1、 IEC 60364-4-43Edition 3.0 2008-08INTERNATIONAL STANDARD NORME INTERNATIONALELow-voltage electrical installations Part 4-43: Protection for safety Protection against overcurrent Installations lectriques basse tension Partie 4-43: Protection pour assurer la scurit Protection contre les surintensits I
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16、blication ou si vous avez des questions, visitez le FAQ du Service clients ou contactez-nous: Email: csciec.ch Tl.: +41 22 919 02 11 Fax: +41 22 919 03 00 IEC 60364-4-43Edition 3.0 2008-08INTERNATIONAL STANDARD NORME INTERNATIONALELow-voltage electrical installations Part 4-43: Protection for safety
17、 Protection against overcurrent Installations lectriques basse tension Partie 4-43: Protection pour assurer la scurit Protection contre les surintensits INTERNATIONAL ELECTROTECHNICAL COMMISSION COMMISSION ELECTROTECHNIQUE INTERNATIONALE VICS 29.120.50; 91.140.50 PRICE CODECODE PRIXISBN 2-8318-9922-
18、2GROUP SAFETY PUBLICATION PUBLICATION GROUPE DE SCURIT Registered trademark of the International Electrotechnical Commission Marque dpose de la Commission Electrotechnique Internationale 2 60364-4-43 IEC:2008 CONTENTS FOREWORD.4 43 Protection against overcurrent .6 430.1 Scope.6 430.2 Normative refe
19、rences .6 430.3 General requirements .7 431 Requirements according to the nature of the circuits7 431.1 Protection of line conductors 7 431.2 Protection of the neutral conductor .7 431.3 Disconnection and reconnection of the neutral conductor in multi-phase systems 8 432 Nature of protective devices
20、 8 432.1 Devices providing protection against both overload current and short-circuit current8 432.2 Devices ensuring protection against overload current only9 432.3 Devices ensuring protection against short-circuit current only.9 432.4 Characteristics of protective devices.9 433 Protection against
21、overload current .9 433.1 Coordination between conductors and overload protective devices.9 433.2 Position of devices for overload protection10 433.3 Omission of devices for protection against overload .10 433.4 Overload protection of conductors in parallel 11 434 Protection against short-circuit cu
22、rrents.12 434.1 Determination of prospective short-circuit currents .12 434.2 Position of devices for short-circuit protection.12 434.3 Omission of devices for protection against short-circuit 12 434.4 Short-circuit protection of conductors in parallel .13 434.5 Characteristics of short-circuit prot
23、ective devices .13 435 Coordination of overload and short-circuit protection .15 435.1 Protection afforded by one device.15 435.2 Protection afforded by separate devices .15 436 Limitation of overcurrent by characteristics of supply .15 Annex A (informative) Protection of conductors in parallel agai
24、nst overcurrent.16 Annex B (informative) Conditions 1 and 2 of 433.1.21 Annex C (informative) Position or omission of devices for overload protection .22 Annex D (informative) Position or omission of devices for short-circuit protection 25 Annex E (informative) List of notes concerning certain count
25、ries28 Bibliography30 Figure A.1 Circuit in which an overload protective device is provided for each of the m conductors in parallel18 Figure A.2 Circuit in which a single overload protective device is provided for the m conductors in parallel18 60364-4-43 IEC:2008 3 Figure A.3 Current flow at the b
26、eginning of the fault19 Figure A.4 Current flow after operation of the protective device cs.19 Figure A.5 Illustration of linked protective device .20 Figure B.1 Illustration of conditions 1 and 2 of 433.121 Figure C.1 Overload protective device (P2) NOT at the origin of branch circuit (B) (refer to
27、 433.2.2a)22 Figure C.2 Overload protective device (P2) installed within 3 m of the origin of the branch circuit (B) (refer to 433.2.2b) 23 Figure C.3 Illustration of cases where overload protection may be omitted (refer to 433.3.1a), b) and d).23 Figure C.4 Illustration of cases where overload prot
28、ection may be omitted in an IT system24 Figure D.1 Limited change of position of short-circuit protective device (P2) on a branch circuit (refer to 434.2.1).25 Figure D.2 Short-circuit protective device P2installed at a point on the supply side of the origin of a branch circuit (refer to 434.2.2) 26
29、 Figure D.3 Situation where the short-circuit protective device may be omitted for some applications (refer to 434.3).27 Table 43A Values of k for conductors.14 4 60364-4-43 IEC:2008 INTERNATIONAL ELECTROTECHNICAL COMMISSION _ LOW-VOLTAGE ELECTRICAL INSTALLATIONS Part 4-43: Protection for safety Pro
30、tection against overcurrent FOREWORD 1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising all national electrotechnical committees (IEC National Committees). The object of IEC is to promote international co-operation on all questions conce
31、rning standardization in the electrical and electronic fields. To this end and in addition to other activities, IEC publishes International Standards, Technical Specifications, Technical Reports, Publicly Available Specifications (PAS) and Guides (hereafter referred to as “IEC Publication(s)”). Thei
32、r preparation is entrusted to technical committees; any IEC National Committee interested in the subject dealt with may participate in this preparatory work. International, governmental and non-governmental organizations liaising with the IEC also participate in this preparation. IEC collaborates cl
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38、ttees and IEC National Committees for any personal injury, property damage or other damage of any nature whatsoever, whether direct or indirect, or for costs (including legal fees) and expenses arising out of the publication, use of, or reliance upon, this IEC Publication or any other IEC Publicatio
39、ns. 8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is indispensable for the correct application of this publication. 9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of paten
40、t rights. IEC shall not be held responsible for identifying any or all such patent rights. International Standard IEC 60364-4-43 has been prepared by IEC technical committee 64: Electrical installations and protection against electric shock. This third edition cancels and replaces the second edition
41、, published in 2001, and constitutes a technical revision. The main changes with respect to the previous edition are listed below: Annex B “IEC 60364 Parts 1 to 6: Restructuring” deleted. Introduction of new informative Annexes B, C and D. Information concerning flexible cables added to Scope. The w
42、ord “phase” changed to “line” throughout the standard. Requirement not to distribute the neutral in IT systems changed to a NOTE. Requirements added for overload detection for the neutral conductor for harmonic currents. 60364-4-43 IEC:2008 5 Requirement that devices for protection against short-cir
43、cuit current be capable of making as well as breaking short-circuit current added. Information added to clarify protection against overload current. Requirements where devices for protection against overload need not be provided expanded. More examples given where omission of devices for protection
44、against overload is permitted. Requirements where devices for protection against short-circuit need not be provided expanded. Requirements for short-circuit current ratings of busbar trunking systems added. The text of this standard is based on the following documents: FDIS Report on voting 64/1641/
45、FDIS 64/1656/RVD Full information on the voting for the approval of this standard can be found in the report on voting indicated in the above table. This publication has been drafted in accordance with the ISO/IEC Directives, Part 2. The readers attention is drawn to the fact that Annex E lists all
46、of the “in-some-country“ clauses on differing practices of a less permanent nature relating to the subject of this standard. This International Standard has the status of a group safety publication in accordance with IEC Guide 104. A list of all parts in the IEC 60364 series, under the general title
47、 Low-voltage electrical installations, can be found on the IEC website. Future standards in this series will carry the new general title as cited above. Titles of existing standards in this series will be updated at the time of the next edition. The committee has decided that the contents of this pu
48、blication will remain unchanged until the maintenance result date indicated on the IEC web site under “http:/webstore.iec.ch“ in the data related to the specific publication. At this date, the publication will be reconfirmed, withdrawn, replaced by a revised edition, or amended. 6 60364-4-43 IEC:200
49、8 LOW-VOLTAGE ELECTRICAL INSTALLATIONS Part 4-43: Protection for safety Protection against overcurrent 43 Protection against overcurrent 430.1 Scope This part of IEC 60364 provides requirements for the protection of live conductors from the effects of overcurrents. This standard describes how live conductors are protected by one or more devices for the a
