1、PUBLISHED DOCUMENTPD CLC/TR 50479:2007Electrical installation guide Selection and erection of electrical equipment Wiring systems Limitation of temperature rise of connecting interfacesICS 13.260; 29.060.10; 91.140.50g49g50g3g38g50g51g60g44g49g42g3g58g44g55g43g50g56g55g3g37g54g44g3g51g40g53g48g44g54
2、g54g44g50g49g3g40g59g38g40g51g55g3g36g54g3g51g40g53g48g44g55g55g40g39g3g37g60g3g38g50g51g60g53g44g42g43g55g3g47g36g58PD CLC/TR 50479:2007This Published Document was published under the authority of the Standards Policy and Strategy Committee on 29 June 2007 BSI 2007ISBN 978 0 580 58735 1National for
3、ewordThis Published Document was published by BSI. It is the UK implementation of CLC/TR 50479:2007. It supersedes PD 6541:1995 which is withdrawn.The UK participation in its preparation was entrusted to Technical Committee JPEL/64, Electrical installations of buildings Joint committee.A list of org
4、anizations represented on this committee can be obtained on request to its secretary.This publication does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application.Amendments issued since publicationAmd. No. Date CommentsTECHNICAL REPORT CL
5、C/TR 50479 RAPPORT TECHNIQUE TECHNISCHER BERICHT March 2007 CENELEC European Committee for Electrotechnical Standardization Comit Europen de Normalisation Electrotechnique Europisches Komitee fr Elektrotechnische Normung Central Secretariat: rue de Stassart 35, B - 1050 Brussels 2007 CENELEC - All r
6、ights of exploitation in any form and by any means reserved worldwide for CENELEC members. Ref. No. CLC/TR 50479:2007 E ICS 13.260; 91.140.50 Supersedes R064-002:1994English version Electrical installation guide - Selection and erection of electrical equipment - Wiring systems - Limitation of temper
7、ature rise of connecting interfaces Guide pour les installations lectriques - Choix et mise en oeuvre des matriels lectriques - Canalisations - Limitation des chauffements dus aux interfaces de connexion Leitfaden fr elektrische Anlagen - Auswahl und Errichtung elektrischer Betriebsmittel - Kabel- u
8、nd Leitungsanlagen - Begrenzung des Temperaturanstiegs bei Schnittstellenanschlssen This Technical Report was approved by CENELEC on 2006-10-09. CENELEC members are the national electrotechnical committees of Austria, Belgium, Bulgaria, Cyprus, the Czech Republic, Denmark, Estonia, Finland, France,
9、Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, the Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and the United Kingdom. Foreword This Technical Report was prepared by SC 64B, Protection against thermal effect
10、s, of Technical Committee CENELEC TC 64, Electrical installations and protection against electric shock. The text of the draft was submitted to a vote and was approved by CENELEC as CLC/TR 50479 on 2006-10-09. This Technical Report supersedes R064-002:1994. _ CLC/TR 50479:2007 2 INTRODUCTION When de
11、signing an installation or during initial verification, it is sometimes observed that the temperatures reached by interfaces between terminals and conductors are higher than those which could be withstood by insulation in normal service. In this case, precautions shall be taken so that the temperatu
12、re attained by terminals in normal service shall not impair effectiveness of the insulation of conductors connected to them or supporting them. See HD 384.5.52 Electrical installations of buildings Part 5: Selection and erection of electrical equipment Chapter 52: Wiring systems. 52.1 General 52.1.1
13、 Scope This Technical Report is for use as a guide for electrical installations. It is applicable to the limitation of temperature rises of connecting interfaces. 52.1.2 Normative references The following referenced documents are indispensable for the application of this document. For dated referenc
14、es, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. EN 60439-1:1999, Low-voltage switchgear and controlgear assemblies - Part 1: Type-tested and partially type-tested assemblies (IEC 60439-1:1999) EN 60439-3:19
15、91, Low-voltage switchgear and controlgear assemblies - Part 3: Particular requirements for low-voltage switchgear and controlgear assemblies intended to be installed in places where unskilled persons have access for their use - Distribution boards (IEC 60439-3:1990, modified) HD 384.5.523 S2:2001,
16、Electrical installations of buildings - Part 5: Selection and erection of electrical equipment - Section 523: Current-carrying capacities in wiring systems (IEC 60364-5-523:1999, modified) CLC/TR 60890:2002, A method of temperature-rise assessment by extrapolation for partially type-tested assemblie
17、s (PTTA) of low-voltage switchgear and controlgear (IEC 60890:1987 + corr. 1988 + A1:1995) IEC/TR 60943:1998, Guidance concerning the permissible temperature rise for parts of electrical equipment, in particular for terminals 52.2 Maximum temperatures of terminals in normal service conditions 52.2.1
18、 The temperature of a terminal is the sum of the ambient temperature and its temperature rise in normal service. Product standards give conventional limit values for temperature rise under defined test conditions, but do not indicate, in general, limits for permissible temperature rises in service c
19、onditions. Relevant standards in this respect are EN 60439-1, EN 60439-3 and CLC/TR 60890. 52.2.2 The temperatures of terminals are affected by the heat dissipated in normal service by the equipment. This heat may be caused by internal losses dissipated in the equipment and by neighbouring internal
20、and external heat sources, if any. The temperatures of terminals are also related to the way in which they are used, which could affect their electrical resistance and dissipation of heat. CLC/TR 50479:2007 3 52.2.3 Compatibility between temperatures of terminals of equipment and temperatures permit
21、ted for the insulation of the conductors and cables shall be obtained by appropriate arrangement during installation. Clauses, subclauses Recommendations 52.3 Means for limiting temperatures of terminals in service or their effects Recommendations for the choice of methods for limiting temperatures
22、of terminals in service on their effects Recommendations are given below on the selection of methods according to local conditions of installation, practicability of installation, nature of equipment. 52.3.1 Temperatures of terminals can be limited by one or more of the following measures: 52.3.1.1
23、Limitation of contents of enclosures (cubicles, cabinets, trunkings, conduits) The limitation of contents of trunkings and conduits is recommended when a great number of circuits issue from the same panel ; in this case it is preferable to use several runs of trunking or conduit. 52.3.1.2 Spacing be
24、tween equipment in order to improve natural ventilation Spacing between adjacent equipment permits better dissipation of heat. It is necessary to refer to manufacturers instructions. This solution is especially recommended when a great number of items of equipment are installed in the same enclosure
25、 (cubicle or cabinet). 52.3.1.3 Appropriate arrangement of equipment dissipating heat inside enclosures It is recommended that equipment-dissipating heat is installed in an appropriate way so that the correct operation of other equipment will not be impaired. Other means, such as the interposition o
26、f screens or deflectors, may be used for this purpose. 52.3.1.4 Natural or forced ventilation or air-conditioning of cubicles, cabinets or locations. Forced ventilation of the equipment may be necessary in specific applications, for examples to protect against ingress of dust. 52.3.1.5 Derating of e
27、quipment by use of equipment having higher rated current, consequently dissipating less heat. Derating of equipment can be used to reduce the temperature of terminals, provided that such derating is permitted for the equipment. 52.3.1.6 Selection of material for enclosures of cubicles or cabinets in
28、 which terminals are installed, in order to improve the thermal dissipation. 52.3.1.7 Maintenance of correct clamping of conductors in the terminals. Arrangements shall be made to ensure the maintenance of clamping pressure of conductors in their terminals. Such arrangements may be built-in (for exa
29、mple, use of resilient connections) or result from instructions for the inspection of the installation. CLC/TR 50479:2007 4 Clauses, subclauses Recommendations 52.3.2 The effects of temperature rise of terminals in normal service can be limited by one or more of the following means: 52.3.2.1 Selecti
30、on of the insulation of conductors in relation to the presumed temperatures rises. Permissible temperatures in steady-state service for some types of Insulation of conductors are determined by TC 20: If elastomeric insulation rather than thermoplastic is used in order to utilize their higher thermal
31、 ratings, it may be necessary to derate the equipment to which they are connected Ordinary EPR 60C PVC normal 70C PVC temperature resistent 90C XLPE 90C Silicone rubler 180C EVA rubler 110C Polyolefin halogen free 90C Current-carrying capacities of conductors, the values of which are given in tables
32、 of HD 384.5.523, are calculated so that the temperature on the cores does not exceed the permissible temperature determined by the selection of the insulation. A steady-state service implies that overcurrents are infrequent and of limited duration in order not to affect seriously the life of the in
33、sulation. 52.3.2.2 Connection of a short length of conductor whose cross-sectional area may be chosen to be larger than that required by the current. Increasing the cross-sectional area of conductors for other reasons (voltage drop, withstand of short-circuit currents, reduction of the fault loop im
34、pedance) improves the thermal withstand of the conductors. Interposing of an intermediate terminal outside the equipment enables a conductor of larger cross-section or a higher temperature type of cable to be connected. 52.3.2.3 Replacement of the insulation of the conductors by a sleeve which permi
35、ts a higher temperature or replacement of the conductors by conductors insulated appropriately, for a sufficient length. Insulated conductors which permit temperatures at least to 110C are recommended for the supply to equipment operating at a high temperature, such as some luminaires or heating app
36、liances. 52.3.2.4 Separation of conductors of multicore cables between the end of the sheath and the terminal leads to a decrease in the temperature to a value compatible with the permissible temperature of the insulation of the conductors. Choice of a sufficient length for the separation may be bas
37、ed on experiment or on a calculation according to IEC/TR 60943. _ CLC/TR 50479:2007 5 PD CLC/TR 50479:2007BSI389 Chiswick High RoadLondonW4 4ALBSI British Standards InstitutionBSI is the independent national body responsible for preparing British Standards. It presents the UK view on standards in Eu
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