1、BRITISH STANDARD BS 842:1965 Incorporating Amendment No. 1 Specification for A.C. voltage-operated earth-leakage circuit breakers UDC 621.316.57.025:621.316.9BS842:1965 This British Standard, having been approved by the ElectricalIndustry StandardsCommittee and endorsed by the Chairman of theEnginee
2、ring Divisional Council, was published under theauthority of the General Council on 15November1965 First publishedJune1939 First revisionNovember1965 BSI 10-1999 The following BSI references relate to the work on this standard: Committee references ELE/10 and ELE/10/18 Draft for comment D64/1587 ISB
3、N 0 580 01330 8 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: Associated Offices Technical Committee
4、Association of Consulting Engineers* Association of Mining Electrical and Mechanical Engineers* Association of Supervising Electrical Engineers* British Electrical and Allied Manufacturers Association* British Railways Board* Cable Makers Association* Crown Agents for Oversea Governments and Adminis
5、trations* Electric Lamp Industry Council Electric Light Fittings Association Electrical Contractors Association (Incorporated)* Electrical Contractors Association of Scotland Electrical Research Association* Electricity Council, The Generating Board and the Area Boards in England and Wales* Electron
6、ic Engineering Association Engineering Equipment Users Association* Independent Cable Makers Association Institution of Electrical Engineers* Ministry of Aviation* Ministry of Defence, Army Department* Ministry of Defence, Navy Department* Ministry of Labour (H.M. Factory Inspectorate)* Ministry of
7、Power* Ministry of Public Building and Works* Municipal Passenger Transport Association (Incorporated) National Inspection Council for Electrical Installation Contracting* National Physical Laboratory (Ministry of Technology) Oil Companies Materials Association* Post Office* Public Transport Associa
8、tion (Incorporated) South of Scotland Electricity Board* The Government departments and scientific and industrial organizations marked with an asterisk in the above list, together with the following, were directly represented on the committee entrusted with the preparation of this British Standard:
9、Association of Short-circuit Testing Authorities Engineer Surveyors Association Lloyds Register of Shipping London Transport Board National Coal Board Amendments issued since publication Amd. No. Date Comments 3259 March 1980 Indicated by a sideline in the marginBS842:1965 BSI 10-1999 i Contents Pag
10、e Co-operating organizations Inside front cover Foreword iii 1 Scope 1 2 Definitions 1 3 Service conditions 1 4 Rating 1 5 Standard arrangement of poles 2 6 Standard voltage ratings 2 7 Standard current ratings 2 8 Frequency 2 9 Marking 2 10 Terminal identification 2 11 Temperature rise 2 12 Earth-l
11、eakage performance 3 13 Test device 3 14 Mains operated trip coils 3 15 Construction 3 16 Operating mechanism 4 17 Connection arrangements 4 18 Test requirements general 4 19 Test certificates 4 20 Type tests 4 21 Temperature rise test 5 22 Operation of the test device 5 23 Endurance test 5 24 Makin
12、g and breaking test 6 25 Through current test 6 26 Resistance to lightning surges 6 27 Routine tests 7 28 Performance test 7 29 Speed of operation 7 30 Performance of test device 7 31 Mains voltage test on tripping device 7 32 High-voltage test 7 Appendix A Service conditions 8 Appendix B Applicatio
13、n of earth-leakage circuit-breakers 8 Appendix C Method of installation 8 Appendix D Function of the test device 9 Appendix E Effect of earth-electrode resistance 10BS842:1965 ii BSI 10-1999 Page Figure 1 Typical test circuit for through current test 11 Figure 2 Circuit for surge test 12 Figure 3 Ty
14、pical voltage-operated earth-leakage circuit-breaker installation.Note insulated lead from “e” to earth electrode 13 Figure 4 Typical voltage distribution in soil surrounding a2m rod electrode 14 Table 1 Voltage ratings 2 Table 2 Current ratings 2 Table 3 Temperature rise 3 Table 4 Operating limits
15、3 Table 5 Terminal capacities 4 Table 6 Endurance test sequence 6 Table 7 Prospective-current values 6BS842:1965 BSI 10-1999 iii Foreword This standard makes reference to the following British Standards: BS 2757, Classification of insulating materials for electrical machinery and apparatus on the ba
16、sis of thermal stability in service. BS 3042, Standard test finger (for checking protection against electric shock). This British Standard for voltage-operated air-break earth-leakage circuit-breakers is an extensive revision of the1939 edition to take account of modern developments in earth-leakage
17、 protection and in the design and production of small circuit-breakers. The voltage-operated type of earth-leakage circuit-breaker is intended to prevent a dangerous potential difference persisting between the general mass of earth and accessible installation metal work. The operation of the device
18、will depend not only upon this potential difference but also upon the earth-leakage circuit-breaker earth-electrode resistance (seeAppendix E). A voltage-operated earth-leakage circuit-breaker may incorporate over-current protection. In such instances it is necessary for the earth-leakage circuit-br
19、eaker to comply with the requirements of this standard and also with the relevant requirements in the appropriate circuit-breaker standard. In this connection, attention is drawn to BS3871-1 1)and BS862 2) . Appendices have been included to assist users in the proper application of voltage-operated
20、earth-leakage circuit-breakers and attention is particularly directed to these. A British Standard for the current-operated type of earth-leakage circuit-breaker is in the course of preparation and this type of circuit-breaker will be more suitable for low-values of earth-loop impedance. NOTEIn plac
21、e of the customary, but incorrect use of the ounce as a unit of force, the unit called ounce-force (abbreviation ozf) has been used in this standard. This is the force which, when acting on a body of mass one ounce, gives it an acceleration equal to that of standard gravity. A British Standard does
22、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 confer immunity from legal obligations. Summary of pages This document comprises a front cover, an inside
23、 front cover, pages i to iv, pages1 to 14 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 the inside front cover. 1) BS3871, “Miniature and moulded-case circuit-breakers”, Part1, “Miniatu
24、re air-break circuit-breakers for a.c. circuits”. 2) BS862, “Air-break circuit-breakers (including totally enclosed and flameproof types) for voltages not exceeding660 volts”.iv blankBS842:1965 BSI 10-1999 1 1 Scope This British Standard specifies requirements for a.c. voltage-operated earth-leakage
25、 circuit-breakers having rated voltages not exceeding500volts and rated currents not exceeding200amperes (seeAppendix B, Appendix C and Appendix E). 2 Definitions For the purposes of this British Standard the following definitions apply: 2.1 voltage-operated earth-leakage circuit-breaker (hereinafte
26、r referred to as circuit-breaker) a device for making and breaking a circuit, and for breaking a circuit automatically when the potential difference between protected metal work of the electrical installation and the general mass of earth exceeds the values specified in Clause12 2.2 number of poles
27、the number of main conducting paths which the circuit-breaker is required to open or close simultaneously 2.3 switched neutral contacts not intended to make or break current and arranged to close before and open after the main contacts for the purpose of isolating the neutral 2.4 prospective current
28、 the current (r.m.s. value of the a.c. component) that would flow in a circuit due to the applied voltage if the circuit-breaker were replaced by a link or links of negligible impedance but without any other circuit change NOTEFor the purpose of this definition the term circuit-breaker includes the
29、short length of cable used to connect the circuit-breaker to the test circuit. 2.5 main contacts the fixed and moving contacts in the main current-carrying circuit 2.6 auxiliary contacts contacts working in conjunction with, and actuated by the circuit-breaker, and serving to control the operation o
30、f auxiliary devices such as trip coils or audible alarms 2.7 leakage trip coil a coil energized directly by voltage between earth and the protected metal work and which directly or indirectly operates the mechanism when this voltage exceeds a specified value 2.8 mains-operated trip coil a coil energ
31、ized by the supply voltage controlled by a leakage trip coil (acting as a relay) to operate the mechanism 2.9 test device a device to enable the protective function of the circuit-breaker to be checked 2.10 rating of a circuit-breaker the values assigned by the manufacturer to define the working con
32、ditions for which the circuit-breaker is made 2.11 applied voltage the r.m.s. value of the voltage applied to a test circuit immediately before the initiation of current 3 Service conditions (See Appendix A) Voltage-operated earth-leakage circuit-breakers shall be suitable for use in the following c
33、onditions of service: 1) An ambient temperature not less than 5 C and not exceeding35 C and having an average value not exceeding30 C measured over a24-hour period. NOTECircuit-breakers complying with this standard may not be suitable for exposure to direct radiation from the sun or other sources of
34、 heat likely to raise temperature above the designated ambient. 2) An earth-loop impedance not exceeding500ohms. 3) An altitude not exceeding2000m above sea level. 4) An atmosphere not subject to conditions giving rise to excessive pollution. 4 Rating Circuit-breakers shall be rated in the following
35、 terms: 1) Number of poles. 2) Voltage. 3) Current. 4) Frequency.BS842:1965 2 BSI 10-1999 5 Standard arrangements of poles The following arrangements of poles shall be standard: 6 Standard voltage ratings The voltage ratings contained in Table 1 shall be standard. Table 1 Voltage ratings 7 Standard
36、current ratings The current ratings contained in Table 2 shall be standard. Table 2 Current ratings 8 Frequency The frequency for the purposes of this standard shall be50cycles per second. NOTECircuit-breakers having voltage, current or frequency ratings other than the values given in Clauses6, 7 an
37、d 8 may be considered as standard provided that they comply in all other respects with the specification. 9 Marking Circuit-breakers shall be marked indelibly with the following particulars: 1) Rated voltage. 2) Rated voltage to earth if other than 240 volts. 3) Rated current. 4) Frequency. 5) “A.C.
38、” or “ ”. 6) Manufacturers name or distinguishing mark. 7) Manufacturers type reference when more than one type is manufactured. 8) Country of manufacture. 9) BS 842. 10) The operation of the test device. (This shall be clearly indicated.) When the marking is on a cover which is not sealed in positi
39、on by the manufacturer the marking of the rated current shall also appear on the main body of the circuit-breaker. 10 Terminal identification The terminals of the circuit-breaker shall be clearly and permanently marked for identification. When in addition, the design of the circuit-breaker is such a
40、s to make it necessary to distinguish between the line and load terminals, the former shall be indicated by arrows pointing towards the circuit-breaker and the latter by arrows pointing away from the circuit-breaker. A diagram showing the correct method of connecting the circuit-breaker shall be for
41、med on, or secured to, each circuit-breaker. NOTEIt is not intended that this diagram should take the form of an internal wiring diagram. It may be formed on the inside of a cover removable for installation purposes. The following terminal markings shall be used: 11 Temperature rise The temperature
42、rise at specified locations in a circuit-breaker tested in accordance with Clause21 shall not exceed the values given below: Single pole and switched neutral Double pole For single phase supply Triple pole Triple pole and switched neutral Four pole For three phase supply Standard voltage rating Volt
43、age to earth 240 415 240 240 Amperes 15 30 60 100 200 Neutral Frame Earth N f or F or frame e or E or earth NOTEFor clarity lower case letters f and e are desirable. 1) Terminals of circuit-breakers fitted with copper contacts: 35degC 2) Terminals of circuit-breakers fitted with contacts having adeq
44、uate and durable facings of silver or similar materials not subject to progressive deterioration: 50 degC 3) Handles, operating devices and parts of enclosures likely to be handled when operating the circuit-breaker: 35 degC 4) Insulating material not likely to be handled in service, including that
45、of the leakage trip coil: as given in Table 3 BS842:1965 BSI 10-1999 3 Table 3 Temperature rise NOTEDetails of insulating materials covered by the classes specified inTable 3 are contained in BS2757, “Classification of insulating materials for electrical machinery and apparatus on the basis of therm
46、al stability in service”. 12 Earth-leakage performance Circuit-breakers shall operate within the limits specified inTable 4 when tested in accordance with Clause28. Table 4 Operating limits 13 Test device Circuit-breakers shall be provided with a test device which shall first open the connection bet
47、ween one side of the leakage trip coil and the frame terminal and then connect this side of the coil through a current limiting resistor to one of the line conductors. The arrangement shall be such that the opening of the circuit-breaker shall automatically isolate the leakage trip coil from the inc
48、oming supply. The connection between the leakage trip coil and the frame terminal shall automatically be restored when the operating means of the test device is released. The test device shall ensure a reliable connection between the leakage trip coil and the frame terminal, and the contacts for thi
49、s purpose shall be of silver or other metal not subject to progressive oxidation likely to cause an increase in contact resistance. The closing force at each pair of contacts shall be not less than1.1N. If ferrous springs are used they shall be of non-rusting steel or shall be coated with corrosion resistant material. Any helical spring associated with the test device shall be in compression, and shall be so secured that in the event of breakage the separated parts shall not become detached and liable to make a
