GUIDE ENGINEERING SPECIFICATION

ELECTRICAL GUIDE ENGINEERING SPECIFICATION FOR LOW VOLTAGE METAL ENCLOSED SWITCHGEAR ELECTRICAL GUIDE ENGINEERING SPECIFICATION GUIDE SPEC. NO. REV FOR 3GS ES 902 0 LOW VOLTAGE METAL ENCLOSED SWITCHGEAR Page 1 of pageref totpgs14 CONTENTS 1.0 SCOPE 3 2.0 CODES AND STANDARDS 3 3.0 SERVICE CONDITIONS 3 4.0 ELECTRICAL SYSTEM 4 5.0 STRUCTURAL AND MECHANICAL REQUIREMENTS 4 6.0 CIRCUIT BREAKERS 5 7.0 ISOLATOR AND FUSE COMBINATION UNITS 6 8.0 BUSBARS 6 9.0 EARTHING 7 10.0 SECONDARY WIRING 7 11.0 CABLE TERMINATIONS 8 12.0 BUS DUCT 9 13.0 AUXILIARY SUPPLIES 9 14.0 INSTRUMENT TRANSFORMERS 10 15.0 METERING, PROTECTION, CONTROL AND INDICATION 11 16.0 ANTI-CONDENSATION HEATERS 11 17.0 LABELS 12 18.0 FINISH 12 19.0 SPECIAL TOOLS 12 20.0 SPARES 13 21.0 INSPECTION AND TESTING 13 22.0 SHIPPING, HANDLING AND STORAGE 13 23.0 DRAWINGS AND DATA 14 24.0 DEVIATIONS 14 APPENDICES APP. A INTERNATIONAL STANDARDS APP. B NATIONAL STANDARDS APP. C OUTDOOR ENCLOSURES 1.0 SCOPE 1.1 This specification covers the design, manufacture and testing of industrial type metal enclosed factory assembled switchgear for use in electrical systems of up to 1000 volts. When the switchgear is to be provided as an integrated switchgear/MCC, this specification shall be used in conjunction with the specification for motor control centres. 1.2 Throughout this Specification reference is made to "specified elsewhere or as specified". Details for requirements of this type are to be found on the one line diagram or data sheet as appropriate. 2.0 CODES AND STANDARDS 2.1 The switchgear shall be designed, manufactured and tested in accordance with the latest applicable sections of the IEC codes detailed in Attachment A. By exception the standards listed in Attachment B may be used with the consent of the Buyer. 2.2 The word `should' shall be replaced by `shall' wherever it appears in the reference standards. 2.3 Conflicts between referenced documents shall be identified to the Buyer in writing for resolution. In general the order of precedence is:- SYMBOL 183 \f "Symbol" \s 10 \h One Line Diagram and Schedules (When reference to the one line diagram is made in the following part of this specification, it shall be deemed to include reference to the associated schedules.) SYMBOL 183 \f "Symbol" \s 10 \h Data Sheet (if used) SYMBOL 183 \f "Symbol" \s 10 \h Purchase Order SYMBOL 183 \f "Symbol" \s 10 \h This specification SYMBOL 183 \f "Symbol" \s 10 \h Reference standards 3.0 SERVICE CONDITIONS 3.1 Switchgear shall be rated for operation under service conditions stated on the switchgear one line diagram. The switchgear shall have a design life of at least 20 years and periodic maintenance interval of greater than four years. 4.0 ELECTRICAL SYSTEM 4.1 The electrical arrangement of the switchgear, protection, metering, control, interlocking, inter-tripping, etc. shall be as shown on the switchgear one line diagram. 4.2 All components of the switchgear shall be rated for the electrical system characteristics shown on the one line diagram. Special reference is made in respect of enhanced circuit making requirements and the d.c.component of fault current at breaking. 5.0 STRUCTURAL AND MECHANICAL REQUIREMENTS 5.1 Switchgear cubicles shall be metal enclosed, free standing, floor mounting, flush fronted and arranged to form a single structure with a common busbar assembly. It shall not exceed a height of 2.5m. Assemblies shall be form 4 construction to IEC 439. 5.2 Switchgear and busbars shall be arranged to permit future extension at either end. 5.3 The structure, including doors and panels, shall be capable of withstanding the internal pressure created by faults within the structure (equal to the maximum fault-current rating) without danger to the operating personnel. 5.4 The structure shall be provided with barriers to prevent the transfer of ionised gases between compartments. 5.5 Structures shall be self ventilating. 5.6 Interlocks, busbar shutters, covers, etc. shall be provided to prevent incorrect or unsafe operation, and to prevent access to live parts. 5.7 Switchgear shall be designed and constructed to facilitate inspection, cleaning, repair and maintenance and to ensure absolute safety during operation, inspection and maintenance. 5.8 Similar parts and components shall be interchangeable. 5.9 The overall switchgear enclosure shall have a degree of protection as stated on the one line diagram. When the switchgear is specified to be in an outdoor enclosure, the additional requirements of Attachment C to this specification shall apply. 5.10 Outgoing feeder units may be arranged in tier formation, with circuit breakers limited to a maximum of 4 high. 5.11 Incoming and bus-section units must be located in non-tiered separate cubicles. 5.12 Any non-equipped spare compartments shall be arranged such that they can be fully equipped without de-energising the switchgear. 6.0 CIRCUIT BREAKERS 6.1 Circuit breakers shall be: SYMBOL 183 \f "Symbol" \s 10 \h Withdrawable SYMBOL 183 \f "Symbol" \s 10 \h Of air break design SYMBOL 183 \f "Symbol" \s 10 \h Have the number of poles specified on the system one line diagram SYMBOL 183 \f "Symbol" \s 10 \h Suitable for uninterrupted duty and utilisation category B to IEC 947 or equivalent standard 6.2 Circuit breaker operating mechanisms shall be as stated on the switchgear one line diagram. 6.3 Tripping, closing, control and indication supplies for circuit breakers shall be as shown on the switchgear one line diagram. 6.4 Circuit breakers shall be supplied with a means to manually operate the open/close mechanism. 6.5 Test facilities shall be provided to permit operation of the circuit breaker whilst in the test/isolated position. 6.6 Circuit breakers shall be provided with two normally open and two normally closed spare, auxiliary contacts wired out to terminals. 6.7 Circuit breaker carriages shall be provided with normally open and normally closed switches wired out to terminals for: SYMBOL 183 \f "Symbol" \s 10 \h Circuit breaker in service position. SYMBOL 183 \f "Symbol" \s 10 \h Circuit breaker in withdrawn position. 6.8 Withdrawable circuit breakers shall: 6.8.1 Be interlocked to prevent: SYMBOL 183 \f "Symbol" \s 10 \h The breaker being inserted into the service position unless it is open. SYMBOL 183 \f "Symbol" \s 10 \h The breaker being withdrawn from the service position unless it is open. SYMBOL 183 \f "Symbol" \s 10 \h The breaker being closed unless it is fully in the service, or withdrawn/test position. SYMBOL 183 \f "Symbol" \s 10 \h Remote operation whilst in the withdrawn/test position. 6.8.2 Be fitted with busbar and circuit shutters: SYMBOL 183 \f "Symbol" \s 10 \h With padlocking facilities. SYMBOL 183 \f "Symbol" \s 10 \h Coloured red for busbar and yellow for circuit. For bus-section and coupler applications the shutters shall be labelled with the busbar number. SYMBOL 183 \f "Symbol" \s 10 \h If metal construction be effectively earthed to the main housing. SYMBOL 183 \f "Symbol" \s 10 \h Of the positively driven type, gravity drop shutters are not acceptable. SYMBOL 183 \f "Symbol" \s 10 \h Capable of being individually operated by hand. 6.8.3 Have provisions for padlocking in the test, earthed and isolated positions and have labels to clearly indicate these positions. 6.8.4 Be provided with an anti-pumping facility in the circuit breaker closing circuit. 7.0 ISOLATOR AND FUSE COMBINATION UNITS 7.1 Isolators and fuse combination units shall: SYMBOL 183 \f "Symbol" \s 10 \h Be of the fixed, air break type SYMBOL 183 \f "Symbol" \s 10 \h Be of the rating and number of poles as stated on the one line diagram SYMBOL 183 \f "Symbol" \s 10 \h Be provided with facilities for padlocking in the `off' position SYMBOL 183 \f "Symbol" \s 10 \h Be of the fault-make, load-break type, unless specified otherwise SYMBOL 183 \f "Symbol" \s 10 \h Be interlocked to prevent the compartment door being opened unless the isolator is in the open position 8.0 BUSBARS 8.1 Busbars and connections shall be manufactured from hard drawn copper. 8.2 Busbars shall be of the same cross sectional area throughout the length of the switchgear. 8.3 Phase and neutral (where specified) busbars shall be run in a separate compartment not requiring access for any other purpose. 8.4 Busbars shall be marked to indicate the phase colouring, which shall be red, yellow, blue (unless otherwise specified). 8.5 Busbars, at bus section switches, shall be arranged to permit safe work on one bus whilst the other remains energised. In addition it shall not be possible for arcs to transfer across busbars in the bus section cubicle. 8.6 An earth busbar shall be provided along the full length of the switchgear structure with provision for earth cable connections at each end. 8.7 Busbars and connections shall be sized, braced and supported to withstand the mechanical forces and thermal effects resulting from the switchgear rated short circuit current and carry certification from a recognised testing authority. 9.0 EARTHING 9.1 All metallic non-current carrying parts of the switchgear shall be bonded together and connected to the switchgear earth busbar. 9.2 All doors shall be bonded to the main structure by means of a flexible copper connection arranged so that it cannot be trapped as the door is opened or closed. 9.3 Withdrawable parts (eg circuit breakers) shall be effectively earthed until they are completely withdrawn with all power and control connections disconnected. 9.4 Provision shall be made, adjacent to the cable termination, for earthing cable armouring to the earth busbar. 10.0 SECONDARY WIRING 10.1 Secondary wiring shall be PVC insulated 600 volts grade. 10.2 Secondary wiring within the switchgear shall be securely held in position (either loomed or run in conduit/trunking). Where wiring passes through compartments it shall be run in conduit/trunking and if metallic bonded to the main frame. 10.3 Secondary wiring layout shall permit alterations to individual circuits without requiring shutdown of the complete switchgear. 10.4 Bus wires for closing, tripping, control, indication, heaters etc. shall be run within the switchgear and individually fused. 10.5 Wiring identification shall be by numbered and/or lettered interlocking sleeve ferrules, of insulating material adjacent to the terminals. They shall be indelibly marked and removal without disconnecting the wire from its terminal shall not be possible. 10.6 Flexible cables shall be used for connections on door mounted equipment. Wiring shall be loomed, wrapped in flexible conduit and be firmly clamped at both ends to prevent movement at terminations. 10.7 All wiring for external connections shall be brought out to individual terminals on a readily accessible terminal block. 10.8 No more than two wires shall be connected to a terminal. 11.0 CABLE TERMINATIONS 11.1 Cable terminating facilities and terminals shall be suitable for the specified cable type and conductor size. 11.2 Terminal blocks shall be arranged and positioned to afford easy access for carrying out external cable termination, testing, inspection and maintenance. There shall be clear space allowed between the terminal block and the cable entry for the spreading and termination of external conductors. 11.3 Terminal blocks shall be mounted in a single deck arrangement. 11.4 The panel wiring shall be on one side of the terminal block only. 11.5 All terminal blocks shall be shrouded or provided with transparent covers. Pinch screw type terminals are not acceptable. 11.6 Terminals for different voltages shall be separated by partitions. 11.7 Terminal boxes(where specified) shall be suitable for dry type terminations unless otherwise specified. 11.8 A terminal box or chamber with undrilled gland-plate or entry panel of sufficient dimensions to terminate the specified cables shall be provided. Direction of cable entry shall be as specified on the one line diagram. 11.9 Positioning of cable terminations shall avoid obstruction of other cable terminations, removable covers, etc. and provide for easy access for terminating cables. 11.10 Cable supports shall be provided by the Seller to avoid undue strain on the cable termination. 11.11 Termination of single core cables shall be through a non magnetic metal panel or gland plate and provision made for bonding and earthing any armour and/or concentric ground conductors. 12.0 BUS DUCT 12.1 When specified on the one line diagram, it shall be the switchgear Seller's responsibility to furnish and coordinate the bus ducts to the respective switchgear assemblies and to the supply transformers or other associated equipment. Dimensions and details of transformer throats or other equipment connections will be supplied to the switchgear Seller by Buyer. 13.0 AUXILIARY SUPPLIES 13.1 Auxiliary supplies (closing, tripping, control, indication, heaters, etc) shall be in accordance with the one line diagram. 13.2 Circuit breaker closing power shall be ac or dc supplied from voltage transformers connected to the supply side of the incoming circuit breakers unless specified otherwise, . Where there is more than one incomer, interlocks/changeover facilities shall be provided to permit closing power to be available to all circuit breakers when the switchgear is being supplied by one incomer only (with the bus section circuit breaker closed). 13.3 Circuit breaker tripping, control and indication power shall be supplied from suitably rated dc supply units. Where dc supply units are not in the Sellers scope, then he shall specify the standing load, peak load and permissible voltage variation. 13.4 All auxiliary supplies shall be individually fused/protected within each circuit breaker housing. 13.5 For shunt trip circuits the protection shall be rated at least 300% of the load. 13.6 Anti-condensation heater supplies shall be fed from a single source for each busbar section. 14.0 INSTRUMENT TRANSFORMERS 14.1 Voltage and current transformers of ratio, output, class and accuracy for protection and metering, shall be provided as shown on the one line diagram. 14.2 The Seller shall provide details of ratio, output, class and accuracy for all instrument transformers in his supply. 14.3 The secondary windings of instrument transformers shall be earthed at one point through a removable link, with provision for attaching test links. 14.4 Current transformers shall be bar type and rated to withstand the thermal and magnetic stresses resulting from through fault current equal to the switchgear fault rating.In exceptional circumstances the buyer may authorise the use of wound C.T.s where bar type cannot provide a suitable ratio. 14.5 Where current balance protection is specified the Seller shall provide calculations together with current transformer magnetisation curves to prove the through fault stability of the protection up to the switchgear fault rating. 14.6 Current transformers required for current balance protection schemes and not mounted within the switchgear shall be supplied loose by the Seller (unless otherwise stated). 14.7 Shorting terminals for current transformers shall be provided at the outgoing terminals where external connections are required. 14.8 Voltage transformers shall be located as shown on the one line diagram. 14.9 Voltage transformer primary and secondary winding shall be protected by High Rupturing Capacity Cartridge fuses. 14.10 Voltage transformers shall have provisions for isolation from the energised busbars. 14.11 Instrument transformer nameplates shall be fixed in a position so that details can easily be read when fitted in the cubicle. 15.0 METERING, PROTECTION, CONTROL AND INDICATION 15.1 Metering, protection and control shall be provided as shown on the one line diagram. 15.2 Meters and relays shall be flush mounting and fitted on the front of the switchgear. 15.3 Meters and relays shall be capable of withstanding without damage the secondary current associated with the switchgear rated fault current flowing in the primary of current transformers. 15.4 External zero adjustment shall be possible on all indicating instruments to facilitate adjustment without dismantling the instrument. Ammeters shall be scaled such that full load corresponds to between 50 and 80% of the angular deflection. 15.5 Protective relays shall, wherever possible, be of the draw-out type with hand reset operation indicator and be fitted with test blocks. 15.6 Voltage free alarm contacts shall be provided for alarms as shown on the one line diagram. 15.7 Indication lamps (green-open, red-closed) and positive drive mechanical position indicators shall be provided for each circuit breaker. 15.8 For electrically operated breakers a selector switch shall be provided so that circuit breakers can be closed at either:- SYMBOL 183 \f "Symbol" \s 10 \h The switchgear. SYMBOL 183 \f "Symbol" \s 10 \h Remote control desk/panel. It shall be possible to mechanically trip circuit breakers at the switchgear or electrically trip from any operating position. 15.9 When the circuit breaker is in the test, withdrawn or earth position, operation shall only be possible from the switchgear. 16.0 ANTI-CONDENSATION HEATERS 16.1 Thermostatically controlled heaters suitably rated to prevent condensation shall be provided within the switchgear and auxiliary cubicles. 17.0 LABELS 17.1 Switchgear cubicles and components shall be identified by labels. Cubicle and compartment label designations (located at front and rear of panel) shall be in accordance with the one line diagram. All withdrawable components shall have a circuit label. 17.2 A main nameplate shall be affixed in a prominent position on each switchboard giving the following information: SYMBOL 183 \f "Symbol" \s 10 \h Manufacturers name and type. SYMBOL 183 \f "Symbol" \s 10 \h Switchboard Tag Number. SYMBOL 183 \f "Symbol" \s 10 \h System voltage, phases, wires and frequency. SYMBOL 183 \f "Symbol" \s 10 \h Rated fault current. SYMBOL 183 \f "Symbol" \s 10 \h Busbar rating. SYMBOL 183 \f "Symbol" \s 10 \h Year of manufacture. SYMBOL 183 \f "Symbol" \s 10 \h Purchasers name. SYMBOL 183 \f "Symbol" \s 10 \h Order Item No. 17.3 Each circuit shall be fitted with a label giving the following information:- SYMBOL 183 \f "Symbol" \s 10 \h Equipment tag number and circuit designation. 17.4 Labels shall have black characters on a white background and be made of a non-corrodible material. 17.5 Labels shall be affixed by means other than adhesive. 18.0 FINISH 18.1 The colour and finish shall be in accordance with the Manufacturers standards for the service conditions specified. 19.0 SPECIAL TOOLS 19.1 A complete set of any special tools required for operation, maintenance and testing of the switchgear shall be provided. The seller shall provide a list of special tools, individually priced, with his quotation. A storage box or wall mounted rack shall be provided together with a breaker lifting/transport dolly. 20.0 SPARES 20.1 The Seller shall provide with his quotation, separate priced lists of recommended commissioning and operating spares. 20.2 Commissioning spares (approved by the Buyer) shall be included with the switchboard. 21.0 INSPECTION AND TESTING 21.1 The Seller shall provide test certificates with his quotation for each design and rating of switchgear for Type and Routine tests carried out on the switchgear. Tests shall be those listed in the relevant standards (refer to paragraph 2.0). The tests shall be for the precise cubicle configuration proposed, including any adaptor units between switchgear and MCC. 21.2 The Buyer reserves the right to witness the following tests:- SYMBOL 183 \f "Symbol" \s 10 \h Routine tests on all switchgear/components as specified in the relevant standards (refer to paragraph 2.0). SYMBOL 183 \f "Symbol" \s 10 \h Operational (electrical and mechanical) tests on all components. SYMBOL 183 \f "Symbol" \s 10 \h Protection operation by primary injection of current and voltage as required. SYMBOL 183 \f "Symbol" \s 10 \h Interchangeability test. SYMBOL 183 \f "Symbol" \s 10 \h Type tests where carried out for this application. (Certificate for witnessed tests shall be available for signature on the day of the test.) 21.3 The Seller shall give two weeks notice of tests prior to commencement. 21.4 The Buyer reserves the right to inspect switchgear at the Manufacturer's works prior to despatch to prove compliance with specification. 22.0 SHIPPING, HANDLING AND STORAGE 22.1 Switchgear shall be shipped in sections to suit ease of handling for transportation and installation. 22.2 Each shipping section shall be provided with supports in the form of steel sections, lifting eyes etc. to maintain alignment of parts during shipping, handling, hoisting and installation. Location of lifting points shall be clearly marked on shipping containers and on drawings. Each shipping section shall have its weight clearly marked on the container. 22.3 Preparation for shipment shall protect the switchgear auxiliary devices, accessories, etc. against corrosion, dampness, breakage or vibration injury during transportation and handling. 22.4 Each shipping container shall be identified with the contents, purchase order number and item number. 22.5 Instructions shall be provided for reassembly of sections in the field. 23.0 DRAWINGS AND DATA 23.1 The Seller shall provide drawings and data in accordance with:- SYMBOL 183 \f "Symbol" \s 10 \h The purchase requisition and it's attachments including "vendor drawing and data requirements". SYMBOL 183 \f "Symbol" \s 10 \h Instructions to Sellers. 24.0 DEVIATIONS 24.1 Deviations from this specification are only acceptable where the Seller has listed in his quotation the requirements he cannot or does not wish to comply with and the Buyer has accepted, in writing, the deviations before order is placed. If the manufacturer is also to offer alternatives resulting in technical or price advantages he should submit a supplement to the main tender. 24.2 In the absence of a list of deviations, it will be assumed by the Buyer that the Seller complies fully with this specification. ATTACHMENT A INTERNATIONAL STANDARDS IEC STANDARDS IEC 44 Instrument transformers. IEC 51 Direct acting indicating analogue electrical measuring instruments and their accessories. IEC 73 Colours of indicator lights and push buttons. IEC 185 Current transformers. IEC 186 Voltage transformers. IEC 255 Electrical relays. IEC 269 Low-voltage fuses. IEC 288 PVC-insulated cables for switchgear and controlgear wiring. IEC 417 Graphical symbols for use on equipment. IEC 439 Low-voltage switchgear and control gear assemblies. IEC 445 Identification of equipment terminals and of terminations of certain designated conductors. Including general rules for an alphanumeric system. IEC 521 Alternating current watthour meters. IEC 715 Dimensions of low-voltage switchgear and controlgear. Standardized mounting on rails for mechanical support of electrical devices in switchgear and controlgear installations. IEC 947 Low-voltage switchgear and control gear. ATTACHMENT B NATIONAL STANDARDS BRITISH STANDARDS BS 88 Cartridge fuses for voltages up to and including 1000V ac and 1500V dc. BS 89 Direct acting indicating analogue electrical measuring instruments and their accessories. BS 142 Electrical protection relays. BS 7626 Current transformers. BS 7625 Voltage transformers. BS 5472 Low-voltage switchgear and controlgear for industrial use. Terminal markings and distinctive numbers. General rules. BS 5486 Low-voltage switchgear and controlgear assemblies. BS 5685 Electricity meters BS 6231 PVC insulated cables for switchgear and controlgear wiring. BS.EN 60947 Low-voltage switchgear and controlgear. ATTACHMENT B NATIONAL STANDARDS AMERICAN STANDARDS ANSI C37.13 Low-voltage AC Power Circuit Breakers Used in Enclosures. ANSI C37.16 Switchgear - Low-voltage Power Circuit Breakers and AC Power Circuit Protectors. ANSI C37.20.1 Metal-enclosed Low-voltage Power Circuit Breaker Switchgear. ANSI C37.46 Power Fuses and Fuse Disconnecting Switches. ANSI C37.50 Switchgear - Low-voltage AC Power Circuit Breakers Used in Enclosures. ANSI C37.51 Switchgear - Metal Enclosed Low-voltage AC Power Circuit Breaker Switchgear Assemblies. ANSI C37.55 Switchgear - Metal Clad Assemblies. ANSI C37.90 Relays and Relay Systems Associated with Electrical Power Apparatus. ANSI C57.13 Requirements for Instrument Transformers. NEMA AB 1 Moulded Case Circuit Breakers and Moulded Case Switches. NEMA SG 3 Low-voltage Power Circuit Breakers. NEMA SG 5 Power Switchgear Assemblies. NFPA 70 National Electrical Code. UL 94 Safety tests for Flammability of Plastic Materials for Parts in Devices and Appliances. UL 1558 Safety Metal Enclosed Low-voltage Power Circuit Breaker Switchgear. ATTACHMENT C OUTDOOR ENCLOSURES C.1 Enclosures shall be weatherproof and be fabricated from free-standing steel frames and steel panels with doors formed to provide a strong and rigid structure with degree of protection as stated on the one line diagram. C.2 Gaskets shall be held in metal containers (channel, etc). The roof shall be sloped to provide drainage in a direction away from the doors. C.3 Removable panels shall be secured with captive slotted or shaped-head fasteners, machine screws or machine bolts engaging captive nuts or tapped holes in structural members. Self-tapping sheet metal screws shall not be used. C.4 Walk-in (protected aisle) enclosures shall be provided with a 750mm minimum width outer door at each end, each fitted with inside, quick-release latch mechanisms and with flush, cylinder-type locks. All cylinders shall be operable by the same key and shall be of the type as specified. C.5 Aisle-less enclosures shall have individual outer doors of 600mm minimum width for each section. Doors shall have provision for padlocking. C.6 Door stops shall be provided to maintain doors in the open position and a stop release shall be provided no higher than 1.8m above the floor. Door latches shall engage the steel frame at three points (top, bottom and side) to latch the doors closed, and shall have a rolling or smooth sliding action when engaging the frame to aid in operating the latches. C.7 All exposed handles, screws, and hinges shall be noncorrosive material, or shall be galvanized or plated with cadmium or chromium. C.8 Enclosures shall have louvred ventilation openings at the bottom, unless designed to be non-ventilated. Such openings shall be equipped with replaceable filter elements. The filter elements shall be accessible for replacement while the equipment is in normal service. C.9 When specified, thermostatically controlled ventilation fans and/or heaters shall be provided to maintain a preset maximum/minimum temperature within the enclosures. C.10 Enclosures shall be provided with a totally enclosed base constructed of 100mm minimum channel or I-Beam. Panelling shall stop a minimum of 75mm above bottom of base. C.11 Each enclosure shall be primed and chemically treated to prevent rust, and painted inside and out per manufacturer's standard unless specified otherwise on the Data Sheets. C.12 Illumination controlled by toggle or door switches shall be provided in all outdoor equipment, unless otherwise specified. Switches shall be identified with engraved nameplates. two-way switches for fluorescent lighting in protected aisle enclosures shall be located beside the door at each end. Minimum illumination shall be 300 Lux on the vertical panels 1m above the floor. C.13 At least one receptacle power outlet shall be provided inside each outdoor enclosure. Where an outdoor assembly includes four or more vertical sections, at least two receptacles shall be furnished, one at each end. Maximum distance between receptacles shall not exceed 9m. C.14 When external power is specified for space heaters, lights and receptacles, isolating switches or circuit breakers shall be provided for each circuit. These devices shall be completely wired and connected to readily accessible, isolated terminal strips for connection of external power wiring. All wiring in the same cableway shall be insulated for the highest voltage wire in the cableway. Page PAGE 14 of 14 3GS ES 902 Rev. 0 Page CPAGE2 of pageref totpgc2 =