-1999 Foreword This revision of this British Standard has been prepared under the direction of the Aerospace Standards Committee a
7、t the request of aircraft operators to define the requirements of screen terminating devices for the purpose of finishing the braids, providing a low resistance path to earth or for commoning braids by direct interconnection or across an in-line connection. It supersedes BSG223:1977 which is withdra
8、wn. The standard deals with the performance of the joints and details the suitability of devices for the various forms of screen construction currently in use. It is essential that equipment for installing thermally formed screen terminating devices in remotely high risk areas defined as Zone 2 in B
9、S5345 be certified to the requirements of the type of protection N of BS5345 or equivalent. A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards are responsible for their correct application. Compliance with a British Standard does not
10、 of itself confer immunity from legal obligations. Summary of pages This document comprises a front cover, an inside front cover, pagesi andii, pages1 to6, an inside back cover and a back cover. This standard has been updated (see copyright date) and may have had amendments incorporated. This will b
11、e indicated in the amendment table on the inside front cover.BS2G223:1989 BSI 12-1999 1 1 Scope This British Standard specifies the requirements for the design and testing of insulated and uninsulated screen terminating devices for general purpose screened electrical cables or wires for aircraft in
12、the temperature ranges defined in the relevant cable specifications. The devices are intended for the purpose of pigtailing the cable screen where a low resistance path to earth or linking of screens is required, or for the purpose of dead-ending. The devices are not intended for use on radio freque
13、ncy (R.F.) cables. The types of screens in common use are as follows: a) circular stranded braid; b) flat stranded braid; c) spiral screen (circular strands). Where the design of the device excludes its use on a particular type or types of screen this will be declared. NOTEThe titles of the publicat
14、ions referred to in this standard are listed on the inside back cover. 2 Definitions For the purposes of this British Standard the definitions contained in BSG178-1, and the following, apply. 2.1 application tools the tools used in forming mechanically formed and thermally formed joints NOTESee2.2 a
15、nd2.3. 2.2 mechanically formed joint a permanent connection between the cable screen and pigtail wire achieved by mechanical deformation of the device by full cycle compression tooling 2.3 thermally formed joint a permanent connection between the cable screen and pigtail wire achieved by the control
16、led application of heat 2.4 insulation support the part of a device into which the insulation of the pigtail wires or sheath of the screened cable is placed and which by reforming supports the insulation 2.5 dead-ending a method of finishing a screen where no connections are to be made 2.6 pigtailin
17、g the formation or attachment of a wire or wires for the purpose of remake connection of the screen. Such wires are also known as ground wires, bonding wires, earth wires or jumper wires 2.7 screened cable a cable in which the conductor and insulation are screened by one or more metallic layers to r
18、educe electromagnetic interference between adjacent circuits. It is sometimes referred to as shielded cable 2.8 heating device an application tool designed to apply controlled heat to produce a thermally formed joint 3 Identification and declaration A declaration shall be made in the form of a decla
19、ration of design and performance as specified in BS3G100. The performance parameters of devices supplied to this specification shall be confirmed by the tests required by this specification. They shall be described in the following detail as a minimum: a) method of jointing (mechanical or thermal);
20、b) description of device (single- or multiple-part construction); c) insulation (uninsulated, pre-insulated, or post-insulated); d) temperature range; e) type or types of screen accommodated; f) cable types and sizes; g) pigtail wire size accommodated; h) colour coding or identification, where appli
21、cable; i) application tools. 4 Design requirements 4.1 The protective treatment and surface finish shall be of such a quality that the completed joint complies with the test requirements of this standard. 4.2 The design of the device shall be such that correct engagement of the screen and pigtail wi
22、res in the joint can be readily inspected after completion.BS2G223:1989 2 BSI 12-1999 4.3 Pre-insulated devices shall be insulated over their outer surface. The insulation shall remain in its intended position on the device before and after installation. 4.4 Post-insulated devices shall be so design
23、ed that the post-insulation remains in position over the joint after installation. It shall be compatible with the temperature requirements of the device. 4.5 Where possible, for devices intended for use with tools having interchangeable dies, colour or other means of coding should be applied to bot
24、h the devices and the crimping dies. In addition, the completed joint should, where practicable, be marked in accordance with the code declared in the approved drawings to identify the size of the die. 4.6 The approving authority 1)shall be provided with certified drawings containing the following i
25、nformation. a) The limiting dimensions, material specifications, hardness and finish of the devices, jointing compounds (where used) and the sizes and types of cable for which the devices are suitable. b) In respect of the associated installation tools, the limiting dimensions for: 1) mechanically f
26、ormed joints: dies, tool settings, locators or positioners; 2) thermally formed joints: heater and reflector references, and operating procedures appropriate to the various combinations of conductors and components. c) The code of identification marks, so far as applicable. d) The suggested method o
27、f gauging. Any changes in any of these features shall be notified to the approving authority, who may require a complete series of tests before accepting any further devices. 5 Tests 5.1 General requirements Tests shall be made to prove compliance with all the requirements of this standard. Four kin
28、ds of tests are specified. 5.2 Type tests NOTEIn Figure 1, Figure 2 and Figure 3, the illustrations showing the use of ring terminals are purely typical and other methods of ensuring correctly prepared conductors may be authorized by the relevant Approving Authority. 5.2.1 Test conditions. Unless ot
29、herwise specified, all tests shall be performed at a temperature of20 5 C, at an air pressure of1 060mbar 2)maximum and a relative humidity not greater than75%. All joints used in the type test should be stored under these conditions for a period of48h before testing. 5.2.2 Type test sequence and nu
30、mber of specimens 5.2.2.1 Tests shall be made to demonstrate the satisfactory performance of each combination of device and screen type for which approval is sought. For each combination, the largest and smallest cable screen envelope shall be tested. 5.2.2.2 The tests shall be made in the order sho
31、wn inTable 1 on 32 specimens meeting the requirements of5.2.3. 5.2.2.3 Specimens shall comprise a length of screened cable terminated at each end by the screen terminating device and including pigtail wires as shown inFigure 1. 1) For devices for use on aircraft subject to British civil or military
32、airworthiness requirements, the approving authorities are the Civil Aviation Authority (through a design authority approved by the Authority) and the Procurement Executive, Ministry of Defence, respectively. Before granting approval the approving authority may require evidence that devices conformin
33、g to the drawings will satisfy the test requirements of this standard. Test Clause Type tests 5.2 Supplementary type tests 5.3 Production control tests by the manufacturer 5.4 Users control tests 5.5 2) 1 mbar =10 2N/m 2=10 2Pa.BS2G223:1989 BSI 12-1999 3 The manufacturer may prepare and inspect an a
34、dditional eight specimens and hold these as a reserve group. Should any single failure occur during not more than one test sequence, that test may be repeated with the reserve group. The requirements of this British Standard shall be satisfied if the individual failure is not repeated in the reserve
35、 group. 5.2.2.4 Specimens shall be numbered on an area not involved in the installation operation. Table 1 Test sequence and number of specimens for type tests 5.2.3 Inspection 5.2.3.1 The device and tools shall be inspected for compliance with the approved drawings. It shall be verified that the ca
36、bles have been released to the appropriate specifications and that stripping has been done satisfactorily. 5.2.3.2 Dies and positioners, or heaters and reflectors, used in forming the joints shall be inspected to ensure that they conform to the approved drawings. 5.2.3.3 Mechanically formed joints s
37、hall be visually inspected for: a) correct combination of cable, tool and device; b) correct die mark, where applicable; c) correctness of form and location of crimp deformation; d) freedom from fracture, rough or sharp edges and flash; e) correct insertion of all pigtail conductor strands in the fe
38、rrule or sleeve; f) freedom in the insulation from flash, pinholes, bubbles, cracks, inclusions and other defects; g) absence of damage to the complete assembly. 5.2.3.4 Thermally formed joints shall be inspected for: a) correct combination of cable and devices; b) proper centring of device; c) evid
39、ence of uniform heating of the sleeve and, where applicable, correct flow of the solder; d) absence of damage to pigtail or insulation of pigtail or insulation of screened cable; e) freedom in the insulation from flash, pinholes, bubbles, cracks, inclusions and other defects; f) absence of damage to
40、 the complete assembly. 5.2.4 Voltage drop test. When measured with a test current of 1 A and open circuit voltage of2.5V d.c. across the specimen, the voltage drop shall be not greater than that listed below. 5.2.5 Salt mist test. After exposure to salt mist in accordance with BS2011-2.1Kb, severit
41、y 1, the specimens shall be subjected to and shall pass the voltage drop tests listed in5.2.4. 5.2.6 Tensile test 5.2.6.1 Each specimen shall be tested in accordance with the requirements and in the manner shown inFigure 2 and at a constant rate of traverse of25mm/min to50mm/min. No specimen shall b
42、reak. 5.2.6.2 Specimens 1 to 8 shall be tested as formed, after conditioning as described in5.2.1. 5.2.6.3 Specimens 9 to 16 shall be tested after the following conditioning, with immediate transfer between each condition. Store in an oven at maximum designed operating temperature 5 C for not less t
43、han2h. All dimensions are in millimetres. NOTE 1Direction of pigtails to be in accordance with the manufacturers recommendation. NOTE 2Prepared conductors may be used in place of ring tongue terminals. Figure 1 Voltage drop test Clause Test Test specimen numbers 5.2.3 5.2.4 5.2.6 5.2.4 5.2.6 5.2.5 5
44、.2.7 5.2.4 Inspection Voltage drop (as formed) Tensile (as formed) Voltage drop (after thermal shock) Tensile (after thermal shock) Salt mist Vibration Voltage drop 1 to 32 1 to 32 1 to 8 9 to 16 9 to 16 17 to 24 24 to 32 17 to 32 NOTESpecimens should be assembled using size 20 pigtail wires on 12 s
45、pecimens and size 24 wire on the other 12 specimens. An equal number of tests should be carried out on each wire size. Specimens using size 24 pigtail wires may be made up with two pigtails if approval is sought. Pigtail wire sizeno. Voltage drop A-B (Figure 1) inclusive maximum mV 24 20 14 10BS2G22
46、3:1989 4 BSI 12-1999 Immerse in iced water for not less than1h. Transfer to the oven and store at maximum designed operating temperature for not less than2h. Immerse in iced water for not less than1h. Transfer to the oven and store at maximum designed operating temperature for not less than2h. Immer
47、se in iced water for not less than18h. Transfer to the oven and store at maximum designed operating temperature for not less than2h. Immerse in iced water for not less than1h. Transfer to the oven and store at maximum designed operating temperature for not less than2h. Immerse in iced water for not
48、less than1h. Allow to regain room temperature and condition as in5.2.1. 5.2.7 Vibration test 5.2.7.1 A suggested method of mounting the device for the vibration test is shown inFigure 3. 5.2.7.2 The specimens shall be subjected to the vibration resonance search test detailed in BS3G100-2-3.1. In the
49、 event of resonance being observed the provisions of BS3G100 shall be applied. 5.2.7.3 The specimens shall be subjected to the vibration endurance tests detailed in the relevant clauses of BS 3G 100-2-3.1. 5.2.7.4 At the conclusion of the resonance search test (and at the conclusion of any resulting10h endurance test should this be necessary) the specimens shall be visually examined. There shall be no sign of loosening of parts or undue wear which would impair performance. 5.3 Supplementary type tests 5.3.1 The following additional type tests (seeTable
