ASD-STAN PREN 3475-417-2008 Aerospace series Cables electrical aircraft use Test methods Part 417 Fire resistance of cables confined inside a harness (Edition P 1)《航空航天系列 航空器用电缆的试验.pdf

1、ASD STANDARD NORME ASD ASD NORM prEN 3475-417 Edition P 1 January 2008 PUBLISHED BY THE AEROSPACE AND DEFENCE INDUSTRIES ASSOCIATION OF EUROPE - STANDARDIZATION Avenue de Tervuren, 270 - B-1150 Brussels - Tel. + 32 2 775 8126 - Fax. + 32 2 763 3565 - www.asd-stan.orgICS: 49.060 Descriptors: ENGLISH

2、VERSION Aerospace series Cables, electrical, aircraft use Test methods Part 417: Fire resistance of cables confined inside a harness Srie arospatiale Cbles lectriques usage aronautique Mthodes dessais Partie 417 : Tenue au feu des cbles confins dans un harnais Luft- und Raumfahrt Elektrischen Leitun

3、gen fr Luftfahrt Verwendung Prfverfahren Teil 417: Feuerbestndigkeit von Leitungen eingebunden in Bndeln This “Aerospace Series“ Prestandard has been drawn up under the responsibility of ASD-STAN (The AeroSpace and Defence Industries Association of Europe - Standardization). It is published for the

4、needs of the European Aerospace Industry. It has been technically approved by the experts of the concerned Domain following member comments. Subsequent to the publication of this Prestandard, the technical content shall not be changed to an extent that interchangeability is affected, physically or f

5、unctionally, without re-identification of the standard. After examination and review by users and formal agreement of ASD-STAN, it will be submitted as a draft European Standard (prEN) to CEN (European Committee for Standardization) for formal vote and transformation to full European Standard (EN).

6、The CEN national members have then to implement the EN at national level by giving the EN the status of a national standard and by withdrawing any national standards conflicting with the EN. Edition approved for publication 31 January 2008 Comments should be sent within six months after the date of

7、publication to ASD-STAN Electrical Domain Copyright 2008 by ASD-STAN prEN 3475-417:20082 Contents Page Foreword2 1 Scope 3 2 Normative references 3 3 Preparation of specimens.3 4 Apparatus .3 5 Method 4 6 Requirements/Acceptance criteria.5 Annex A (normative) Circuit diagram principle for measuremen

8、t of equipotentials .6 Foreword This standard was reviewed by the Domain Technical Coordinator of ASD-STANs Electrical Domain. After inquiries and votes carried out in accordance with the rules of ASD-STAN defined in ASD-STANs General Process Manual, this standard has received approval for Publicati

9、on. prEN 3475-417:20083 1 Scope This standard specifies a method of testing the fire resistance of fire resistance or fire-proof electrical cables inside a harness. The objective of this test is to qualify these cables when they are confined inside harnesses defined hereafter. Described configuratio

10、ns try to be representative of various cables configuration installed in Aircraft. It shall be used together with EN 3475-100. 2 Normative references The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For u

11、ndated references, the latest edition of the referenced document (including any amendments) applies. ISO 2685, Aircraft Environmental test procedure for airborne equipment Resistance to fire in designated fire zones. EN 2346-002, Aerospace series Cable, electrical, fire resistant Operating temperatu

12、res between 65 C and 260 C Part 002 : General. EN 3475-100, Aerospace series Cables, electrical, aircraft use Test methods Part 100: General. EN 3475-408, Aerospace series Cables, electrical, aircraft use Test methods Part 408: Fire resistance. 3 Preparation of specimens Three specimens per configur

13、ation 0,75 m length shall be tested. 4 Apparatus The test equipment shall be as required in EN 3475-408. Reminder of apparatus requirements: a) Burner: according with ISO 2685 or any other burner or assembly of burners satisfying the following conditions: The minimum width of the burner shall be 50

14、mm Cable length exposed to the flame: 152 mm Diameter or width of the flame at the base of the burner 2 D (D = diameter of the harness under test) Flame temperature: (1 100 80) C. Heat flux density received by the calorimeter: (116 10) kW/m2. b) Test fixture: according with ISO 2685: The frame of th

15、e test fixture shall be vibrated with the following characteristics: Direction perpendicular to the axis of the cable Frequency : (30 5) Hz Minimum acceleration: 4 g. c) Circuit diagram (see Annex A) prEN 3475-417:20084 5 Method 5.1 Preparation of test specimens Unless otherwise specified in the pro

16、duct standard, 3 types of homogeneous harnesses of respective code 002 (AWG 24), 006 (AWG 20) and 020 (AWG 14) shall be tested. The cable used to build the harnesses is a three-core cable EN2346-xxxCyyy (see EN 2346-002). The composition of the harnesses will be 4, 12 and 19 cables connected in seri

17、es as in example for 4 cables. These cables shall be twisted with a lay length of 12 to 16 times the outer diameter of the harness. E1E2 E3 E4 Schema All first conductors of each three-core together in series (1stequipotential E1) All second conductors of each three-core together in series (2ndequip

18、otential E2) All third conductors of each three-core together in series (3rdequipotential E3) An external protection Nickel coated or tin coated copper (85 % minimum coverage) sheath plus a Nomex braid (80 % minimum coverage) (4thequipotential E4). Each sample shall be mounted onto a frame as define

19、d in EN 3475-408. The sample shall be loaded with a force defined in Table 1. Table 1 In daN Gage 24 (002) Gage 20 (006) Gage 14 (020) n1 1,5 4 8 n2 4 8 8 n3 8 8 8 “n“ is the number of three-cores wires EN2346-xxxCyyy. prEN 3475-417:20085 5.2 Procedure The test shall be performed according to EN 347

20、5-408, without fluid immersion. Each sample shall be simultaneously subjected to the combined flame and vibration test during 5 min, then the flame will be removed and vibration still maintained during the following 10 min. The insulation resistance measurements must be performed simultaneously betw

21、een equipotential 1/2 (E1/E2) and equipotential 3/4 (E3/E4). 6 Requirements/Acceptance criteria Check the electrical continuity and insulation resistance of the cables during the test. The minimum insulation resistance shall be 10 000 , unless otherwise specified in the product standard. prEN 3475-4

22、17:20086 A mA 50 mA 0 mA 100 mA62,5 A 0 A 5 A 125 V L N 5 k5 A A 50 mA 0 mA 100 mA 62,5 A 0 A 5 A 125 V L N 5 k5 A mA Annex A (normative) Circuit diagram principle for measurement of equipotentials Figure A.1 Circuit diagram principle for measurement of equipotentials 1 / 2 Figure A.2 Circuit diagram principle for measurement of equipotentials 3 / 4