1、BRITISH STANDARD BS 4678-4: 1982 (Reprinted, incorporating Amendment No. 1) Cable trunking Part 4: Specification for cable trunking made of insulating material UDC 621.315.671:621.315.2:621.315.61:696.6BS4678-4:1982 This British Standard, having been prepared under the directionof the Power Electric
2、alEngineering StandardsCommittee, was published under the authority ofthe Board of BSIand comesintoeffecton 29January1982 BSI 03-1999 The following BSI references relate to the work on this standard: Committee reference PEL/80 Draft for comment 80/20271 DC ISBN 0 580 12510 6 Cooperating organization
3、s The Power Electrical Engineering Standards Committee, under whose direction this British Standard was prepared, consists of representatives from the following: Associated Offices Technical Committee Association of Short Circuit Testing Authorities* British Electrical and Allied Manufacturers Assoc
4、iation (BEAMA) British Railways Board British Steel Corporation Department of Energy (Electricity) Electric Cable Makers Confederation* Electrical Contractors Association* Electrical Contractors Association of Scotland Electricity Supply Industry in England and Wales Energy Industries Council Era Te
5、chnology Ltd. Institute of Purchasing and Supply Institution of Electrical Engineers Ministry of Defence* National Coal Board National Economic Development Office* Trades Union Congress The organizations marked with an asterisk in the above list, together with the following were directly represented
6、 on the Technical Committee entrusted with the preparation of this British Standard: Association of Manufacturers Allied to the Electrical and Electronic Industry (BEAMA) Association of Supervisory and Executive Engineers British Electrical Systems Association (BEAMA) Confederation of British Indust
7、ry Electrical Installation Equipment Manufacturers Association (BEAMA) Light Metal Founders Association National Inspection Council for Electrical Installation Contracting Rotating Electrical Machines Association (BEAMA) South African Bureau of Standards Standards Association of Central Africa Zinc
8、Development Association Amendments issued since publication Amd. No. Date of issue Comments 4948 December 1985 Indicated by a sideline in the marginBS4678-4:1982 BSI 03-1999 i Contents Page Cooperating organizations Inside front cover Foreword ii 1 Scope 1 2 References 1 3 Definitions 1 4 Classifica
9、tion 1 5 Dimensions 2 6 General performance requirements 2 7 General conditions for tests 2 8 Construction 2 9 Mechanical properties 2 10 Resistance to heat 3 11 Resistance to flame propagation 3 12 Insulating characteristics 4 13 Marking 4 Appendix A Trunking marking classification codes 5 Figure 1
10、 Cable supporting test apparatus 5 Figure 2 Cable supporting test sample support 6 Figure 3 Impact test apparatus 7 Figure 4 Figure deleted Figure 5 Ball pressure apparatus 8 Figure 6 Electrical insulating test apparatus 8 Table 1 Temperature classification 2 Table 2 Table deleted Table 3 Impact tes
11、t data 3 Table 4 Flame application time 3 Publications referred to Inside back coverBS4678-4:1982 ii BSI 03-1999 Foreword This Part of this British Standard has been prepared under the direction of the Power Electrical Engineering Standards Committee. It specifies requirements for cable trunking mad
12、e of insulating material. Other Parts of this standard are as follows. Part 1: Steel surface trunking; Part 2: Steel underfloor (duct) trunking; Part 3: Steel lighting trunking (in course of preparation). The definitions of “basic insulation” and “supplementary insulation” given in3.5 and3.6 are ide
13、ntical with those given in BS2754, as amended by Amendment No.1, in accordance with the strong recommendation of that standard. The fire tests specified in clauses10 and11 are based on tests specified in BS6099. An additional clause dealing with “external influences”, e.g.the presence of water, oil,
14、 building materials or corrosive or polluting substances, is currently under consideration and is expected to be added by the issue of an amendment in due course. A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards are responsible for
15、 their correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. Summary of pages This document comprises a front cover, an inside front cover, pages i and ii, pages1 to 8, an inside back cover and a back cover. This standard has been updated
16、(see copyright date) and may have had amendments incorporated. This will be indicated in the amendment table on theinside front cover.BS4678-4:1982 BSI 03-1999 1 1 Scope This Part of this British Standard specifies dimensions and performance requirements for non-flame propagating cable trunking made
17、 of insulating material. It also specifies a system of classification for cable trunking according to its material and properties. 2 References The titles of the standards publications referred to in this standard are listed on the inside back cover. 3 Definitions For the purposes of this Part of th
18、is British Standard the following definitions apply. 3.1 cable trunking a system of enclosures for the protection of conductors or cables, assembled together by means of couplers and allowing cables or conductors to be laid in 3.2 coupler a device for joining together lengths of cable trunking 3.3 i
19、nsulating trunking a trunking that consists of insulating material and that has no conductive components 3.4 non-flame propagating trunking a trunking that is liable to ignite as a result of applied flame, but in which the flame does not propagate and is extinguished within a limited time after the
20、applied flame is removed 3.5 basic insulation insulation applied to live parts to provide basic protection against electric shock NOTEBasic insulation does not necessarily include insulation used exclusively for functional purposes. 3.6 supplementary insulation independent insulation applied in addi
21、tion to basic insulation in order to provide protection against electric shock in the event of failure of basic insulation NOTE to 3.5 and3.6 These definitions of “basic insulation” and “supplementary insulation” are identical with those given in BS2754, as amended by Amendment No. 1 and in IEC Repo
22、rt536, published by the International Electrotechnical Commission (IEC). 4 Classification When compliance with the requirements of clauses8 to12 has been established, cable trunking shall be classified under the following headings, as appropriate. a) According to material. b) According to mechanical
23、 properties: 1) trunking for medium mechanical stresses; 2) trunking for heavy mechanical stresses; c) According to temperature tolerance (seeTable 1). d) According to electrical characteristics: 1) trunking without electrical insulating characteristics; 2) trunking with electrical insulating charac
24、teristics. e) According to resistance against ingress of solid objects: 1) non-protected trunking; 2) trunking protected against solid objects greater than1.0mm (IP4X); 3) dust-protected trunking (IP5X); 4) dust-tight trunking (IP6X). f) According to resistance against ingress of water: 1) non-prote
25、cted trunking; 2) trunking protected against dripping water (IPX2); 3) trunking protected against spraying water (IPX3); 4) trunking protected against splashing water (IPX4); 5) trunking protected against water jets (IPX5). NOTEThe categories of itemse) andf) are taken from BS5490:1977. g) According
26、 to resistance against corrosive or polluting substances: 1) non-protected trunking; 2) trunking with low protection; 3) trunking with medium protection; 4) trunking with high protection. h) According to resistance against flame propagation: 1) non-flame propagating trunking; 2) flame propagating tr
27、unking.BS4678-4:1982 2 BSI 03-1999 Table 1 Temperature classification seeclause4 c) 5 Dimensions The nominal external dimensions (i.e.the width and the height), in millimetres, of rectilinear cable trunking shall be selected from any of the following numbers: 12.5, 16.0, 20.0, 25.0, 32.0, 37.5, 40.0
28、, 50.0, 75.0, 100, 150. 6 General performance requirements Cable trunking shall be so designed and constructed that it ensures reliable mechanical protection to the conductors and/or cables contained in it. Cable trunking shall also provide adequate electrical protection. Cable trunking shall withst
29、and the stresses likely to occur during transport, storage, recommended installation practice and usage. Compliance shall be checked by carrying out all the tests specified in this standard. 7 General conditions for tests 7.1 The tests specified in this standard shall be type tests. 7.2 Type tests s
30、hall not commence until10days after manufacture. 7.3 Samples of cable trunking for the various tests shall be taken from different lengths of cable trunking. Two sets of samples shall be provided. 7.4 Cable trunking shall be deemed to comply with the requirements of this standard if there are no fai
31、lures in any of the tests. If one sample fails in a test, that test and those preceding it, which may have influenced the result of that test, shall be repeated on another set of samples of the number specified. If there are no failures in any of the repeated tests, the cable trunking shall be deeme
32、d to comply with the requirements of this standard. 8 Construction 8.1 The inside and outside surface of the trunking shall be reasonably free from burrs, flash and similar defects. In addition, any edges shall not be liable to damage the conductors or cables. Compliance shall be checked by inspecti
33、on, if necessary after cutting the samples apart. 8.2 If screws or studs are used to secure the cover, the dividers or the coupler, or to provide means of connection for electrical continuity, they shall not be liable to damage the conductors or cables. Screws shall have isometric threads. Where pro
34、vision is made in cable trunking for partitions or dividers for the segregation of circuits, such partitions or dividers shall be adequately secured to the main body of the cable trunking. 9 Mechanical properties 9.1 Requirement. Cable trunking shall have adequate mechanical strength. Compliance sha
35、ll be checked by the tests specified in9.2 and9.3. After the cable supporting test(9.2) the distortion measured shall not exceed5% of the nominal horizontal dimension of the sample, and the cover shall not become detached from the body so as to invalidate the classifications made in accordance with
36、itemse) andf) of clause4. After the impact test(9.3) the samples shall show no signs of disintegration nor shall there be any cracks visible to the naked eye. Any cracks in internal dividers shall be ignored. 9.2 Cable supporting test. Carry out the test on three samples, with the covers secured in
37、position, at a temperature of205C. Securely fix each sample in turn to the test apparatus as shown inFigure 1 andFigure 2. With the sample in position A, subject it to a load of0.13kg per square centimetre of trunking cross-sectional area per metre length. The load shall comprise single-stranded uni
38、nsulated copper cables. After the load has been applied for2h measure the distortion. Then place the sample in position B and again subject it to a load of0.13kg per square centimetre of trunking cross-sectional area per metre length. The load shall again be single-stranded uninsulated copper cables
39、. After the load has been applied for2h measure the length. Table 2 deleted Temperature classification Temperature normally not less than Permanent application temperature range Storage and transport Use and installation C C C 5 25 5 25 5 15 5 to + 60 15 to + 60BS4678-4:1982 BSI 03-1999 3 9.3 Impact
40、 test. Carry out the test on samples each approximately250mm long. Before the test condition the samples at a temperature of602C for240h. Place the test apparatus shown inFigure 3 on a pad of sponge rubber40mm thick, and put this, together with the samples, into a refrigerator, within which the temp
41、erature shall be maintained at 5 1C for trunking classified as 5, and at 251C for trunking classified as 25 (seeTable 1). When the samples have attained the temperature of the air within the refrigerator, or after2h, whichever is the longer period, place each sample in turn in the apparatus with the
42、 cover uppermost so that blows can be applied, firstly to the centre of the cover and secondly to the edge of the cover. Allow the hammer to fall so that it imparts the appropriate impact energy as specified inTable 3. The mass of the hammer shall be as specified inTable 3. Table 3 Impact test data
43、10 Resistance to heat 10.1 Requirement. Cable trunking shall have adequate resistance to heat. Compliance shall be checked by the ball pressure test specified in10.2. The diameter of the impression made by the steel ball shall not exceed2mm. 10.2 Ball pressure test. Prepare three samples by cutting
44、flat portions from the trunking and place them in the horizontal position on a steel support, as shown inFigure 5. Place the support and sample in a heating cabinet at a temperature of602C. As soon as the support and the sample have attained the temperature specified, press a steel ball of5mm diamet
45、er against the surface of the sample with a force of20N. After 1 h, remove the ball and take the sample out of the heating cabinet. When the sample has attained room temperature, measure the diameter of the impression made by the ball. 11 Resistance to flame propagation 11.1 Requirement. Non-flame p
46、ropagating cable trunking with the cover secured in position either shall not ignite or, if ignited, shall not continue to burn when the source of ignition is removed. Compliance shall be checked by the test specified in11.2. If the sample burns during the test, it shall do so slowly and the flame s
47、hall not spread appreciably; any flame shall have died out in less than30s after the removal of the burner. 11.2 Test 11.2.1 General. The test shall be made on three samples, each having a length of600mm. Carry out the test in still air with a Bunsen burner having a nozzle with an internal diameter
48、of9mm1mm. The gas used for the test shall be such that, with the diameter of the flame as specified, the theoretic heat output of the burner is not less than900W. 11.2.2 Procedure. While the burner is still in the vertical position, adjust the flame so that its overall length is100mm and the length
49、of the inner blue cone is50mm. Then support the burner so that its axis is at an angle of45 to the vertical. Hold the sample in such a position that the part above the flame is vertical and that the tip of the inner cone of the flame touches the surface of the sample at a distance of approximately100mm from the lower end, as far as it is practicable. Expose the sample to the flame for the time given inTable 4. Table 4 Flame application time Mechanical classification of trunking seeclause4 b) Impact ener
