1、raising standards worldwideNO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBSI Standards PublicationBS EN 3475-605:2010Aerospace series Cables,electrical, aircraft use TestmethodsPart 605: Wet short circuit testBS EN 3475-605:2010 BRITISH STANDARDNational forewordThis British S
2、tandard is the UK implementation of EN 3475-605:2010.It supersedes BS EN 3475-605:2002 which is withdrawn.The UK participation in its preparation was entrusted to TechnicalCommittee ACE/6, Aerospace avionic electrical and fibre optictechnology.A list of organizations represented on this committee ca
3、n beobtained on request to its secretary.This publication does not purport to include all the necessaryprovisions of a contract. Users are responsible for its correctapplication. BSI 2010ISBN 978 0 580 65533 3ICS 49.060Compliance with a British Standard cannot confer immunity fromlegal obligations.T
4、his British Standard was published under the authority of theStandards Policy and Strategy Committee on 31 August 2010Amendments issued since publicationDate Text affectedBS EN 3475-605:2010EUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN 3475-605 July 2010 ICS 49.060 Supersedes EN 3475-605:2002
5、English Version Aerospace series - Cables, electrical, aircraft use - Test methods - Part 605: Wet short circuit test Srie arospatiale - Cbles lectriques usage aronautique - Mthodes dessais - Partie 605 : Essai de court-circuit humide Luft- und Raumfahrt - Elektrische Leitungen fr Luftfahrtverwendun
6、g - Prfverfahren - Teil 605: Verhalten nach Kurzschlu, feucht This European Standard was approved by CEN on 27 February 2010. CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard w
7、ithout any alteration. Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the CEN Management Centre or to any CEN member. This European Standard exists in three official versions (English, French, German). A version in any other langu
8、age made by translation under the responsibility of a CEN member into its own language and notified to the CEN Management Centre has the same status as the official versions. CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estoni
9、a, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom. EUROPEAN COMMITTEE FOR STANDARDIZATION COMIT EUROPEN DE NORMALISATION EUROPI
10、SCHES KOMITEE FR NORMUNG Management Centre: Avenue Marnix 17, B-1000 Brussels 2010 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Members. Ref. No. EN 3475-605:2010: EBS EN 3475-605:2010EN 3475-605:2010 (E) 2 Contents Page Foreword 31 Scope 42 Normati
11、ve references 43 Specimen requirements 44 Preparation of specimen .55 Apparatus .66 Method 87 Requirements .9BS EN 3475-605:2010EN 3475-605:2010 (E) 3 Foreword This document (EN 3475-605:2010) has been prepared by the Aerospace and Defence Industries Association of Europe - Standardization (ASD-STAN
12、). After enquiries and votes carried out in accordance with the rules of this Association, this Standard has received the approval of the National Associations and the Official Services of the member countries of ASD, prior to its presentation to CEN. This European Standard shall be given the status
13、 of a national standard, either by publication of an identical text or by endorsement, at the latest by January 2011, and conflicting national standards shall be withdrawn at the latest by January 2011. Attention is drawn to the possibility that some of the elements of this document may be the subje
14、ct of patent rights. CEN and/or CENELEC shall not be held responsible for identifying any or all such patent rights. This document supersedes EN 3475-605:2002. According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement th
15、is European Standard: Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerlan
16、d and the United Kingdom. BS EN 3475-605:2010EN 3475-605:2010 (E) 4 1 Scope This standard specifies a method for appraising the behaviour of cable insulation subjected to an electric arc initiated and maintained by a contaminating fluid. This standard shall be used together with EN 3475-100. The pri
17、mary aim of this test is: to produce, in a controlled fashion, continuous failure effects which are representative of those which may occur in service when a typical cable bundle is damaged and subjected to aqueous fluid contamination such that electrical arcing occurs, between cables; and to examin
18、e the aptitude of the insulation to track, to propagate electric arc to the electrical origin. Originally defined for 115 Vac network, this test also proposes conditions for 230 Vac network. Unless otherwise specified in product standard, only 115 Vac conditions shall be satisfied. Six levels of pro
19、spective fault current have been specified for concerned cable sizes (see Clause 7). It is generally agreed that larger sizes need not be assessed since the short-circuit phenomenon becomes dominant at low line impedances. Unless otherwise specified in the technical/product standard sizes 002, 006 a
20、nd 020 cable shall be assessed. 2 Normative references The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) app
21、lies. EN 2350, Aerospace series Circuit breakers Technical specification EN 3197, Aerospace series Installation of aircraft electrical and optical interconnection systems 1)EN 3475-100, Aerospace series Cables, electrical, aircraft use Test methods Part 100: General EN 3475-302, Aerospace series Cab
22、les, electrical, aircraft use Test methods Part 302: Voltage proof test A-A-52083, Tape, lacing and tying, glass 2)3 Specimen requirements Cables to be tested shall be of traceable origin and shall have passed the high voltage dielectric test defined in the product standard. 1)Published as ASD Prest
23、andard at the date of publication of this standard.2)Published by: Department of Defense Industrial Supply Center, ATTN: DISC-BBEE, 700 Robbins Avenue, Philadelphia, PA 19111-5096 USA. BS EN 3475-605:2010EN 3475-605:2010 (E) 5 4 Preparation of specimen 4.1 Cut seven separate lengths of approximately
24、 0,5 m consecutively from one length of cable, and strip one of the ends of insulation to permit electrical connection. Clean each length of cable with a clean cloth moistened with propan-2-ol (isopropyl alcohol) fluid. 4.2 Lay up the seven cables as follows: a) Form the cables in a six around one c
25、onfiguration as shown in Figure 1. b) Ensure that all cables are straight and geometrically parallel, and restrained by ties such that they are in continuous contact at least within the test zone. c) Position the ties at 50 mm spacing toward the end of the specimen as shown in Figure 2. The first ti
26、e shall be at no more than 5 mm behind the dripping point. The tie material shall be PTFE glass lacing tape conforming to A-A-52083, type IV, finish D, size 3. d) Position the ties at 50 mm spacing toward the end of the specimen as shown in Figure 2. The first tie shall be at no more than 5 mm behin
27、d the dripping point. The tie material shall be PTFE glass lacing tape conforming to A-A-52083, type IV, finish D, size 3. Dimensions in millimetres Key 1 Drop needle A1-A2: Phase A B1-B2: Phase B C1-C2: Phase C N: Neutral cable connected to earth Figure 1 Specimen configuration BS EN 3475-605:2010E
28、N 3475-605:2010 (E) 6 Dimensions in millimetres Key 1 Cable tie 2 Drop needle 3 Drops 4 Ends of the seven cables in the same plane Figure 2 Test configuration 5 Apparatus 5.1 Electrical equipment Connect the seven cables of the test sample within a circuit as shown in Figure 3. This circuit shall ha
29、ve the following requirements: a) The provision of adjustable levels of prospective fault currents for the six A, B and C cables. b) A three phase 115/200 V 400 Hz (115 Vac network) or 230/400 V 400 Hz (230 Vac network) star (Y) connected supply shall be derived from a dedicated rotary machine capab
30、le of sustaining the maximum prospective fault current given in Table 1 for at least sufficient time for circuit protection to operate. In any case the generator shall have a sufficient rating to provide these prospective fault currents. c) 115 Vac or 230 Vac circuit breakers shall be single pole un
31、its rated at the values specified in Table 2. They shall have trip characteristics in accordance with EN 2350 or as required in the product specification. NOTE 1 Reference of circuit breakers used should be recorded. NOTE 2 In particular case, others ratings of thermal breaker protection could be em
32、ployed in accordance with aircraft manufacturer rules. d) The electrical power source shall be appropriately protected and it shall be established that no combination of test circuit events would activate this protection. BS EN 3475-605:2010EN 3475-605:2010 (E) 7 e) The ballast Rb resistors shall be
33、 non-inductive and of appropriate power rating. Care shall be taken to position all laboratory wiring such that inductive effects are reduced to a practical minimum. Supply cables shall be as short as possible. The ballast resistor Rb is in order to prevent over voltage (115 115 W per phase for 115
34、Vac network or 230 230 W per phase for 230 Vac network) during the arc extinction phases (opening of an inductive circuit). f) A rheostat, Rf, limiting maximum short-circuit current per phase by simulating a line length. g) Appropriate instrumentation, recording and switching control shall be instal
35、led in accordance with good laboratory practice. Key Rf Rheostat Rb Ballast resistor 1 Supply protection 2 Test bundle Figure 3 Test schematic circuit 5.2 Test equipment Construct an apparatus as shown diagrammatically in Figure 2, which includes the following minimum provisions: a) Electrical termi
36、nations to provide a ready means of connecting test specimens into the circuit as shown in Figure 3. b) A transparent enclosure to protect personnel from ejected molten metal and short wavelength ultra violet light. c) An electrolyte delivery system which provides a constant rate of (100 10) mg/min
37、and dispenses drops from an 18 gauge needle, cut of square at the outlet. BS EN 3475-605:2010EN 3475-605:2010 (E) 8 NOTE The needle wall thickness should be selected such that the specified flow rate is delivered at approximately six drops per minute. 5.3 Test protocol 5.3.1 The procedure embraces c
38、opper cable sizes 001 to 051 (26 to 10) or copper clad aluminium cable sizes 002 to 090 (24 to 8), and for each cable size six values of prospective fault current have been defined. Performance of a cable size at a given fault intensity shall be determined by testing three samples. Thus 18 samples a
39、re required for every cable size. 5.3.2 For the purposes of cable qualification at least sizes 002, 006 and 020 shall be tested. Additional testing of other sizes may be deemed necessary in particular cases and values of prospective fault currents, the ratings of thermal breaker protection which are
40、 typical of aircraft use have been included in this specification. 5.3.3 It is emphasized that electrical arcing tests are essentially destructive and can be hazardous to personnel. Therefore tests shall be undertaken with all observers shielded from direct physical and visual exposure as noted in 5
41、.2, b). The use of video recording for all tests is required. 5.4 Test rig set-up 5.4.1 Install the rating of circuit breaker appropriate to the cable type and size to be tested (Table 2). 5.4.2 Heavy duty electrical shorting connections shall be fitted in substitution of a test sample to enable pro
42、spective fault currents to be set by adjustment of resistances Rf. Because these currents would trip the thermal breakers very rapidly these shall be shunted to permit the pulsing of current until the desired value is obtained. Re-instate the thermal protection. 5.4.3 Prepare an electrolyte solution
43、 made by dissolving (3 0,5) % by weight of sodium chloride in distilled water. 5.4.4 Support the specimen in free air inclined at an angle of 10 to the horizontal with the electrical input connections at the higher end. 5.4.5 Position the delivery system so that the electrolyte contacts the loom fro
44、m a height of (10 2) mm above the uppermost cables in the loom at a point which shall position the droplets into the upper cut or no more than 2 mm towards the higher end of the specimen. Ensure that the drops strike the cables at the top centre of the circumference such that they fall into the crev
45、ice between cables A1 and B1. 6 Method 6.1 Test procedure 6.1.1 Install a test specimen with electrical connections as shown in Figure 1 and with Rf set, as 5.4.2 above, to give the required current from Table 1. 6.1.2 Apply electrical power to the specimen and start the flow of electrolyte at a rat
46、e of (100 10) mg/min. Particular care shall be taken to ensure that the electrolyte flows between the damage sites as evidenced by steaming of the electrolyte and the development of scintillation. Shall this not occur, and failure of the cable to wet be determined, then the alternative surfactant de
47、scribed in 5.4.3 may be used. 6.1.3 Run the test continuously for a period of 2 h. If the circuit-breaker(s) of phases A1, A2, B1, B2, C1 and C2 do not trip for a duration of 2 h, switch off the power supply and the electrolyte flow. Stop the test. BS EN 3475-605:2010EN 3475-605:2010 (E) 9 6.1.4 Fol
48、lowing CB(s) tripping adopt the following procedure: a) After not less than 3 min, not more than 10 min, and with all thermal circuit breakers closed, reapply power to the specimen with no further flow of electrolyte. b) Apply power for the time necessary for any fault condition to develop fully but
49、 do not reset the thermal circuit breakers. 6.1.5 Repeat the test to obtain three samples and then reset the circuit for the next highest current overload until all 18 samples have been tested. 6.2 Examination 6.2.1 EN 3197 can be used as a guideline to differentiate short-circuit and arc-tracking effects. Noticeable damages may come from ever: aptitude of the insulation to become an electrically conducting material (arc-tracking phenomenon); propagation of thermal effects due to establ
