IEE Wiring Matters | Autumn 08 | www.theiet.org

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SECTION 559 (of BS 7671:2008)luminaires and lighting installationsis a new series of Regulations givingparticular requirements for fixedoutdoor lighting installations, extra-low voltage lighting installations andlighting for display stands.Section 559 includes requirements

from Regulations 553-03 (lampholders)and 553-04 (lighting points) in the 16thEdition. This new section alsoincludes requirements from Section611 (Highway Power Supplies andStreet Furniture) of the 16th Edition.The impact of this new section is

that additional requirements are nowincluded in the Regulations for generallighting including requirements forprotection against fire, connection ofluminaires to the fixed wiring, fixingof the luminaires, requirements forthrough wiring in a luminaire,requirements for control gear,e.g. ballasts and compensationcapacitors. A further new requirementis the need to give consideration tostroboscopic effects.The Regulations for outdoor lighting

installations has been expanded,compared to Section 611 in the 16thEdition, to cover car parks, gardens,parks, places open to the public,illumination of monuments andfloodlighting. Other lightingarrangements specifically mentionedinclude telephone kiosks, bus shelters,advertising panels and town plans,which it is recommended are providedwith additional protection by a30mA RCD.Regulation group 559.11 is a

completely new series of Regulationsthat were not included in the 16thedition covering requirements forextra-low voltage lightinginstallations. The particularrequirements of these Regulationsapply to extra-low voltage lightinginstallations supplied from sourceswith a maximum rated voltage of 50 Vac rms or 120 V dc. The Regulationsinclude requirements for protectionagainst electric shock (SELV),protection against the risk of fire dueto short circuit, types of wiringsystems including special

requirements where bare conductorsare used, the types of transformersand converters and requirements forsuspended systems.

LUMINAIRESProtection against fireRegulation 559.5.1 requires that in theselection and erection of a luminairethe thermal effects of radiant andconvected energy on the surroundingsare to be taken into account, including:(i) the maximum permissible powerdissipated by the lamps(ii) the fire-resistance of adjacentmaterial at the point of installationand in the thermally affected areas(iii) the minimum distance tocombustible materials, includingmaterial in the path of a spotlightbeam.

Luminaires are usually installed onnon-combustible surfaces, defined inBS EN 60598-1 as “material incapable ofsupporting combustion” and taken toinclude metal, plaster and concrete.However, sometimes it may be

Section 559 luminairesand lighting installationsAn overview by Geoff Cronshaw

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Wiring Matters is produced by IET Services Limited, a subsidiary of The Institution of Engineering and Technology (IET), for the IET.Michael Faraday House, Six Hills Way, Stevenage, Herts, SG1 2AY, United Kingdom Tel: +44 (0)1438 313311 Fax: +44 (0)1438 313465

Advertising Sales D Smith +44 (0)1438 767224 daniellesmith@theiet.org | Editor G D Cronshaw +44 (0)1438 767384gcronshaw@theiet.org | Contributing Editors M Coles, J Elliott | Design Sable Media SolutionsIEE Wiring Matters is a quarterly publication from the Institution of Engineering and Technology (IET). The IET is not as a body responsible forthe opinions expressed.

©2008: The Institution of Engineering and Technology. All rights reserved. No part of this publication may be reproduced, stored in a retrievalsystem, or transmitted in any form or by any means without the permission in writing of the publisher. Copying of articles is not permittedexcept for personal and internal use. Multiple copying of the content of this publication without permission is always illegal. Web-offsetprinting by Wyndeham Heron, The Bentall Complex, Colchester Road, Heybridge, Maldon, Essex, UK

Co-operating Organisations The Institution of Engineering & Technology acknowledges the contribution made by the followingorganisations in the preparation of this publication: British Electrotechnical & Allied Manufacturers Association Ltd – P D Galbraith,M H Mullins | Department for Communities and Local Government – I Drummond | Electrical Contractors Association – D Locke,S Burchell | City & Guilds of London Institute – H R Lovegrove | Energy Networks Association – D J Start | Electrical Contractors Associationof Scotland SELECT – D Millar, N McGuiness | Health & Safety Executive – K Morton | Electrical Safety Council | ERA Technology Limited –M Coates | British Cables Association – C Reed | Scottish Building Standards Agency | DTI – D Tee | CORGI – P Collins | GAMBICA –M. Hadley, A. Sedhev | Lighting Association – K KearneyISSN 1749-978-X

necessary to mount luminaires onmaterials that may be considered to beflammable (e.g. wood and wood basedmaterials of more than 2 mm thick)and in such cases a classified luminaireto BS EN 60598 marked with thefollowing symbol should be selected:

Where luminaires are marked withthis symbol, the excessivetemperatures which may arise inoperation, or due to the failure of acomponent, will not cause themounting surface temperature toexceed 90 °C and, thereby, cause a riskof fire. Originally this mark onlycovered luminaires with integralcontrol gear but is now applicable toall luminaires complying with the BSEN 60598 series of standards.Luminaires which cannot comply

with this criterion are required tocarry a warning notice or have thefollowing symbol:

NOTE: These symbols are referencedwithin BS EN 60598-1:2004. However,some of these symbols, at the time of

writing this article are the subject ofchange; the reader is advised to consultthe latest edition of BS EN 60598 forcurrent luminaire markingrequirements.

From a thermal view thetemperature of illuminated objectsis also important and the heat from awrongly placed luminaire caninitiate combustion. Luminaires toBS EN 60598, where required to be so,can also be marked with a symbol toindicate the minimum distance from alighted object and a maximum lampwattage.

The above figure shows minimumdistance from a lighted object (m).Regulations 422.3.1 and 422.4.2 give

the following minimum distances atwhich spotlights and projectors shallbe installed from combustiblematerials:(i) rating up to 100 W - 0.5 m(ii) rating over 100 W up to 300 W - 0.8 m(iii) rating over 300W up to 500W - 1.0 m.

Table 55.2 of BS 7671 gives a fullexplanation of symbols used inluminaires, in controlgear forluminaires and in the installation ofluminaires

Connection of luminairesRegulation 559.6.1.1 has requirementsfor Connection to the fixed wiring.The Regulation states:At each fixed lighting point one of

the following shall be used:(i) A ceiling rose to BS 67(ii) A luminaire supporting coupler toBS 6972 or BS 7001(iii) A batten lampholder or a pendantset to BS EN 60598(iv) A luminaire to BS EN 60598(v) A suitable socket-outlet toBS 1363-2, BS 546 or BS EN 60309-2(vi) A plug-in lighting distribution unitto BS 5733(vii) A connection unit to BS 1363-4(viii) Appropriate terminals enclosedin a box complying with the relevantpart of BS EN 60670 series or BS 4662(ix) A device for connecting aluminaire (DCL) outlet according toIEC 61995-1.

NOTE: In suspended ceilings one plug-in lighting distribution unit may beused for a number of luminaires.

Fixing of the luminairesRegulation 559.6.1.5 requires thatadequate means to fix the luminaireshall be provided.The fixing means may be by

mechanical accessories (e.g. hooks orscrews), boxes or enclosures which areable to support luminaires or supportingdevices for connecting a luminaire.

Luminaire suitablefor direct mountingon normal flammablesurfaces

Luminaire suitablefor direct mountingon non-combustiblesurfaces only

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In places where the fixing means isintended to support a pendantluminaire, the fixing means shall becapable of carrying a mass of not lessthan 5 kg. If the mass of the luminaireis greater than 5 kg, the installer shallensure that the fixing means is capableof supporting the mass of the pendantluminaire.The installation of the fixing means

shall be in accordance with themanufacturer’s instructions.The weight of luminaires and their

eventual accessories shall becompatible with the mechanicalcapability of the ceiling or suspendedceiling or supporting structure whereinstalled.Any cable or cord between the fixing

means and the luminaire shall be

installed so that any expected stressesin the conductors, terminals andterminations will not impair the safetyof the installation.

Through wiring in a luminaireIn some instances, it may be necessaryto link the wiring through theluminaire on to the next luminaire.This method of installation shouldonly be used if the luminaire isdesigned for such practice.A cable for through wiring shall be

selected in accordance with thetemperature information on theluminaire or on the manufacturer’sinstruction sheet, if any, as follows:(i) unless specified in themanufacturer’s instructions, for aluminaire complying with BS EN 60598

but with no temperature marking, heatresistant cables are not required(ii) for a luminaire complyingwith BS EN 60598 but with temperaturemarking, cables suitable for themarked temperature shall be used(iii) in the absence of information,heat-resistant cables and/or insulatedconductors of type H05S-U, H05S-K,H05SJ-K, H05SS-K (BS 6007) orequivalent shall be used.

Stroboscopic effectsStroboscopic effects can be extremelydangerous in particularcircumstances. In the case of lightingfor premises where machines withmoving parts are in operation,consideration shall be given tostroboscopic effects which can give amisleading impression of movingparts being stationary. Such effectsmay be avoided by selectingluminaires with suitable lampcontrolgear, such as high frequencycontrolgear, or by distributing lightingloads across all the phases of a threephase supply.

OUTDOOR LIGHTINGRegulation group 559.10 hasrequirements for outdoor lighting,highway power supplies and streetfurniture. Similar to the 16th Edition,the protective measures of placing outof reach and obstacles must not beused; Regulations 559.10.1 gives anexception. Also the protective measuresnon-conducting location and earth-freelocal equipotential bonding must not beused. A relaxation is permitted giving amaximum disconnection time of 5 s(Regulation 559.10.3.3) for all circuitsfeeding fixed equipment used inhighway power supplies for compliancewith Regulation 411.3.2.3 (TN system)or 411.3.2.4 (TT system).The Regulations now clearly state

in 559.10.3.4 that the earthingconductor of a street electrical fixtureshall have a minimum copperequivalent cross-sectional area not lessthan that of the supply neutral

conductor at that point or not less than 6 mm,whichever is the smaller.Regulation 559.10.3.2 now gives

recommendations for lighting installations inplaces such as telephone kiosks, bus shelters,town plans, etc. and requires that additionalprotection by an RCD having thecharacteristics specified in Regulation 415.1.1is provided.

EXTRA-LOW VOLTAGE LIGHTINGINSTALLATIONSScopeThe particular requirements of theseRegulations apply to extra-low voltagelighting installations supplied fromsources with a maximum rated voltage of50 V a.c. rms or 120 V d.c.

Protection against electric shock (SELV)Regulation 559.11.2 requires that an extra-lowvoltage luminaire without provision for theconnection of a protective conductor shall beinstalled only as part of a SELV system. Theprotective measure FELV is not permitted.

Protection against the risk of firedue to short circuitRegulation group 559.11.4 has particularrequirements for protection against the riskof fire due to short circuit. The Regulationstates:559.11.4.1 Where both the live circuitconductors are uninsulated, either:(i) They shall be provided with a protectivedevice complying with therequirements of Regulation 559.11.4.2, or(ii) The system shall comply withBS EN 60598-2-23.

559.11.4.2 A device providing protectionagainst the risk of fire in accordance withRegulation 559.11.4.1 shall meet the followingrequirements:(i) The device shall continuously monitor thepower demand of the luminaires(ii) The device shall automatically disconnectthe supply circuit within 0.3 s in the case of ashort-circuit or failure which causes a powerincrease of more than 60 W(iii) The device shall provide automaticdisconnection while the supply circuit isoperating with reduced power (for example,

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by gating control or a regulatingprocess or a lamp failure) or if there isa failure which causes a powerincrease of more than 60 W(iv) The device shall provide automaticdisconnection upon connection of thesupply circuit if there is a failurewhich causes a power increase ofmore than 60 W(v) The device shall be fail-safe.

NOTE: Account needs to be taken ofstarting currents.

Bare conductorsIf the nominal voltage does not exceed25 V a.c. or 60 V d.c., bare conductorsmay be used providing that the extra-low voltage lighting installationcomplies with all the followingrequirements:(i) the lighting installation shall bedesigned, and installed or enclosed insuch a way that the risk of a short-circuit is reduced to a minimum, and(ii) the conductors used shall have across-sectional area of at least 4 mm,for mechanical reasons, and(iii) the conductors shall not be notplaced directly on combustiblematerial.

For suspended bare conductors, atleast one conductor and its terminals

shall be insulated for that part of thecircuit between the transformer andthe short-circuit protective device toprevent a short-circuit.

Types of transformers and convertersWhere the SELV source of a SELVlighting system is a safety isolatingtransformer, it should meet therequirements of BS EN 61558-2-6.Regulation 559.11.4.2 requires that thetransformer has a protective device onthe primary side or it should be short-circuit proof and marked with thefollowing symbol:

Where an electronic converter, suchas a switch-mode power supply, is usedto supply an extra-low voltage lightinginstallation, it should comply with BSEN 61347-2-2 bearing the followingsymbol:

Suspended systemsRegulation 559.11.6 has requirementsfor Suspended systems.

Suspension devices for extra-lowvoltage luminaires, includingsupporting conductors, shall becapable of carrying five times themass of the luminaires (includingtheir lamps) intended to be supportedbut not less than 5 kg. Terminationsand connections of conductorsshall be made by screw terminals orscrewless clamping devicescomplying with BS EN 60998-2-1 orBS EN 60998-2-2.Insulation piercing connectors and

termination wires which rely oncounterweights hung over suspendedconductors to maintain the electricalconnection shall not be used. Thesuspended system shall be fixed towalls or ceilings by insulated distancecleats and shall be continuouslyaccessible throughout the route.

CONCLUSIONUnder the 17th Edition, designers andpersons involved in general lighting,fixed outdoor lighting installationsand extra-low voltage lightinginstallations now have detailedrequirements to follow. For furtherinformation consult BS 7671:2008.Also, help is at hand, in the form of

a new edition of IEE Guidance Note 1(Selection & Erection edited by MarkColes) available soon. �