1、BRITISH STANDARD BS 6946:1988 Incorporating Amendment No. 1 Specification for Metal channel cable support systems for electrical installations UDC621.316.17:621.315.2:62-423.5:62-216.74:669.1:669.018:001.4BS6946:1988 This British Standard, having been prepared under thedirectionof the Power Electric
2、al Engineering StandardsCommittee, was published under the authority ofthe Board of BSI and comes into effect on 30 September1988 BSI 03-1999 The following BSI references relate to the work on this standard: Committee reference PEL/80 Draft for comment 85/25689 DC ISBN 0 580 16704 6 Committees respo
3、nsible for this British Standard The preparation of this British Standard was entrusted by the Power Electrical Engineering Standards Committee (PEL/-) to Technical Committee PEL/80, upon which the following bodies were represented: ASTA Certification Services Association of Manufacturers Allied to
4、the Electrical and Electronic Industry (BEAMA Ltd.) Association of Supervisory and Executive Engineers British Electrical Systems Association (BEAMA Ltd.) Chartered Institution of Building Services Engineers Confederation of British Industry Electrical Installation Equipment Manufacturers Associatio
5、n (BEAMA Ltd.) Electricity Supply Industry in England and Wales Gland Manufacturers Technical Committee Light Metal Founders Association National Inspection Council for Electrical Installation Contracting Rotating Electrical Machines Association (BEAMA Ltd.) Zinc Development Association Amendments i
6、ssued since publication Amd. No. Date of issue Comments 6455 December 1990 Indicated by a sideline in the marginBS6946:1988 BSI 03-1999 i Contents Page Committees responsible Inside front cover Foreword ii 0 Introduction 1 1 Scope 1 2 Definitions 1 3 Design data and calculation of safe working loads
7、 1 4 Construction 2 5 Process of manufacture and protective coating 2 6 Dimensions 2 7 Provision of test samples 4 8 Requirements for safe working loads 4 9 Marking 5 Standard sheet 1 Sizes of channel 7 Figure 1 Examples of multiple configurations 3 Figure 2 Examples of ribbed channel sections 4 Fig
8、ure 3 Measurement of twist 4 Figure 4 Measurement of bowing 5 Figure 5 Slip test 5 Figure 6 Pull-out test 6 Publications referred to Inside back coverBS6946:1988 ii BSI 03-1999 Foreword This British Standard has been prepared under the direction of the Power Electrical Engineering Standards Committe
9、e. It is based on a proposal by the British Electrical Systems Association. 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 of itself confe
10、r immunity from legal obligations. Summary of pages This document comprises a front cover, an inside front cover, pagesi andii, pages1 to8, an inside back cover and a back cover. This standard has been updated (see copyright date) and may have had amendments incorporated. This will be indicated in t
11、he amendment table on theinside front cover.BS6946:1988 BSI 03-1999 1 0 Introduction The metal channels, brackets and other metal components of the system covered by this standard are used to make load-bearing frameworks. The assessment of load-bearing capabilities involves principles of analysis co
12、vered by BS5950-5, as well as certain other considerations outlined in this standard. The designer of an installation needs to know the properties of sections and strength of materials of the components used in manufacture. He also needs data on the performance characteristics of some components. Al
13、l these data should be readily available from the supplier. 1 Scope This British Standard specifies requirements and type tests for channels, brackets and other metal components used in metal channel systems intended for the mechanical support of cables, cable tray, cable ladder and other equipment
14、in an electrical installation. NOTEThe titles of the publications referred to in this standard are listed on the inside back cover. 2 Definitions For the purposes of this British Standard the following definitions apply. 2.1 channel a formed component of regular cross section, thelongitudinal edges
15、of which are turned inwardsthrough180 to form a “U” shape (seestandard sheet1) 2.2 brackets devices designed to provide mechanical strength to the joints when used to connect channel together to form framework 2.3 channel nut an internally threaded device designed to fit inside the channel at any po
16、int along its length, providing a means of attachment 2.4 channel tee bolt an externally threaded device designed to fit inside the channel at any point along its length, providing a means of attachment 2.5 axis X-X the axis that passes through the centroid of the section and is parallel to the open
17、 face of the channel (see standard sheet1) 2.6 axis Y-Y the axis that passes through the centroid of the section and is perpendicular to the axis X-X (seestandard sheet1) 2.7 multiple configuration an arrangement of single channels which are joined down their length (see Figure 1) 2.8 stainless stee
18、l a steel having increased and inbuilt corrosion resistance in the uncoated state due to the properties imparted to the steel during manufacture by the addition of between10% and35% chromium 2.9 plain steel a steel of the non-stainless type which has not been given a separately applied protective co
19、ating against corrosion 2.10 special finish any finish except hot-dip or other zinc coating 3 Design data and calculation of safe working loads 3.1 General The component data listed in3.2 to3.6 shall be provided by the manufacturer. 3.2 Channel NOTE 1The values will be either the nominal manufacturi
20、ng dimensions or calculated from them. NOTE 2Where the section has holes along its length this should be taken into account. a) Mass per unit length of section (inkg/m). b) Overall height and width of section (inmm). c) Thickness of material (inmm). d) Area of section (inmm 2 ). e) Size and location
21、 of any holes (inmm). f) Position of centroid of section (inmm). g) Second moment of area of section about X-X and Y-Y axes (inmm 4 ). h) Minimum yield stress of the material (inN/mm 2 ) (see BS18). i) Minimum ultimate tensile strength (inN/mm 2 ).BS6946:1988 2 BSI 03-1999 3.3 Beam and column load d
22、ata Beam and column load data which shall be determined in accordance with BS5950-5. 3.4 Brackets a) Nominal thickness of material (inmm). b) Minimum yield stress of the material (inN/mm 2 ) (see BS18). c) Minimum ultimate tensile strength (inN/mm 2 ). d) Size and location of any holes (inmm). e) No
23、minal dimensions (inmm and degrees). f) Mass (inkg). 3.5 Channel tee bolts a) Size and grade of channel tee bolt to BS6105 or BS4190. b) Thread details. 3.6 Safe working loads a) Safe working slip load (inN) (see8.1). b) Size and grade of channel nut and set screw. c) Tightening torque (inNm). d) Fi
24、nishes of all items. e) Force to produce1mm movement (inN). f) Recommended safe working pull-out load (inN) (see8.2). 4 Construction Multiple configurations shall be produced by welding in accordance with BS5950-5. NOTESee Figure 1 for examples of multiple configurations. Screws and hexagon nuts sha
25、ll either have a washer face or shall be used in conjunction with washers. 5 Process of manufacture and protective coating 5.1 Channels and brackets Channels shall be manufactured from steel complying with BS1449 or BS2989. When tested in accordance with BS18 steel for the formation of channels shal
26、l have a minimum yield strength of250N/mm 2 . Brackets shall be manufactured from steel complying with BS970, BS1449 or BS4360. When tested in accordance with BS18 steel for the formation of brackets shall have a minimum yield strength of170N/mm 2 . The finish for channels and brackets shall be eith
27、er a zinc coating or a special finish. NOTE 1Zinc coating is the preferred finish. Zinc coating shall be applied either after manufacture or components shall be manufactured from steel that has been zinc coated. If zinc coating is applied to channels after manufacture it shall be hot-dip zinc coated
28、 in accordance with BS729. If zinc coating is applied to brackets after manufacture it shall comply with BS729 or BS1706. Material that has been zinc coated and is used for the manufacture of components in accordance with this standard shall comply with BS2989. In the case of hot-dip zinc coated cha
29、nnel, edges exposed by shearing, cutting, etc.shall be protected by the application of a zinc-rich paint complying with BS4652. NOTE 2In the case of pre-zinc coated channel, edges exposed by shearing, sawing, etc., are permitted. However where the integrity of the corrosion protection is impaired by
30、 welding it is permissible to apply zinc-rich paint complying with BS4652 to the affected area. 5.2 Bolts, hexagon nuts, screws and washers Bolts, hexagon nuts, screws and washers shall be fabricated from steel complying with BS3692, BS970, grade A4 of BS6105 or BS4190. They shall have a protective
31、coating complying with BS1706 or the appropriate Part of BS3382. 6 Dimensions NOTE 1The preferred lengths of channel are3m mm and6mmm. NOTE 2Tighter tolerances than those specified in6.1 to6.5 and note1 may be agreed between the purchaser and the manufacturer. 6.1 Thickness of channel Channel shall
32、be either1.5mm or2.5mm in thickness. The thickness shall be measured after removal of any hot-dip zinc coated or special finishing and shall comply with the appropriate material tolerances of BS1449-1 or BS2989. Tolerances for stainless steel shall comply with BS1449-2. 6.2 Sectional dimensions Chan
33、nel sections shall have the dimensions and tolerances shown in either (a) or (b) of standard sheet1, when measured not less than150mm from the end of the length. NOTEIn the case of thin gauge channels (1.5mm thick), ribs are permissible (see Figure 2 for examples). Squareness and deviation of angle
34、shall be 0.5 between adjacent planes when measured not less than150mm from the end of the length. Channel ends shall be not more than0.5 from square. + 6 0 + 6 0 BS6946:1988 BSI 03-1999 3 NOTEThese are typical arrangements showing the use of channel sections in combination. All dimensions are in mil
35、limetres. Figure 1 Examples of multiple configurationsBS6946:1988 4 BSI 03-1999 6.3 Twist Twist shall be not greater than2.5 per metre when measured by clamping one end of the channel to a flat surface and measuring the angle between the flat surface and the same side of the channel at the opposite
36、end of the length (see Figure 3). 6.4 Bowing Bowing in either the X-X or Y-Y axis shall be not more than5mm for channel3m in length or10mm for channel6m in length, when measured at the centre of the length (see Figure 4). 6.5 Brackets Where brackets have stated angles, the tolerances on these angles
37、 shall be 1. 7 Provision of test samples 7.1 Tests according to this standard shall be type tests. 7.2 Two sets of three samples each shall be provided. The tests shall be carried out on one set of three samples. 7.3 If one sample fails out of the first set of samples the test shall be repeated on t
38、he other set of three samples. All three test samples shall satisfy the requirements of clause8. 8 Requirements for safe working loads 8.1 Safe working slip load 8.1.1 Requirement. When tested in accordance with8.1.2, the force required to give continuous slip shall be not less than three times the
39、safe working slip load given by the manufacturer see3.6 a). 8.1.2 Slip test. Secure a hot-dip zinc coated steel plate having dimensions of40mm 40mm 6mm centrally to an open face of a channel 300mm long, complying with this standard, using a standard channel tee bolt or channel nut, with appropriate
40、nut or set screw, and tighten to a torque stated by the manufacturer see3.6 c). Apply a slowly increasing force to the steel plate as shown in Figure 5. Note the force to give1mm slip. Note the force to give continuous slip. NOTEIf fixings are used at or close to the end of a channel, care should be
41、 taken to ensure that the nut correctly engages with the channel. Figure 2 Examples of ribbed channel sections Figure 3 Measurement of twist + 6 0 BS6946:1988 BSI 03-1999 5 8.2 Safe working pull-out load 8.2.1 Requirement. When tested in accordance with8.2.2, the ultimate failure force shall be a mi
42、nimum of three times the safe working pull-out load given by the manufacturer see3.6 f). 8.2.2 Pull-out test. Secure a length of channel300mm long to a rigid structure giving a free length of channel of1005mm between supports. Position a steel plate having dimensions of40mm 40mm 6mm centrally betwee
43、n the supports and secure to the open face of the channel using a standard channel tee bolt, or channel nut, with appropriate nut or threaded rod, and tighten to a torque stated by the manufacturer see3.6 c). Apply a slowly increasing force to the channel tee bolt or threaded rod, as shown in Figure
44、 6. Record the force at1mm movement and also the force at ultimate failure. 9 Marking 9.1 Channels Channels shall be marked with the following: a) the manufacturers or responsible vendors name, trade mark, or other identifying symbol; and b) the number and date of this British Standard, i.e.BS6946:1
45、988 1) . Marking of the channels shall be repeated at regular intervals of not greater than3m. NOTEMarking should preferably be carried out at intervals of1m. 9.2 Brackets and other components The information given in9.1 shall be marked on each bracket or shall be marked on a label attached to each
46、carton or box in which brackets are supplied. For other components, the information given in9.1 shall be marked on a label attached to each carton or box in which components are supplied. 9.3 Method of marking Marking shall be applied either by stamping, printing, adhesive labels or water slide tran
47、sfers. In the case of printing, marking shall still be legible after being rubbed by hand for15s with a piece of cloth soaked with water and again for15s with a piece of cloth soaked with petroleum spirit. NOTEPetroleum spirit is defined as the aliphatic solvent hexane with a content of aromatics of
48、 maximum0.1% volume, a kauri-butanol value of29, initial boiling point65C, dry point69C and density680kg/m 3 . Figure 4 Measurement of bowing Figure 5 Slip test + 6 0 1) Marking BS6946:1988 on or in relation to a product represents a manufacturers declaration of conformity, i.e.a claim by or on beha
49、lf of the manufacturer that the product meets the requirements of the standard. The accuracy of the claim is therefore solely the responsibility of the person making the claim. Such a declaration is not to be confused with third party certification of conformity, which may also be desirable.BS6946:1988 6 BSI 03-1999 Figure 6 Pull-out testBS6946:1988 BSI 03-1999 7 Standard Sheet1 Sizes of channel NOTEThe dimensions shown in (a) and (b) apply to channels either before application or after removal of any protective co
