1、BRITISH STANDARD CONFIRMED MARCH 1992 BS 3036:1958 Incorporating Amendment Nos. 1, 2, 3, 4 and 5 Specification Semi-enclosed Electricfuses Ratings up to 100 amperes and 240 volts to earth UDC 621.316.923BS3036:1958 This British Standard, having been approved by the Electrical Industry Standards Comm
2、ittee and endorsed by the Chairman ofthe Engineering Divisional Council, was published under theauthority of the General Council on 23October1958 BSI 08-1999 The following BSI references relate to the work on this standard: Committee references ELE/78 andELE/78/1 Draft for comment CX (ELE) 2426 ISBN
3、 0 580 02989 1 Co-operating organizations The Electrical Industry Standards Committee, under whose supervision this British Standard was prepared, consists of representatives from the following Government departments and scientific and industrial organizations: Admiralty Air Ministry Associated Offi
4、ces Technical Committee Association of Consulting Engineers (Incorporated)* Association of Supervising Electrical Engineers British Electrical and Allied Industries Research Association* British Electrical and Allied Manufacturers Association* British Electrical Development Association British Railw
5、ays, The British Transport Commission Cable Makers Association Crown Agents for Oversea Governments and Administrations Electric Lamp industry Council Electric Light Fittings Association Electrical Contractors Association (Incorporated)* Electrical Contractors Association of Scotland Electricity Cou
6、ncil, Generating Board and the Area Boards in England and Wales* Engineering Equipment Users Association* Independent Cable Makers Association Institution of Electrical Engineers* Ministry of Labour and National Service (Factory Inspectorate)* Ministry of Power Ministry of Supply Ministry of Works N
7、ational Inspection Council for Electrical Installation Contracting National Physical Laboratory (D.S.I.R.)* Oil Companies Materials Committee* Post Office* Public Transport Association (Incorporated) Radio Industry Council South of Scotland Electricity Board War Office The Government departments and
8、 scientific and industrial organizations marked with an asterisk in the above list were directly represented on the Committee entrusted with the preparation of the standard. Amendments issued since publication Amd. No. Date Comments PD 3614 December 1959 PD 4862 March 1963 PD 5141 February 1964 2463
9、 February 1978 6689 January 1991 Indicated by a sideline in the marginBS3036:1958 BSI 08-1999 i Contents Page Co-operating organizations Inside front cover Foreword iii Section 1. General 1 Scope 1 2 Service conditions 1 3 Definitions 1 Section 2. Requirements 4 Voltage rating 3 5 Sizes 3 6 Temperat
10、ure rise at rated current 3 7 Fusing factors 3 8 Time/current characteristics 3 9 Performance 3 10 Contacts 3 11 Spacing of fixed contacts 3 12 Terminals 3 13 Non-metallic parts 4 14 Shielding and prevention of danger 4 Section 3. Type tests 15 General 4 16 Insulation resistance 4 17 Temperature ris
11、e at rated current 5 18 Time/current characteristics 5 19 Minimum fusing current 5 20 Preparation of fuses for tests for duty 6 21 Testing circuit and earthing 6 22 Tests for duty 6 23 Criteria of failure during tests for duty 7 Section 4. Marking 24 Marking of fuse carriers 7 Appendix A Notes on te
12、rminology 8 Appendix B Measurement of prospective current and cut-off current 9 Appendix C Computation of power factor and time constant from oscillograms 10 Appendix D Deleted 11 Appendix E Measurement of recovery voltage 11 Appendix F Selection of semi-enclosed fuses 11 Appendix G Information to b
13、e included in reports of type tests for breaking-capacity ratings 14 Figure 1 Test circuit for fuses of 240-volt single-phase a.c. rating 15 Figure 2 Alternative test circuit for fuses of 240-volt single-phase a.c. rating 16 Figure 4 Test circuit for fuses of 415-volt three-phase a.c. rating 17 Figu
14、re 5 Typical component parts of a semi-enclosed fuse 18 Figure 7 Typical oscillogram of large prospective current in an a.c. circuit 19 Figure 9 Typical oscillogram of moderate prospective current in an a.c. circuit 19 Figure 10 Measurement of prospective current 20BS3036:1958 ii BSI 08-1999 Page Fi
15、gure 11 Computation of power factor 20 Figure 12 Computation of time constant 21 Figure 13 Typical time/current characteristics of fuses of differentcurrent ratings 21 Figure 14 Typical time/current characteristics of a cartridge fuse and a semi-enclosed fuse of different current ratings 22 Figure 1
16、5 Typical time/current characteristics of a fuse and some other over-current protective device 22 Table 1 Sizes for each category of duty 3 Table 3 Categories of duty for fuses suitable for a.c. circuits 4 Table 4 Cables for test connections to fuses 5 Table 5 Duration of test for minimum fusing cur
17、rent 6 Table 6 Equivalent resistance of lengths of cables of different sizes 12BS3036:1958 BSI 08-1999 iii Foreword Semi-enclosed fuses are used extensively and have given satisfactory service on low- and medium-voltage systems not exceeding 240 volts to earth at points where the breaking-capacity s
18、everity is limited. Such fuses are usually associated either with switches in composite units, or with distribution boards, used on two- or three-pole circuits, the fuses being enclosed within a single case, which is often of metal and is then connected to earth. The semi-enclosed fuses covered by t
19、his standard are suitable for certain applications only. Where fuses are required for points in a system where the prospective short-circuit current exceeds the test values given in the standard, or higher breaking-capacity ratings are required, the appropriate Parts of BS88 “Cartridge fuses for vol
20、tages up to and including1000V a.c. and1500V d.c.”, or with BS1361 “Cartridge fuses for a.c. circuits in domestic and similar premises” should be used. BS88, “Electric fuses for circuits of voltage-ratings up to660volts”, should be used. Fuses within the scope of this standard are not sensitive to n
21、ormal electromagnetic disturbances, and therefore no immunity tests are required. Significant electromagnetic disturbance generated by a fuse is limited to the instant of its operation. Provided that the maximum arc voltages during operation in the type test comply with the requirements of the claus
22、e in this standard specifying maximum arc voltage, the requirements for electromagnetic compatibility are deemed to be satisfied. 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. Compl
23、iance 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, pagesi toiv, pages1to22 and a back cover. This standard has been updated (see copyright date) and may have had amendments incorporat
24、ed. This will be indicated in the amendment table on the inside front cover.iv blankBS3036:1958 BSI 08-1999 1 Section 1. General 1 Scope This standard relates to low-voltage and medium-voltage semi-enclosed fuses, having ratings of240volts maximum to earth, and100amperes or less, intended for any of
25、 the a.c. categories of duty at50Hz included inTable 1 and for use under service conditions not more onerous than those described in Clause2. 2 Service conditions The service conditions for which fuses complying with this standard are suitable are as follows: 1) a) Voltage. Circuits in which the vol
26、tage between lines does not exceed the rated voltage of the fuse,and in which the voltage to earth does not exceed 240 volts. b) Current. Carrying currents from zero current to rated current and breaking currents from the minimum fusing current to the breaking-capacity rating at power factors not mo
27、re severe than those corresponding to the relevant category of duty. c) Ambient temperature. The temperature of the air surrounding the fuse is assumed to have a peak value not exceeding40 C, with an average value not exceeding35 C over twenty-four-hour periods. NOTEUnder normal conditions of servic
28、e, the available cooling air is subjected to natural atmospheric variations of temperature, and the peak temperature occurs only occasionally during the hot season; on those days when it does occur it does not continue for long periods. Meteorological records indicate that temperatures at least10deg
29、C below the peak temperature will occur within the twenty-four-hour period, and that the average temperature over any twenty-four-hour period that includes the peak temperature will be at least5degC below the peak value. d) Altitude. An altitude not exceeding2000metres. e) Atmosphere. An atmosphere
30、not subject to excessive pollution: for example, by pollution from smoke, chemical fumes and salt-laden spray. Such pollution occurs in some industrial areas and in some coastal districts. f) Enclosure. Enclosures similar to those specified for the tests in Section3. NOTEWhere the fuses are mounted
31、in an enclosure it should be established that the clearances between fuses and between each fuse and the wall of the enclosure are not less than those used for the test. 3 Definitions 2) For the purposes of this British Standard the following definitions apply: 3.1 fuse a device for protecting a cir
32、cuit against damage from an excessive current flowing in it by opening the circuit on the melting of a fuse element by such excessive current. The fuse comprises all the parts that form the complete device 3.2 semi-enclosed fuse a fuse in which the fuse element is neither in free air (other than the
33、 air in any external containing case not forming part of the fuse) nor totally enclosed 3.3 fuse element that part of a fuse which is designed to melt and thus open a circuit NOTESemi-enclosed fuses have easily renewable fuse elements, usually of wire. It is normally left to the user to fit the elem
34、ents according to the desired current rating. 3.4 fuse contact a contact suitable for engaging with a fixed contact, and capable of having a fuse element attached to it 3.5 fuse carrier a removable holder, fitted with fuse contacts, for carrying a fuse element NOTEA container for a fuse element may
35、form a fuse carrier or part of a fuse carrier. 3.6 fixed contact a contact, connected to a fixed terminal, suitable for engaging with a fuse contact 3.7 fuse base that part of a fuse which carries the fixed contacts 3.8 minimum fusing current the minimum current at which a fuse element in a fuse wil
36、l melt 3.9 current rating a current, less than the minimum fusing current, stated by the manufacturer to be the current that the fuse will carry continuously without deterioration 1) Where service conditions differ appreciably from those specified, the manufacturer should be consulted in selecting f
37、uses with appropriate ratings. 2) See also further notes on terminology, given inAppendix A.BS3036:1958 2 BSI 08-1999 3.10 size the maximum current rating (expressed in amperes) that a fuse may have when fitted with the appropriate fuse element NOTEA fuse of one size (say 100-ampere) may be fitted w
38、ithafuse element to give it some smaller current rating (say80-ampere). This matter is within the control of the user. Fuse contacts, fuse carriers, fixed contacts and fuse bases are usually described by stating the size of the fuse of which they are a part. 3.11 fusing factor the ratio, greater tha
39、n unity, of the minimum fusing current to the current rating of a fuse, namely: (see AppendixA.2) 3.12 prospective current the current (the r.m.s. value of the alternating component of an alternating current) that would flow, under any conditions, including test or fault conditions, on the making of
40、 the circuit when the circuit is equipped for the insertion of a fuse but the fuse is replaced by a link of negligible impedance. (See AppendixA.3) 3.13 loop that part of a wave which extends from one zero to the next NOTE 1For the purpose of indicating the number of current zeros during arcing time
41、, arcing time may be referred to as including a stated number of loops. NOTE 2As shown inFigure 9andFigure 10, successive loops may have different durations and amplitudes in the region of initiation of current. The larger loops are called major loops and the smaller loops are called minor loops. 3.
42、14 cut-off if the melting of a fuse element prevents the current through the fuse reaching the otherwise attainable maximum (the peak current of the first major loop in an a.c. circuit), the fuse is said to cut off, and the instantaneous maximum current attained is called the cut-off current NOTE 1I
43、n an a.c. circuit the numerical value of the cut-off current may be greater than the numerical value of the prospective current (seeDefinition3.12). NOTE 2A fuse only exhibits cut-off at prospective currents greater than a particular value; the transition point varies with different fuses, and may b
44、e at a prospective current greater than the breaking-capacity rating. 3.15 breaking-capacity rating a prospective current stated by the manufacturer to be the greatest prospective current to which a fuse may be subjected under prescribed conditions of voltage and of power factor 3.16 voltage rating
45、a voltage stated by the manufacturer to be the highest declared voltage, and the highest voltage to earth, if less than240volts, that may be associated with the fuse 3.17 arc voltage the voltage across a fuse during the arcing time NOTE 1The maximum value of the arc voltage may exceed the peak value
46、 of the a.c. recovery voltage. NOTE 2See AppendixA.6. 3.18 pre-arcing time the time between the commencement of a current large enough to cause a break in a fuse element and the instant when the break is initiated 3.19 arcing time the time between the end of the pre-arcing time and the instant when
47、the circuit is broken and the current becomes permanently zero 3.20 total operating time the sum of the pre-arcing time and the arcing time 3.21 recovery voltage of a circuit opened by a fuse or fuses. The r.m.s. value of the normal-frequency a.c. voltage across the terminals of the fuse or fuses af
48、ter the opening of the circuit 3.22 operation the process in a fuse between the beginning of the pre-arcing time and the end of the arcing time. Operation is sometimes called blowing 3.23 discrimination in a series circuit containing two or more current-interrupting devices: the operation, under ove
49、r-current or short-circuit conditions, of only the current-interrupting device appropriate to the portion of the circuit affected. (SeeAppendixF.6) 3.24 duty the satisfactory opening of a fuse, at voltages not higher than the voltage rating of the fuse, of the circuit or circuits protected by it under conditions that produce for the requisite length of time any prospective current greater than its minimum fusing current up to its breaking-capacity rating Fusing factor Minimum fusing current Current rating -
