1、 I n t e r n a t i o n a l T e l e c o m m u n i c a t i o n U n i o n ITU-T Series K TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU Supplement 7 (05/2017) SERIES K: PROTECTION AGAINST INTERFERENCE ITU-T K.44 AC supply configurations ITU-T K-series Recommendations Supplement 7 K series Supplement 7
2、 (05/2017) i Supplement 7 to ITU-T K-series Recommendations ITU-T K.44 AC supply configurations Summary Supplement 7 to the ITU-T K-series Recommendations gives an overview of typical alternating current (AC) mains supply configurations known as: IT, TT, TN-C, TN-C-S and TN-S together with wiring pr
3、actices. History Edition Recommendation Approval Study Group Unique ID* 1.0 ITU-T K Suppl. 7 2017-05-24 5 11.1002/1000/13271 Keywords AC, IT, mains supply, MEN, PE, PEN, PME, TN-C, TN-C-S, TN-S, TT. * To access the Recommendation, type the URL http:/handle.itu.int/ in the address field of your web b
4、rowser, followed by the Recommendations unique ID. For example, http:/handle.itu.int/11.1002/1000/11830-en. ii K series Supplement 7 (05/2017) FOREWORD The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications, information and communi
5、cation technologies (ICTs). The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of ITU. ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis. The
6、World Telecommunication Standardization Assembly (WTSA), which meets every four years, establishes the topics for study by the ITU-T study groups which, in turn, produce Recommendations on these topics. The approval of ITU-T Recommendations is covered by the procedure laid down in WTSA Resolution 1.
7、 In some areas of information technology which fall within ITU-Ts purview, the necessary standards are prepared on a collaborative basis with ISO and IEC. NOTE In this publication, the expression “Administration“ is used for conciseness to indicate both a telecommunication administration and a recog
8、nized operating agency. Compliance with this publication is voluntary. However, the publication may contain certain mandatory provisions (to ensure, e.g., interoperability or applicability) and compliance with the publication is achieved when all of these mandatory provisions are met. The words “sha
9、ll“ or some other obligatory language such as “must“ and the negative equivalents are used to express requirements. The use of such words does not suggest that compliance with the publication is required of any party. INTELLECTUAL PROPERTY RIGHTSITU draws attention to the possibility that the practi
10、ce or implementation of this publication may involve the use of a claimed Intellectual Property Right. ITU takes no position concerning the evidence, validity or applicability of claimed Intellectual Property Rights, whether asserted by ITU members or others outside of the publication development pr
11、ocess. As of the date of approval of this publication, ITU had not received notice of intellectual property, protected by patents, which may be required to implement this publication. However, implementers are cautioned that this may not represent the latest information and are therefore strongly ur
12、ged to consult the TSB patent database at http:/www.itu.int/ITU-T/ipr/. ITU 2017 All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the prior written permission of ITU. K series Supplement 7 (05/2017) iii Table of Contents Page 1 Scope . 1 2 Referenc
13、es . 1 3 Definitions 1 3.1 Electrical supply system letter classification terms defined in this Supplement . 1 3.2 AC power distribution wiring terms defined in this Supplement . 1 4 Abbreviations and acronyms 2 5 Conventions 2 6 Example AC distribution systems 2 K series Supplement 7 (05/2017) 1 Su
14、pplement 7 to ITU-T K-series Recommendations ITU-T K.44 AC supply configurations 1 Scope This Supplement defines the AC supply configurations known as: IT, TT, TN-C, TN-C-S and TN-S. Distribution wiring practices used for these AC supply configurations are specified. Circuit examples of six AC distr
15、ibution systems and their wiring practices are given. 2 References None. 3 Definitions 3.1 Electrical supply system letter classification terms defined in this Supplement This Supplement defines the following thermal terms: 3.1.1 IT: Unearthed (isolated) electrical supply system with or without a di
16、stributed neutral and the electrical equipment protective earthing is local to the equipment. 3.1.2 multiple earthed neutral (MEN): Neutral wire is earthed multiple times. 3.1.3 protective multiple earthing (PME): PEN wire is earthed multiple times. 3.1.4 protective earthing (PE): Conductor for equi
17、pment protective earthing. 3.1.5 protective earthing and neutral (PEN): Conductor that is both the earthed neutral conductor and the protective earthing conductor. 3.1.5 TT: Neutral earthed electrical supply system where the neutral is earthed at the source and the electrical equipment protective ea
18、rthing is local to the equipment. 3.1.6 TN-C: Neutral earthed electrical supply system where the neutral conductor is combined with the protective earthing conductor. 3.1.7 TN-C-S: Neutral earthed electrical supply system where, in part of the installation, the neutral conductor is also the protecti
19、ve earthing conductor, and in other parts there are separate neutral and protective earthing conductors. 3.1.8 TN-S: Neutral earthed electrical supply system with separate neutral and protective earthing conductors. 3.2 AC power distribution wiring terms defined in this Supplement This Supplement de
20、fines the following conductor terms: 3.2.1 two-wire single-phase AC system: Single-phase AC system comprising two conductors only, between which the load is connected. NOTE 1 The two conductors are typically referenced as L (Live) and N (Neutral). NOTE 2 Other non-power delivery function wires may b
21、e present or combined such as a protective earthing (PE) conductor. 3.2.2 three-wire single-phase AC system: Single-phase AC system comprising two conductors and a neutral wire, the supply being taken from the two outer conductors or from the neutral wire and either outer conductor, the neutral wire
22、 carrying only the difference-current. NOTE 1 The three conductors are typically referenced as L1 (Live 1), L2 (Live 2) and N (Neutral). 2 K series Supplement 7 (05/2017) NOTE 2 Other non-power delivery function wires may be present or combined such as a protective earthing (PE) conductor. 3.2.3 thr
23、ee-wire three-phase AC system: Three-phase AC system comprising three conductors connected to a three-phase supply. NOTE 1 The three conductors are typically referenced as L1 (Live 1), L2 (Live 2) and L3 (Live 3). NOTE 2 Other non-power delivery function wires may be present such as a protective ear
24、thing (PE) conductor. 3.2.4 four-wire three-phase AC system: Three-phase AC system comprising four conductors of which three are connected to a three-phase supply and the fourth to a neutral point in the source of supply. NOTE 1 The four conductors are typically referenced as L1 (Live 1), L2 (Live 2
25、), L3 (Live 3) and N (Neutral). NOTE 2 Other non-power delivery function wires may be present or combined such as a protective earthing (PE) conductor. 4 Abbreviations and acronyms This Supplement uses the following abbreviations and acronyms: AC Alternating Current MEN Multiple Earthed Neutral PME
26、Protective Multiple Earthing PE Protective Earthing PEN Protective Earthing construction, installation and protection of cables and other elements of outside plant Series M Telecommunication management, including TMN and network maintenance Series N Maintenance: international sound programme and tel
27、evision transmission circuits Series O Specifications of measuring equipment Series P Telephone transmission quality, telephone installations, local line networks Series Q Switching and signalling, and associated measurements and tests Series R Telegraph transmission Series S Telegraph services term
28、inal equipment Series T Terminals for telematic services Series U Telegraph switching Series V Data communication over the telephone network Series X Data networks, open system communications and security Series Y Global information infrastructure, Internet protocol aspects, next-generation networks, Internet of Things and smart cities Series Z Languages and general software aspects for telecommunication systems
