1、BRITISH STANDARD BS EN 60950-21:2003 Information technology equipment Safety Part 21: Remote power feeding The European Standard EN 60950-21:2003 has the status of a British Standard ICS 35.020 BS EN 60950-21:2003 This British Standard was published under the authority of the Standards Policy and St
2、rategy Committee on 31 October 2003 BSI 31 October 2003 ISBN 0 580 42840 0 National foreword This British Standard is the official English language version of EN 60950-21:2003, including Corrigendum August 2003. It is identical with IEC 60950-21:2002. The UK participation in its preparation was entr
3、usted to Technical Committee EPL/108, Safety for audio/video and similar technology, information technology and communication technology equipment, which has the responsibility to: A list of organizations represented on this committee can be obtained on request to its secretary. Cross-references The
4、 British Standards which implement international or European publications referred to in this document may be found in the BSI Catalogue under the section entitled “International Standards Correspondence Index”, or by using the “Search” facility of the BSI Electronic Catalogue or of British Standard
5、s Online. This publication does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. aid enquirers to understand the text; present to the res
6、ponsible European committee any enquiries on the interpretation, or proposals for change, and keep the UK interests informed; monitor related international and European developments and promulgate them in the UK. Summary of pages This document comprises a front cover, an inside front cover, the EN t
7、itle page, pages 2 to 19 and a back cover. The BSI copyright notice displayed in this document indicates when the document was last issued. Amendments issued since publication Amd. No. Date CommentsEUROPEAN STANDARD EN 60950-21 NORME EUROPENNE EUROPISCHE NORM April 2003 CENELEC European Committee fo
8、r Electrotechnical Standardization Comit Europen de Normalisation Electrotechnique Europisches Komitee fr Elektrotechnische Normung Central Secretariat: rue de Stassart 35, B - 1050 Brussels 2003 CENELEC - All rights of exploitation in any form and by any means reserved worldwide for CENELEC members
9、. Ref. No. EN 60950-21:2003 E ICS 35.020 Incorporating Corrigendum August 2003 English version Information technology equipment Safety Part 21: Remote power feeding (IEC 60950-21:2002) Matriels de traitement de linformation - Scurit Partie 21: Tlalimentation (CEI 60950-21:2002) Einrichtungen der Inf
10、ormationstechnik - Sicherheit Teil 21: Fernspeisung (IEC 60950-21:2002) This European Standard was approved by CENELEC on 2003-03-01. CENELEC members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Standard the status of a nationa
11、l standard without any alteration. Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the Central Secretariat or to any CENELEC member. This European Standard exists in three official versions (English, French, German). A version in a
12、ny other language made by translation under the responsibility of a CENELEC member into its own language and notified to the Central Secretariat has the same status as the official versions. CENELEC members are the national electrotechnical committees of Austria, Belgium, Czech Republic, Denmark, Fi
13、nland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Luxembourg, Malta, Netherlands, Norway, Portugal, Slovakia, Spain, Sweden, Switzerland and United Kingdom. EN 65900-1202:30 - - 2 Foreword The text of document 108/22/FDIS, future edition 1 of IEC 60950-21 , prepared by IEC TC 108, Sa
14、fety of electronic equipment within the field of audio/video, information technology and communication technology, was submitted to the IEC-CENELEC parallel vote and was approved by CENELEC as EN 60950-21 on 2003-03-01. The following dates were fixed: latest date by which the EN has to be implemente
15、d at national level by publication of an identical national standard or by endorsement (dop) 2003-12-01 latest date by which the national standards conflicting with the EN have to be withdrawn (dow) 2006-07-01 In this standard, the following print types are used: - requirements proper and normative
16、annexes: in roman type; - compliance statements and test specifications: in italic type; - notes and other informative matter: in smaller roman type; - normative conditions within tables: in smaller roman type; - terms that are defined in Clause 3 and in EN 60950-1: SMALL CAPITALS. Annexes designate
17、d “normative“ are part of the body of the standard. Annexes designated “informative“ are given for information only. In this standard, annex ZA is normative and annex A is informative. Annex ZA has been added by CENELEC. _ Endorsement notice The text of the International Standard IEC 60950-21:2002 w
18、as approved by CENELEC as a European Standard without any modification. _ Page2 EN6095021:2003069-0521 IE:C2002 3 CONTENTS INTRODUCTION.4 1 Scope.5 2 Normative references .5 3 Definitions 5 4 General requirements.6 4.1 Power from a telecommunication network (see also 1.4.11 of IEC 60950-1) 6 4.2 Acc
19、ess to energized parts (see also 2.1.1.1 of IEC 60950-1).6 4.3 Protection in service access areas (see also 2.1.2 of IEC 60950-1).6 4.4 Protection in restricted access locations (see also 2.1.3 of IEC 60950-1) 6 4.5 Interconnection of equipment 7 4.5.1 General requirements (see also 3.5.1 of IEC 609
20、50-1) 7 4.5.2 Interconnection between RFT circuits (see also 3.5.2 of IEC 60950-1) 7 5 Connection to telecommunication networks 7 6 Remote power feeding7 6.1 RFT-C circuit limits7 6.1.1 Limits under normal operating conditions.8 6.1.2 Limits under single fault conditions8 6.1.3 Limits with one condu
21、ctor earthed .9 6.2 RFT-V circuit limits9 6.2.1 Limits under normal operating conditions.9 6.2.2 Limits under single fault conditions10 6.2.3 Limits with one conductor earthed .10 6.3 Separation from other circuits and parts 10 6.4 Installation instructions11 Annex A (informative) Remote power feedi
22、ng 13 Annex ZA (normative) Normative reference to international publications with their corresponding European publications .18 Bibliography19 Figure 1 Maximum current after a single fault 9 Figure 2 Limits for capacitance values of RFT CIRCUITS or the total system .12 Figure A.1 Example of a remote
23、 power feeding RFT-C system.15 Figure A.2 Example of a remote power feeding RFT-V system.16 Page3 EN6095021:2003069-0521 IE:C2002 4 INTRODUCTION This Part 21 of IEC 60950 is intended to be used with IEC 60950-1, hereafter referred to as “Part 1”. The subclauses of IEC 60950-1 apply as far as reasona
24、ble. Where safety aspects are similar to those of Part 1, the relevant clause or subclause of IEC 60950-1 is shown for reference in parentheses after the clause or subclause title in this Part 21. Where a requirement in this Part 21 refers to a requirement or criterion of Part 1, a specific referenc
25、e to IEC 60950-1 is made. Page4 EN6095021:2003069-0521 IE:C2002 5 INFORMATION TECHNOLOGY EQUIPMENT SAFETY Part 21: Remote power feeding 1 Scope This part of IEC 60950 applies to information technology equipment intended to supply and receive operating power via a TELECOMMUNICATION NETWORK, where the
26、 voltage exceeds the limits for TNV CIRCUITS. 2 Normative references The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any a
27、mendments) applies. IEC 60950-1:2001, Information technology equipment Safety Part 1: General requirements 3 Definitions For the purposes of this International Standard, the terms and definitions given in IEC 60950-1 and the following apply. 3.1 RFT circuit remote feeding telecommunication circuit a
28、 SECONDARY CIRCUIT within the equipment, intended to supply or receive d.c. power via a TELECOMMUNICATION NETWORK at voltages exceeding the limits for TNV CIRCUITS, and on which overvoltages from TELECOMMUNICATION NETWORKS are possible 3.2 RFT-C circuit an RFT CIRCUIT which is so designed and protec
29、ted that under normal operating conditions and single fault conditions, the currents in the circuit do not exceed defined values NOTE The limit values of current under normal operating and single fault conditions are specified in 6.1 3.3 RFT-V circuit an RFT CIRCUIT which is so designed and protecte
30、d that under normal operating conditions and single fault conditions, the voltages are limited and the accessible area of contact is limited NOTE The limit values of voltage under normal operating and single fault conditions are specified in 6.2 Page5 EN6095021:2003069-0521 IE:C2002 6 4 General requ
31、irements 4.1 Power from a telecommunication network (see also 1.4.11 of IEC 60950-1) RFT CIRCUITS normally exceed the limit in 2.3.1 b) of IEC 60950-1 and also exceed 15 VA. See 4.7.2 of IEC 60950-1 regarding the possible need for a FIRE ENCLOSURE. 4.2 Access to energized parts (see also 2.1.1.1 of
32、IEC 60950-1) The equipment shall be so constructed that, in OPERATOR ACCESS AREAS, there is adequate protection against contact with bare parts of RFT CIRCUITS. These requirements apply for all positions of the equipment when it is wired and operated as in normal use. Protection shall be achieved by
33、 insulation or by guarding or by the use of interlocks. Compliance is checked as given in 2.1.1.1 of IEC 60950-1. 4.3 Protection in service access areas (see also 2.1.2 of IEC 60950-1) In a SERVICE ACCESS AREA, bare parts of RFT CIRCUITS shall be located or guarded so that accidental shorting to SEL
34、V CIRCUITS or to TNV CIRCUITS, for example, by TOOLS or test probes used by SERVICE PERSONS, is unlikely. Bare parts of RFT CIRCUITS that involve an energy hazard shall be located or guarded so that unintentional bridging by conductive materials that might be present is unlikely during service opera
35、tions involving other parts of the equipment. Any guards required for compliance with 4.3 shall be easily removable and replaceable if removal is necessary for servicing. Compliance is checked by inspection and measurement. In deciding whether or not unintentional contact is likely, account is taken
36、 of the way a SERVICE PERSON needs to gain access past, or near to, the bare parts in order to service other parts. 4.4 Protection in restricted access locations (see also 2.1.3 of IEC 60950-1) For equipment to be installed in a RESTRICTED ACCESS LOCATION, the requirements for OPERATOR ACCESS AREAS
37、apply, except that contact is permitted with the bare parts of an RFT CIRCUIT by the test finger shown in Figure 2A of IEC 60950-1 (see 2.1.1.1 of IEC 60950-1); however, such parts shall be so located or guarded that unintentional contact is unlikely. Page6 EN6095021:2003069-0521 IE:C2002 7 Bare par
38、ts that involve an energy hazard shall be located or guarded so that unintentional bridging by conductive materials that might be present is unlikely. Compliance is checked by inspection and measurement. In deciding whether or not unintentional contact is likely, account is taken of the need to gain
39、 access past, or near to, the bare parts. 4.5 Interconnection of equipment 4.5.1 General requirements (see also 3.5.1 of IEC 60950-1) Interconnection circuits shall be selected to provide continued conformance to the requirements of Clause 6 for RFT CIRCUITS, after making connections. NOTE It is per
40、mitted for an INTERCONNECTING CABLE to contain more than one type of CIRCUIT (for example, SELV, LIMITED CURRENT, TNV, ELV, RFT, or HAZARDOUS VOLTAGE) provided that they are separated as required by IEC 60950-1 and this standard. 4.5.2 Interconnection between RFT circuits (see also 3.5.2 of IEC 6095
41、0-1) RFT-C CIRCUITS in the supply equipment shall be connected only to RFT-C CIRCUITS in other equipment. RFT-V CIRCUITS in the supply equipment shall be connected only to RFT-V CIRCUITS in other equipment. For compliance, see 6.4 e). 5 Connection to telecommunication networks An RFT CIRCUIT is perm
42、itted to be directly connected to a TELECOMMUNICATION NETWORK. 6 Remote power feeding Access to the conductors of the REMOTE FEEDING TELECOMMUNICATION CIRCUIT is restricted to SERVICE PERSONS. NOTE Clause 6 covers power feeding to remote equipment at voltages in excess of the voltage limits for TNV
43、CIRCUITS. There are two types of circuits as follows: RFT-C CIRCUITS provide for safety by limiting the current to 60 mA d.c. and are presently used in Europe; RFT-V CIRCUITS provide for safety by limiting the voltage to 200 V d.c. and currents to the same limits as in 6.3 of IEC 60950-1, and are pr
44、esently used in North America. See Annex A. 6.1 RFT-C circuit limits NOTE Unless the current limits in 6.1.1, 6.1.2 and 6.1.3 are inherently met, the RFT-C CIRCUIT should have a monitoring and control device (for example, a balance control), that operates in such a way as to maintain the required cu
45、rrent limits. Page7 EN6095021:2003069-0521 IE:C2002 8 6.1.1 Limits under normal operating conditions Under normal operating conditions, an RFT-C CIRCUIT shall comply with all of the following. a) The steady state current that can flow from the RFT-C CIRCUIT supply equipment into the TELECOMMUNICATIO
46、N NETWORK shall not exceed 60 mA d.c. under any load condition. b) The steady state current that can flow from one conductor of the RFT-C CIRCUIT supply equipment through the TELECOMMUNICATION NETWORK to earth shall not exceed 2 mA d.c. c) The RFT-C CIRCUIT shall be limited to the voltage rating of
47、the wiring of the TELECOMMUNICATION NETWORK, if this voltage is known. NOTE 1 If the voltage rating of the wiring of the TELECOMMUNICATION NETWORK is not known, see 6.4 d). d) The voltage rating of the insulation between conductors and from any conductor to earth in an RFT-C CIRCUIT shall be co-ordi
48、nated with the maximum RFT-C CIRCUIT voltage in the RFT-C CIRCUIT supply equipment, if this is known. If this is not known, the insulation shall be suitable for 800 V d.c. NOTE 2 This insulation level also applies to connectors. Compliance is checked by inspection and measurement. Point 6.1.1 b) is
49、checked by using a resistor of 2 000 2 %. 6.1.2 Limits under single fault conditions In the event of a single fault (see 1.4.14 of IEC 60950-1) within RFT-C CIRCUIT supply equipment, or a failure of the insulation between one conductor of the TELECOMMUNICATION NETWORK and earth, the current in an RFT-C CIRCUIT shall not exceed the line-to-earth and line- to-line lim
