3.12 WIRING DEVICES, DISCONNECTS AND LV
PART 1 GENERAL
3.12.1.1 DESCRIPTION OF WORK:
Wiring devices, lighting switches, socket outlets, cord out lets, automatic and manual lighting control equipment, dimmers, outlet boxes and plates, dry- type LV transformers, disconnect switches etc.
3.12.1.2 STANDARDS:
Components are to be standard manufactured items, uniform and modular complying with one set of Standards, throughout the installations. Where specific items are not to the same Standard, submit catalogues and samples to the Engineer for approval.
3.12.1.3 EQUIPMENT DATA:
Submit data including, but not limited to, detailed literature on all items including manufacturer's name, catalogue number, ratings, specifications, overall dimensions and special features.
3.12.1.4 SHOP AND CONSTRUCTION DRAWINGS:
Submit drawings including, but not limited to, the following:
Exact indication of position of each item and outlet box and fitting layout drawings, with box and equipment types and sizes
- Installation details of special items including LV
- Wiring diagrams of special items
3.12.1.5 SAMPLES:
Submit samples of each type of wiring device for approval, unless otherwise instructed by the Engineer.
3.12.1.6 OUTLET BOXES AND PLATES - GENERALLY
SURFACE OR RECESSED BOXES:
Are to be suitable for the type of related conduit system. Shapes and sizes of boxes are to be of compatible standards as switches, socket outlets and lighting fixtures selected and of various types and mounting methods applicable.
UNUSED OPENINGS:
In outlet boxes are to be closed with knock-out closers manufactured for the purpose.
BLANK PLATES:
Blank plates are to be installed on outlet boxes on which no apparatus is installed or where apparatus installed does not have suitable cover for box. Blank plates for wall outlets are to be attached by a bridge with slots for horizontal and vertical adjustment.
FLOOR OUTLETS AND PLATES:
Are to be water-tight and impact resistant.
3.12.1.7 OUTLET BOXES - METALLIC
RECESSED AND CONCEALED BOXES:
Galvanized pressed steel, with knockouts provided for easy field installation work.Special boxes are to be punched as required on Site.
EXPOSED SURFACE MOUNTED BOXES:
Galvanized cast iron with threaded hubs.
OUTDOOR SURFACE OR RECESSED BOXES:
Galvanized cast iron with threaded hubs and PVC gaskets to ensure water tightness and with stainless steel or non- ferrous, corrosion resistant screws.
FLOOR BOXES:
Watertight, cast iron or non-ferrous material with corrosion resistant finish, adjustable mounting, of standard duty, round or square shape, factory drilled and tapped for required conduit sizes, and with brass cover and flange with brushed finish free from markings other than required for mounting screws.
FLAME - PROOF BOXES:
Malleable iron or cast iron with gas threaded hubs, special covers fitted with silicon rubber gaskets, gas tight, water-tight. Boxes are to comply with the Regulations for explosive areas.
MANUFACTURERS:
Obtain metallic outlet boxes from same manufacturer of conduit or equal, to the Engineer's approval.
3.12.1.9 PLATES AND CORD-OUTLETS
GENERALLY:
To be square, rectangular or round, compatibly designed to cover outlet box and closely fit electrical device, with polished chromium plated recessed head fixing screws. Combination plates are to be used for grouped outlets and devices.
CORD EXTENSION PLATES:
Are to have threaded cord grip bushings of same material and finish as plates.
PLASTIC PLATES:
Heavy gauge, break resistant, pressure molded plastic, white color, for general use .Manufactured by
AVE ITALY
Legrand France
or other equal and approved.
CABLE/CORD OUTLET:
For 45 A, 63 A and 125 A 250 V ratings for connection of power/control cable of fixed appliances. Plate is to have threaded cord grip to anchor cable securely to cover. Box is to include fixed terminal block for termination of cable/cord within.
3.12.1.10 LIGHTING SWITCHES
GENERALLY:
Quick-make, quick-break type with silver alloy contacts in an arc resisting molded base, having toggle rocker or push-button as specified, rated 20 A, 250 V a.c., for inductive or resistive loads up to full rated capacity, arranged for side and back connection.
TYPES:
Single, two-way or intermediate, single pole or double pole, as shown on the Drawings.
GENERAL LIGHTING SWITCH(S1):
Rocker operated, grid-switch with plastic plate cover, for all indoor installations in general. As manufactured by
AVE ITALY
Legrand France
or other equal and approved.
PUSH BUTTON SWITCH (S2):
As type (S1) but with push button (push to make or push to break), single pole 10A.
REMOTE LIGHTING CONTROL PANEL FOR CONTACTOR CONTROL:
Is to be multiple switch assembly with one 'on' and 'off' push button switch and a pilot light for 'on' indication per circuit controlled (remote contactor). Panel and box are to be sheet steel construction, with see-through steel framed acrylic door and trim, provided with handle and lock. Enclosure protection IP 42 to IEC 144.
WEATHERPROOF SWITCH:
10A, 250 V for installation outdoors with weatherproof plate over weatherproof outlet box, with 'on-off' indication and IP-54 enclosure, for use where indicated on the Drawings .As manufactured by
AVE ITALY
Legrand France
or other equal and approved.
DOUBLE POLE SWITCH:
Rated 30 A, 250 V a.c., toggle operated, to BS 3676, plate with label indicating equipment controlled and red pilot light for 'on-off' indication complete with cable/cord out let. As manufactured by M.K. KOPP LEGRAND or other equal and approved.
3.12.1.11 SOCKET OUTLET
GENERALLY:
To have injection molded plastic base with self-adjusting non-expanding contacts to prevent permanent distortion, arranged for side and back connection and with screw terminals accepting at least three parallel branch-circuit wires.
DUPLEX SOCKETS:
Where shown, are to be mounted in parallel under one common plate, with break-off feature for two circuit connection.
PLUGS:
Compatible with type of socket outlet specified. Plugs are to be break resistant, of impact resistant molded insulating material (separable construction), with solid brass pins and cord grip and of shape providing easy hand-grip for plug removal. Supply number equal to 30% of total number of each type of socket outlet supplied.
POWER SOCKET OUTLET: single outlet, 2P+E, polarized, earthing type, rated 2OA.
AVE ITALY
Legrand France
or other equal and approved.
3.12.1.12 DISCONNECTING SWITCHES (SWITCH DISCONNECTORS)
RATING:
500 V, 2 poles, 3 pole or 4 pole, load break, short-circuit make in accordance with IEC 408, utilization category 22 for heating and lighting loads, category 23 for motor circuits and with ampere rating shown on drawings and schedule.
DESIGN:
Non-fusible, air-break switch disconnector, single throw, safety type, housed in separate metallic enclosure with arc quenching devices on each pole.
OPERATING MECHANISM:
Quick-make, quick-break, independent of operator, with ex thermal operating handle mechanically interlocked to prevent opening door unless switch is in open position. Disconnect is to have means of by-passing interlock. Position of handle is to be positive and clearly indicated on cover.
ENCLOSURE:
General purpose sheet steel for indoor use IP 42, weather- proof type, cast- metal or sheet steel for outdoor installations IP 65, unless otherwise required or indicated on the drawings. Locking of operating handle is to be possible in 'open' and 'closed' positions.
MANUFACTURERS:
Obtain switch disconnector from one of the following:
BILL Switchgear Ltd. England
G.E. U.S.A
Westinghouse U.S.A
or other equal and approved ) .
PUSH BUTTON SWITCHES (LS):
Is to be momentary contact, normally open switch with pilot light and red jewellens, rated 3 A, 25 V a.c.
MASTER SELECTOR SWITCH PANEL (MSSP):
Is to comprise a set of push button switches type (LS) assembled in one unit comprising box and cover with individual switch per circuit controlled and one master switch for an all-circuit control.
SYSTEM:
Is to allow local and remote centralized switching of a group of lighting circuits and from any number of individual points. System is to use low- voltage (low current) control circuitry to operate relay switches on the branch circuits.
SYSTEM:
Is to be equal to G.E. remote control products, or similar.
PART2 INSTALLAT ION
3.12.2.1 LOCATIONS:
Electrical drawings generally show approximate locations of outlets and equipment. Exact locations are to be determined from interior finishing and detail drawings. Any condition that would place an outlet in an unsuitable location is to be referred to the Engineer. Locate switches at strike sides of doors, whether shown on the Drawings or not. In locating outlets allow for overhead pipes, ducts, variations in arrangement, thickness of finishing, window trim, paneling and other architectural features.
For outlet boxes and similar equipment are to be uniform within the same or similar areas. Mounting is to be as shown on the Drawings or as approved by the Engineer. Unless otherwise shown or instructed, mount lighting switches and socket outlets generally at 1200 mm and 300 mm from finished floor level, respectively. Mount switches with long dimension vertical and operating handle, if of the toggle type, up when in the ON position.
SINGLE POLE SWITCHES:
Are to switch the phase wire. Do not run neutral wire through switches having neutral shunt or bridge.
ADDITIONAL OUTLETS:
To those shown on the Drawings are to be provided as required by equipment manufacturers for control or other wiring.
EXPOSED OUTLET BOXES:
Securely fasten to wall with machine screws to permanent in sertsor lead anchors.
RECESSED OUTLET BOXES:
Make neat openings in block-work, tiling, marble, stone, finished timber, cladding and other architectural finishing to the satisfaction of the Engineer.
Make allowance for thickness of finishing and use extension rings if required. Repair damaged finishing to original condition before installation of fittings or plates.
APPEARANCE:
Install exposed boxes and plates plumb, square and parallel to finished wall surface. Exposed plates covering recessed boxes are to rest neatly on wall surface without gaps, fully covering the box.
GROUPED OUTLETS:
Arrange neatly so that use of fittings is convenient and clear.
WATERPROOF AND EXPLOSION-PROOF FITTINGS:
Follow manufacturer's instructions for installation and connection to conduit system to fully achieve degree of protection.
DAMAGED FITTINGS:
Reject damaged fittings or plates with damaged finish. Protect fittings and plates against damage after installation and until handed over.
CONNECTION OF APPLIANCES:
- where appliance is designed to adapt directly to outlet box, electrical wiring to incoming terminals in side appliance
- Where appliance is not designed to adapt to outlet box, inert connecting wiring in flexible conduit firmly fixed to outlet box cover plate and to terminal box on appliance.
PART 3 INSPECTION AND TESTS ON SITE
VISUAL INSPECTION:
Fittings and equipment are to be inspected for fixing and workmanship.
MEGGER TESTS:
Are to include switches and socket outlet tests together with insulation resistance of wiring installations.
OPERATION:
Devices will be tested for operation and are to perform as intended at full load without any signs of heating.
EQUIPMENT:
Is to be insulation tested and observed under full-load, for not less than 3days operation, as to undue heating, and performance in general.
END OF THIS SECTION
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