BRITISH STANDARD OBSOLESCENT MARCH 1977 BS 2E 21 1957 Incorporating Amendment Nos 1, 2, 3 and 4 Pren type electric cables for aircraft NOTE The current ratings quoted in this British Standard apply on[.]
BS 2E 21:1957 BRITISH STANDARD Incorp orating Am endm ent No s O BS O LE S C E NT MARC H 977 Pren type electric cables for aircraft NO TE The current ratings quoted in this Britis h S tandard ap p ly only when the cab les are us ed in aircraft, and are nominal values Actual ratings ap p rop riate to various conditions of ins tallation in aircraft are given in S ection J of Britis h C ivil Airworthines s Requirements UD C 62 : 62 66 Reprodu ced by I H S u n d er l i cen se wi th BSI - U n trol l ed Copy and , 2, BS E : 95 Fore word This revision of BS E 21 has been prepared to bring the specification up to date in the light of current practice and of experience gained in working to the first issue, published in November 952 The principal changes are: — a) the introduction of Duprensheathround cable; b) the modification of the construction of Septopren, Septoprenmet and Septoprensheath cables to consist of seven cores laid up around a central dummy core, and to avoid confusion with cables in the previous issue of this standard, the addition of the suffix “large” to the names of these cables; c) the introduction of Sextoprensheath and Nonoprensheath cables; d) the deletion of reference to Uniflexpren cable and the introduction of a Uniflexpren cable, coloured black; e) the amendment of the values required for the physical properties of the polychloroprene compound insulation and sheath; f) the introduction of a requirement for the printing of the letters “AL” in addition to the current rating on aluminium cables 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 C o mp liance with a British S tand ard doe s not o f itself co nfer immunity fro m le gal ob ligations S ummary o f p age s This document comprises a front cover, an inside front cover, pages i and ii, pages to 1 and a back cover This standard has been updated (see copyright date) and may have had amendments incorporated This will be indicated in the amendment table on This British Standard, having the inside front cover been approved by the Aircraft Industry Standards Committee, and endorsed by the Chairman of the Engineering Divisional Council, Amendme nts issue d since p ub lication was published under the authority of the General Amd No Date of issue 441 January 962 5947 November Council of the Institution on 23 December 957 © BSI 04- 2000 966 The following BSI references relate to work on this standard: — Committee reference ACE/6 46 968 Draft for comment CW(ACE) 9628 2250 IS B N 80 Reprodu ced by I H S u n d er l i cen se wi th BSI - U n trol l ed Copy November March 977 Comments BS 2E 21:1957 Contents Page Foreword I ns ide front cover S cop e S ection Requirements Materials C onstruction Fas tness of colours of cab les C urrent rating identification I dentification of manufacturer and year of manufacture Packing and lab elling of cab le S ection Tests General Res istance to fluids 10 Ageing in air 11 Low temp erature tes t 12 Flexib ility 13 Voltage tes t 14 C onstruction 15 Voltage test on core 16 I ns ulation res is tance tes t on core 17 S p ark tes t on core 18 Voltage tes t on comp leted cab le 19 C onductor resis tance test on comp leted cab le 20 I dentification, p acking and lab elling 21 Non- inflammab ility tes t 22 Mechanical s trength of conductors 23 Tinning test 24 Physical p rop erties of ins ulation and s heath Ap p endix A Nomenclature 11 Ap p endix B Metal b raiding details 11 Figure Tab le — D etails of unip ren cab les Tab le — D etails of p renal cab les Tab le — D etails of trip ren, quinp ren and sep top renlarge cab les Tab le — D etails of unip renmet cab les Tab le — D etails of trip renmet, quinp renmet and s ep top renmetlarge cab les Tab le — D etails of p rensheath cab les Tab le — C olour scheme for multi- core cab les Tab le — C olours of cellulos e acetate marker thread for the identification of the year of manufacture Tab le — Resis tance to fluids 10 Tab le — E lectrical tests on cores 10 Tab le 1 — Non- inflammab ility tes t 10 Tab le — Tens ile tes ts on conductors 10 Tab le — Phys ical p rop erties of p olychlorop rene comp ound ins ulation and sheath © BS I 4- 00 Reprodu ced by I H S u n d er l i cen se wi th BSI - U n trol l ed Copy 10 i ii Reprodu ced by I H S u n d er l i cen se wi th BSI - U n trol l ed Copy blank BS E : 95 b) Aluminium conductors Aluminium wires shall be S cop e This British Standard specifies the requirements for “Pren” type cables for aircraft wiring of circuits where the potential between conductors, or between a conductor and metal braid or the aircraft structure does not exceed 600 volts (r m s ) in voltage and 600 c/s in frequency; also where any combination of ambient temperature and conductor current for continuous service does not produce a stabilized conductor temperature in excess of 90 °C These cables are suitable for fixed wiring in aircraft when low temperatures (– 75 ° C) are encountered, but are not suitable for severe flexing below – 40 ° C The cables not support combustion but they should not be regarded as complying with the requirements of BS G 00, “General requirements hard drawn and, before stranding, shall comply with the requirements of BS 2791 , “Aluminium conductors in insulated cab les ”, where applicable Aluminium wires taken from the stranded or bunched conductor shall comply with the tensile and wrapping test requirements of Clause 22 of this British Standard c) Glass b raid The free alkali content of the glass shall not exceed per cent The glass shall be of such fineness that the finished cable complies with all the test requirements of this British Standard d) Polychloroprene compound The polychloroprene compound shall be of such a quality that the finished cable complies with all the test requirements of this British Standard for electrical equipment and indicating instruments e) Lacquer The lacquer shall consist of a for aircraft ”, in regard to fire resistance non- inflammable, heat- , oil- , and water- resistant The cables are unsuitable for use without additional compound protection in areas where ester- based fluids are present C onstruction The generic name “Pren” shall be applied only to a) General cables covered by this British Standard and i) Conductor The conductor shall be braided, complying with all requirements of the bunched, stranded or rope stranded, as specified specification It shall consist of tinned annealed copper wires The standard includes the following four ranges of complying with the requirements of Clause cables, the complete nomenclature of which is given or of hard drawn aluminium wires complying in Appendix A: — with the requirements of Clause a) Pren Cable with a copper conductor and an insulation of glass braid and polychloroprene compound, for single core cables: multi- core cables have an overall finish of glass braid and lacquer: the conductor of the Uniflexpren cable is of a braided construction which shall not be on a string centre b) Prenal Similar to the Pren range but with a conductor of aluminium instead of copper c) Prenmet Similar to the Pren range but with the addition of a metal braid d) Prensheath Multi- core Pren cables sheathed with a polychloroprene compound in place of the lacquered glass braid S e ction Require me nts 2 a), b) Joints in the single copper wires shall be brazed or soldered but the complete conductor shall not be j oined In the case of aluminium and braided copper conductors the ends of the wires may be tucked into the conductor The conductor of the Uniflexpren cable shall be of a braided construction which shall not be on a string centre Table and Table state the number and diameter of individual wires and the formation to be used for the complete conductor There shall be no kinks or other irregularities in the conductor ii) Complete cab le The insulation adj acent to the conductor shall consist of a glass braid A polychloroprene compound, the colour of which shall be in accordance with Clause 5, shall be applied over the glass braid to the dimensions given in Table and Table The insulation shall Mate rials be of uniform circular cross- section throughout a) Copper conductors and wires Copper conductors the length of the cable and the conductor shall be and wires shall be in accordance with BS 7, evenly centred in the insulation “Rub b er-insulated cab les and flexib le cords for electric power and lighting”, as far as applicable Wires taken from conductors, but not from braids, shall meet the requirements for maximum tensile strength and minimum elongation at break specified in Clause © BSI 04- 2000 Reprodu ced by I H S u n d er l i cen se wi th BSI - U n trol l ed Copy 22 The insulation shall not be loose, but it shall be possible to strip the complete insulation, leaving the conductor in a condition sufficiently clean to permit satisfactory connection to terminations of this British Standard BS 2E 21:1957 The radial thickness at any point in the wall of The diameter of wire used shall be as stated in the polychloroprene compound shall be not less Table The number of spindles and ends per than the values given in Table and Table spindle shall be such as to ensure that the filling Current ratings shall be identified by the method factor is not less than 70 The lay factor shall not specified in Clause exceed The formulae to be used for the b) Unipren cab les The cables shall consist of single cores complying with the requirements of Clauses a), c), d) and a) The polychloroprene compound insulation shall be coloured and marked as required in Clause Appendix B f) Prensheath cab les The cables shall consist of cores of the multi- pren range and shall be sheathed overall with a polychloroprene compound of the c) Multi-core cab les Multi- core cables shall be coloured as stated in Clause and Table 7: they shall be circular Septoprenlarge cable shall consist of seven cores laid up around a central dummy core The laid- up cores shall be covered with a glass braid coated with a non- inflammable, heat- , oil- , and water- resistant lacquer coloured in accordance with Clause calculation of the above details are given in If fillers are used to thickness specified in Table The sheath shall be coloured as stated in Clause and shall not be loose but it shall be possible to remove it from the cores without damaging them If fillers are used to provide a good shape, they shall be of polychloroprene compound, supported, if desired, by a thin textile thread The overall dimensions of the cable shall comply provide a good shape they shall be of with the values given in Table polychloroprene compound supported, if desired, by Prensheath cables shall be circular, and shall a thin textile thread consist of appropriate cores coloured as specified in It shall be possible to strip the glass braid and Table Sextoprensheath and lacquer from the cores without damage to the latter The overall dimensions of the cables shall comply with the values given in Table d) Prenal cab les The cables shall consist of single cores complying with the requirements of Clauses b), c), d) and Nonoprensheath cable shall consist of two cores twisted together with seven cores around them Fastness of colours of cables All colours shall be fast to light and moisture The a) The polychloroprene compound shall be coloured and marked as specified in Clause Septoprensheathlarge cable shall consist of cores laid up around a central dummy core e) Prenmet cab les The cables shall consist of Pren cables to which has been added a metal braid materials used shall be capable of retaining their colours after storage for long periods in the tropics Current rating identification Single- core cables shall consist of Unipren type The nominal current rating of Unipren cables up to cable to which a metal braid has been applied and including the ampere size shall be indicated Multi- core cable shall be constructed by metal by colouring of the polychloroprene compound as braiding a multi- core Pren cable follows: — Uniflexpren black shall be used to form the overall metal braid The Unipren red braid shall be close fitting, but wherever the cable Unipren blue is cut it shall be possible to slide the metal braid Unipren brown back by hand a distance of in in a length of ft, Unipren yellow Tinned copper wires, as specified in Clause a), one end of the cable being clamped The braid shall subsequently be capable of being returned to within in of its original position Where breaks in the individual wires occur, the ends shall be soldered or tucked out of the braid and there shall be not more than one such break in Unipren cables of ampere size and over shall have the polychloroprene compound coloured blue and the nominal current rating shall be indicated by numerals permanently and legibly printed Preferably, the horizontal axis of the figures should be parallel to the axis of the cable (see Figure ) The any in length of cable printing, which shall be black, shall be repeated at Where renewal of spindles is necessary, the ends intervals of not more than in The height of the shall be tucked out of the braid, and there shall not numerals shall be approximately two- thirds the be more than one spindle renewal in maximum overall diameter of the core for sizes up to any 2- in length of cable and including 00 amperes and the size of numeral There shall be no j oints in the complete braid used for the 00 ampere cable shall be used for all Reprodu ced by I H S u n d er l i cen se wi th BSI - U n trol l ed Copy cables above this size © BSI 04- 2000 BS E : 95 Uniprenal cables shall have the polychloroprene An additional coloured marker thread or threads compound coloured yellow and the nominal current made of cellulose acetate, or other similar material rating shall be indicated by numerals in the same readily soluble in acetone, shall be included for way as for the Uniprenal and larger cables In identification of the year of manufacture of the addition the letters “AL” shall accompany the cable This shall be taken as the year in which the numeral, preferably as a suffix (see Figure ) vulcanizing of the insulation is commenced, and the Multi- pren, multi- prenmet and multi- prensheath colours shall be as stated in Table cables shall have the lacquer or polychloroprene The marker threads shall be placed between the conductor and the glass braid They shall not be laid compound cover coloured as follows: — ampere cables red ampere cables blue ampere cables brown ampere cables yellow ampere cables and over blue within the conductor Packing and lab e lling of cab le Except for Uniflexpren cable, the length of cable, in one piece and on a separate coil, reel or drum shall be 00 yards, or as stated in the contract The colours of the individual cores in multi- core cables shall be in accordance with Table 7, and the blue core in ampere cables and above shall be printed with the current rating as for Unipren For Uniflexpren cable the minimum length of one piece shall be 25 yards and there shall not be more than three lengths on any 00- yard reel cables After testing, the cable shall have the ends sealed to If desired by the cable maker, one bobbin of coloured prevent the ingress of moisture Each length shall cotton or glass thread may be incorporated in the bear a linen label giving the following particulars: — glass braid adj acent to the conductor to assist the a) Name of manufacturer cable maker during the production of cores The b) Nomenclature of cable, e g Unipren colour of this thread when used shall be red for ampere cores, blue for ampere cores, brown c) Size of conductor, e g 9/ 006 for ampere cores and yellow for ampere cores d) British Standard number and year of issue Where the polychloroprene compound is applied in e) Date of manufacture (month and year) more than one layer, the outer layer only need be f) Release reference number coloured g) Actual length in yards Ide ntification of manufacture r and S e ction Te sts year of manufacture The manufacturer shall not mark the cable itself General with his name and address, but a marker thread or Tests shall be made to prove compliance with all threads of cotton or other material insoluble in requirements of this British Standard It is not acetone shall be used, the colours being in intended or recommended that complete tests shall accordance with the current British Standards be made on every cable length supplied Institution register of colours of manufacturers’ identification threads for electric cables and cords, PD 2379 The manufacturer shall, upon request, produce evidence to the satisfaction of the purchaser that cable of the type to be supplied to this British Standard fulfils its requirements The manufacturer shall disclose to the purchaser any proposal to introduce constructions or processes differing from those used for the cable submitted to type tests, and shall obtain the purchaser’s written approval before applying the change to production Figure © BSI 04- 2000 Reprodu ced by I H S u n d er l i cen se wi th BSI - U n trol l ed Copy BS 2E 21:1957 Three kinds of tests are specified, as follows: — a) Typ e tests (Clauses to 24 ) which shall each be Two samples of cable shall be selected from the production batch, one sample being of the smallest made on separate specimens from a sample size produced Specimens from each of these selected by the manufacturer from each of the samples shall each be subj ected to the tests in following groups of cables, a sample being Clauses 21 to 24 Should either of the samples fail regarded as representative of all of the sizes of on any one of the tests, the tests shall be repeated on cables in its group, provided that they are made specimens from four further samples selected at by the same process and with the same materials, random Should any one of these samples fail, the within the group from which it is selected: — batch shall be deemed not to comply with this British Standard Pren cab les: Group For the tests in Clauses Unipren to Group Unipren to 00 Group Unipren 35 to 280 Group Uniflexpren Group Tripren to Group Tripren to 24 Group , 10 , 11 , 12 , 21 and 24 , the metal braid on Prenmet cables shall be removed Type tests only Resistance to fluids The test specimen shall be bent into a single loop, the internal diameter of which is six times the Quinpren and maximum specified diameter of the complete cable Septoprenlarge The specimen shall be immersed in the fluids listed Prenal cab les: in Table and maintained at the stated Group Uniprenal 35 to 00 temperature for not less than 24 hours, with the Group Uniprenal 35 to 200 cable ends out of the liquid At the conclusion of this period the cable shall be Prenmet cab les: removed from the fluid and shall be wound on a Group Uniprenmet to Group Uniprenmet to 50 Group Triprenmet to 24 The specimen shall be kept on the mandrel for one Quinprenmet and minute and then unwound The cable shall show no Group mandrel, the diameter of which is three times the maximum specified diameter of the complete cable signs, to normal vision, of splitting or cracking, and Septoprenmetlarge the change in diameter shall not exceed the value Prensheath cab les: Group given in Table During, and at the conclusion of Duprensheath 6, Duprensheathround and the test, the colour of the cable shall not be appreciably affected Triprensheath Group 10 Ageing in air Quinprensheath to Nonoprensheath b) Production routine tests (Clauses 14 to 20 ) which shall be made on every length of cable c) Production quality tests (Clauses 21 to 24 ) A specimen, at least in long, shall be placed in an air oven, maintained continuously at 00 ± °C for seven days At the conclusion of this ageing period, the sample shall be removed from the oven and kept which shall be made on each batch for fifteen minutes at a temperature of ± °C of 00 000 yards of cable, or at least once during The specimen shall then be wound on a mandrel, the each month’s production, whichever is the less A diameter of which is four times the maximum batch of cable may consist of different sizes and specified dimension of the complete cable After one types but, wherever possible, the sample should minute on the mandrel the specimen shall be be representative of the sizes and types being unwound and it shall show no undue deterioration produced 11 Low temperature test In the following tests the mandrels shall be of metal and shall be allowed to cool to the specified temperature with the cable Reprodu ced by I H S u n d er l i cen se wi th BSI - U n trol l ed Copy © BSI 04- 2000 BS 2E 21:1957 A specimen of the cable, at least in long, shall be stored in air at – 30 ± ° C for a period of six hours, immediately after which it shall be wound on a mandrel, the diameter of which is ten times the maximum specified diameter of the cable The rate of winding shall be approximately one convolution per second After one minute on the mandrel, the cable shall not show, to normal vision, any signs of cracking Multi- core Pren and multi- core Prenmet cables shall be tested at a temperature of – ± ° C NOTE Cables fulfilling the requirements of this test will withstand a temperature of – 75 ° C when installed in aircraft and not subj ect to movement 15 Voltage test on core Except when tested in accordance with Clause 17 , all core shall be immersed in water at room temperature for not less than consecutive hours: at the end of that time whilst so immersed it shall withstand the voltage shown in Table applied between the conductor and the water The voltage shall be applied gradually and maintained continuously for fifteen minutes The regulation of the supply for the voltage test shall be such as to maintain the specified voltage on the cable throughout the test The peak value of the voltage wave shall be within ± per cent of Æ × r m s value and the frequency shall be at any value 12 Flexibility from 25 to 00 c/s A specimen of the complete cable shall be wound on 16 Insulation resistance test on core a mandrel at room temperature, under a tensile load of lb for cables up to and including in in diameter, or lb for cables over in in diameter, into a close helix, the internal diameter of which is three times the maximum specified diameter of the cable The complete test shall comprise five test cycles, each cycle consisting of the winding of the cable on to the mandrel, unwinding and re- winding in the reverse direction, so that the surface of the cable on the inside of the helix during the first winding is on the outside of the helix upon re- winding No part of the cable shall show signs of damage after the test and and the water after one minute’s electrification with the voltage shown in Table 0, shall be not less, when corrected to a temperature of 20 ° C, than the value stated in Table The rate of change of apparent insulation resistance during the one minute’s electrification shall be steady 17 Spark test on core If desired by the manufacturer, a spark test in and insulation resistance test on per cent of all the At the conclusion of each of the tests specified in , 10 , 11 for 000 yards, measured between the conductor accordance with BS on all dry cores and a voltage 13 Voltage test Clauses After the application of the voltage test and whilst the core is still immersed, the insulation resistance 12 , each specimen shall be immersed in water and, whilst so immersed, shall withstand a test voltage of 500 (r m s ), of waveform as specified in Clause 15 , maintained for one minute, applied between the conductor and the core may be made instead of a voltage and insulation resistance test on all core The spark test voltage shall be in accordance with Table 1 and the voltage and insulation resistance tests in accordance with Clauses 15 and 16 water For multi- core cables this test shall be made 18 Voltage test on completed cable on core taken from the complete cable a) Type and production routine tests 14 Construction All cable shall be checked for compliance with the Multi- co re typ es o nly, other than m etal b raided All completed cables shall withstand 000 volts r m s , applied for one minute between each conductor and the remainder connected together The cable shall be tested in a dry state and the voltage supply shall be as specified in Clause 15 requirements of this British Standard relating to b) construction and dimensions metal braiding, shall be tested in accordance with All completed cables shall be examined along the entire length for defective workmanship Metal b raided cab les Clause 18 Multi- core cables, before a) After braiding, all cables, including single- core cables, shall withstand 500 volts r m s , applied for one minute between all the conductors connected together and the metal braid © BSI 04- 2000 Reprodu ced by I H S u n d er l i cen se wi th BSI - U n trol l ed Copy BS E : 95 C onductor resistance test on ii) Aluminium wires shall not break when completed cable subj ected to the following tests: — Wrap the wire round a wire of its own diameter The conductor resistance shall be measured on all to form a close helix of eight turns Unwrap six completed cable and the resistance of a single turns and again closely re- wrap them in the conductor per 000 yards of the finished cable shall same direction as the first wrapping not exceed the value stated in Table and Table (for copper and aluminium respectively) at the b) specified temperature insulation shall be removed carefully from The resistance of multi- core cables in completed form shall not exceed the value specified for the corresponding size of single core cable by more than per cent Conducto rs from Uniflexp ren cab le The a 2- in length of Uniflexpren cable and the conductor as a whole shall be subj ected to a tensile test to determine its breaking load, care being taken to avoid local concentrations of stress at any clamps If this load is 30 lb or less the conductor shall be regarded as satisfactory; if the load is more Identification, packing and than 32 lb the conductor shall be regarded as not labelling meeting the requirements of this specification If the Each coil, reel or drum of completed cable shall load is more than 30 lb but not more than 32 lb the satisfy the requirements of Clauses diameter of the individual wires of the braid forming and for identification of manufacturer and year of the conductor shall be measured: then provided the manufacture and for packing and labelling apparent breaking stress in the conductor (breaking load divided by 48 times the average measured area Type and production quality tests of each of the conductor wires) is not more than 36 000 lb/sq in , the conductor shall be Non-inflammab ility test The number of specimens to be tested is stated in Table 1 All specimens shall be cut consecutively regarded as satisfactory Tinning test from the same coil The tinning of copper conductors shall be tested for Each specimen of cable shall be supported at an compliance with the requirements of BS 7, as far as angle of 45 ° in a draught- free chamber, and the applicable hottest point of a vertical 3- in non- luminous flame ( ) in Bunsen burner) with a blue cone in high shall be arranged to impinge on the central portion of the specimen for the time specified in Table 1 After the source of the flame has been removed, the cable shall meet the following Physical properties of insulation and sheath The insulation and sheath shall be tested for compliance with the properties listed in Table requirements: — a) The cable shall cease to burn within ten seconds b) The total length burned or charred shall not exceed in 2 Mechanical strength of conductors a) Conductors other than from Uniflexp ren cab le i) The tensile strength of each copper or aluminium wire taken from the finished cable, and the minimum elongation of each copper wire taken from the finished cable shall conform to the values given in Table For these tests the gauge length on the test specimen shall be in and the clamps shall be separated at a rate not exceeding five inches per minute The tensile strength shall be calculated on the original crosssectional area of the wire Reprodu ced by I H S u n d er l i cen se wi th BSI - U n trol l ed Copy © BSI 04- 2000 BS 2E 21 :1957 Table — Details of unipren cables Conductor Cable Diameter of conductor Nominal conductor area designation wires a c mils b diameter of permissible finished cable thickness of No of sq in Overall Minimum sq mm Nominal diameter Min compound Max Min of wires in in in in Approximate weight resistance for polychloroprene Max Maximum conductor in 000 yards at 20 ° C in (For reference only) ohms lb/1 00 ft Unipren 000 54 680 347 19 006 033 029 020 05 095 49 66 000 86 1 00 556 19 007 041 037 020 1 0 00 30 95 9 001 50 91 0 966 33 007 052 048 020 1 05 82 1.2 12 001 31 1.17 40 007 061 055 020 30 1 71 1.4 18 003 040 05 70 007 078 072 020 50 35 41 24 005 350 22 110 007 096 090 020 70 55 35 35 008 51 33 73 01 22 1 025 200 85 23 50 01 280 76 20 01 67 55 025 255 235 97 70 020 26 21 3 82 01 21 200 030 31 0 290 30 11 00 033 42 340 21 01 272 254 030 370 350 802 18 35 051 65 770 33 01 345 320 030 445 425 51 26 01 384 359 035 495 470 423 31 01 432 407 035 550 525 325 39 01 490 460 035 61 0 580 252 50 01 548 51 040 680 650 204 62 01 61 585 040 750 720 58 78 004 045 037 020 1 0 00 (7 × 26) 294 (7 × 42) 203 (7 × 29) 40 80 350 063 50 248 (1 × + 18 × 3) 53 04 700 082 70 323 (1 × 7) 68 34 800 06 200 41 (2 × 21 + 17 × 22) 84 66 200 31 230 51 (1 × 27) 09 21 800 70 280 666 (37 × 8) Uniflexpren 000 86 556 1 00 48 34 (1 × braided) a b Calculated on the basis of the formula Calculated on the basis of the formula n Ïd , where d = nominal diameter of each individual wire in inches, and n = number of individual wires in the conductor d n, where d = nominal diameter of each individual wire in mils (1 mil = 001 in ), and n = number of individual wires in the conductor Table — Details of prenal cables Conductor Cable Diameter of conductor Nominal conductor area designation wires a c mils b diameter of finished cable thickness of No of sq in Overall Minimum permissible sq mm Nominal diameter Min compound Max Min of wires in in in in Approximate weight resistance for polychloroprene Max Maximum conductor in in 000 yards at 20 ° C (For reference only) ohms lb/1 00 ft Uniprenal 35 01 400 50 022 28 000 31 41 020 60 50 025 255 235 279 70 020 21 1 99 030 31 0 290 923 020 262 247 030 365 345 281 020 330 31 0 030 435 41 804 12 020 41 398 035 535 51 0 507 17 020 478 453 035 600 570 399 20 020 535 51 0 040 670 640 327 27 020 587 562 040 720 690 255 31 (7 × 0) 70 033 42 000 21 05 (7 × 5) 00 052 35 084 67 200 34 1 06 400 53 68 (7 × 24) 266 (1 × 4) 50 07 36 800 69 342 (1 × 8) 70 31 67 200 84 41 (1 × 22) 200 67 21 800 08 532 (1 × 28) a b See footnote a to Table See footnote b to Table © BSI 04- 2000 Reprodu ced by I H S u n d er l i cen se wi th BSI - U n trol l ed Copy BS 2E 21:1 957 Table — Details of tripren, quinpren and septoprenlarge cables Overall dimensions of finished cable Tripen Current rating Max amperes Quinpren Approximate Approximate weight weight Min in Septoprenlarge Max Approximate weight Min Max Min (For reference (For reference (For reference only) only) only) in lb/1 00 ft in in lb/1 00 ft in in lb/1 00 ft 55 — — — — — — 65 2 32 75 375 32 75 30 4 — — — — — — 12 305 50 — — — — — — 18 350 95 — — — — — — 24 395 335 12 — — — — — — Table — Details of uniprenmet cables Approximate Overall diameter of cable Current Diameter of rating braiding wire amperes Max Min in in weight (For reference only) in lb /1 00 ft 30 1 004 1.5 35 0 004 1.6 40 004 12 70 45 007 18 90 65 007 24 0 85 007 35 40 007 50 95 65 007 11 Table — Details of triprenmet, quinprenmet and septoprenmetlarge cables Overall diameter of finished cable Triprenmet Quinprenmet Septoprenmetlarge Diameter Current rating Approximate Approximate Approximate of braiding weight weight weight wire (For reference in in 85 40 — — — — — — 007 6 95 50 355 305 10 405 355 13 007 305 60 — — — — — — 007 12 335 80 — — — — — — 007 18 380 32 12 — — — — — — 007 24 42 365 15 — — — — — — 007 amperes lb/1 00 ft Reprodu ced by I H S u n d er l i cen se wi th BSI - U n trol l ed Copy Min in in only) lb/1 00 ft Max Min in in (For reference Min only) Max (For reference Max only) lb /1 00 ft in © BSI 04- 000 BS 2E 21 :1957 Table — Details of prensheath cables Minimum radial Cable Overall dimensions of finished cable weight thickness of sheath Max Min in in in D up rens heath D up rens heathround Trip rens heath Quinp rensheath S extop rens heath S ep top rens heathlarge Nonop rens heath a Approximate a × 80 5 × 60 (For reference only) lb /1 00 ft 03 0 03 0 80 60 03 0 95 75 03 0 3 3 03 0 85 65 10 03 0 43 95 12 03 0 495 460 16 3 I n order to ob tain thes e dimens ions , it may b e neces s ary to s elect Unip ren cab les which are b elow the maximum dimens ions for thos e cab les given in Tab le Table — Colour scheme for multi-core cables No of cores Colour of polychloroprene compound Red and b lue Red, b lue and yellow Red, b lue, yellow, green and white Red, b lue, yellow, green, white and b lack Red, b lue, yellow, green, white, b lack and b rown Red, b lue, yellow, green, white, b lack, b rown, orange and violet Table — Colours of cellulose acetate marker thread for the identification of the year of manufacture Date of Colour of Date of Colour of Date of Colour of manufacture marker thread manufacture marker thread manufacture marker thread 95 Brown 60 Yellow/b lack 68 Brown/green 95 Green 61 Yellow/white 69 Brown/b lack 95 Black 62 Yellow/red 70 Brown/white 71 Brown/red 72 Green/b lack 73 Green/white 74 Green/red 95 White 63 Blue/b rown 95 Red 64 Blue/green 95 Yellow/b lue 65 Blue/b lack 95 Yellow/b rown 66 Blue/white 75 Black/white 95 Yellow/green 67 Blue/red 76 Black/red 77 White/red © BS I 4- 00 Reprodu ced by I H S u n d er l i cen se wi th BSI - U n trol l ed Copy BS 2E 21:1 957 Table — Resistance to fluids Fluid represented Test fluid ° Fuel Hydraulic fluid Maximum change in Temperature of test diameter C 70 per cent iso-octane, 30 per cent toluene, by volume 20 ± 80 per cent ethylene glycol monoethyl ether + 20 per cent castor oil by volume 50 ± per cent 15 Table 10 — Electrical tests on cores Insulation resistance Equivalent spark test kilovolts Voltage test volts (r.m.s.) Test voltage Minimum resistance (d.c.) for 000 yards (r.m.s.) megohms 500 500 1.0 up to and including Unipren 135 and Uniprenal 100 above Unipren 135 and Uniprenal 100 Table 1 — Non-inflammability test Cable Time of flame Specimens application tested Unipren to 9, Uniflexpren and Uniprenmet to seconds Unipren 12 to 280, Tripren to 24, Quinpren 6, Septoprenlarge 6, all Prenal, Uniprenmet 12 to 50, Triprenmet to 24, Quinprenmet 6, Septoprenmetlarge 6, and all Prensheath 15 seconds 10 Table — Tensile tests on conductors Material Copper Aluminium Diameter Tensile strength in lb/sq in 0.020 to 0.012 0.011 to 0.003 0.020 Minimum elongation per cent not greater than 43 000 13.5 not greater than 44 000 not less than 20 000 — Table 13 — Physical properties of polychloroprene compound insulation and sheath Tensile strength lb/sq in., minimum Elongation at break, per cent, minimum Tension set on stretching from in to in for hours with hours recovery: per cent, maximum Ageing: after ageing for 120 hours in air at 100 °C tensile strength shall not decrease from the unaged value by more than Elongation at break after ageing, per cent, minimum 10 Reprodu ced by I H S u n d er l i cen se wi th BSI - U n trol l ed Copy 900 400 30 40 per cent 250 © BSI 04-2000 BS 2E 21:1957 Appendix A Nomenclature Prensheath cables (Table 6) Pren cables a) Duprensheath Single core (Table 1) Unipren Unipren 70 00 35 12 50 18 70 24 200 35 230 50 280 Uniflexpren b) Prensheath cables Multi-core (Table 3) Tripren Duprensheathround Triprensheath Quinprensheath Sextoprensheath Septoprensheathlarge Nonoprensheath Appendix B Metal braiding details Formulae to be used in calculating details of overall metal braid filling factor The filling factor 12 Kf is defined as: 18 24 Quinpren Lay factor The lay factor Septoprenlarge KL is defined as: Prenal cables a) where Single core (Table 2) Uniprenal Uniprenal 35 35 50 50 70 70 00 200 D = mean diameter of braid (inches) dw = diameter of braiding wire (inches) L = lay of braiding wire (inches) m = total number of spindles n = total number of ends per spindle Prenmet cables Prenmet cables (Table and Table 5) Uniprenmet Triprenmet 4 6 9 12 12 18 18 24 24 Quinprenmet 35 Septoprenmetlarge 50 © BSI 04- 2000 Reprodu ced by I H S u n d er l i cen se wi th BSI - 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