16110.pdf

Dynamic Engineering Consultant Mina Al Arab Precinct -5 MEP Specification

DIV: 16 ELECTRICAL SEC: 16110 1 of 8

16110

RACEWAYS AND FITTINGS

PART 1 GENERAL 1.01 DESCRIPTION OF WORK

A. This Section includes raceways (conduit, trunking) and fittings complete.

B. Related Work Specified Elsewhere: 1. Refer to General Conditions and Appendices and Section 16010. 2. Floor boxes are covered under Section 16140, WIRING DEVICES.

C. Protection: 1. Cap raceways stubbed up, including those in cabinets, immediately upon

their installation. The use of paper, polystyrene or rag wads will not be permitted.

PART 2 PRODUCTS 2.01 MATERIALS

A. Conduits and trunking (Raceways). All conduit and trunking shall be BS approved and conduit used no smaller than 20 mm.

1. Rigid Steel Conduit and Electrical Metallic Tubing: All steel conduit shall

be manufactured by a member of the ASCM and shall be of the galvanised steel finish.

In all instances where steel conduit is specified, it shall be galvanised.

In all instances where galvanised steel conduit is used, the accessories and fixing clips etc. shall also be galvanised. The whole of the conduit system shall be weatherproof and suitable compound shall be applied to all threaded joints. This compound shall be of such a nature that it will not impair the electrical continuity of the conduit system.

2. Flexible Conduit: Flexible steel conduits shall comply with BS 731 Part 1

and shall be Type A (unpacked) for normal atmospheric conditions or Type B for damp situations.

Adaptors shall be of the solid type complying with BS 731 Part 1.

Flexible non-metallic reinforced conduit type conduit shall be of steel wire in helical form over which is drawn a sheath of PVC and an overall covering of



the same material. The sheath shall be coloured black unless otherwise indicated or as directed by the Engineer.

Adaptors may be of PVC or of metal and may be crimped or screwed on to the conduit.

Flexible conduit of PVC shall be used only where the ambient temperature will never exceed 60 deg C (140 deg F).

PVC coated flexible steel conduit shall be used for the final connection of the rigid conduit to the terminal boxes of machines fitted with a means of drive adjustment and/or where vibration is likely to occur.

PVC coated flexible steel conduit shall also be provided to semi-portable equipment where a limited amount of movement is required for cleaning and maintenance purposes.

The above does not apply to small machines normally connected to socket outlets by flexible cable.

Unless specified otherwise, the flexible conduit shall be galvanised and non-watertight where normal conditions are anticipated, but the watertight class shall be used where exposed to the weather or where the conduit is likely to be splashed or subjected to excessive moisture.

Flexible conduit will not be permitted in lieu of sets and bends in the rigid conduit system.

3. PVC Conduit: Rigid PVC conduit and conduit fittings shall comply with BS

4607 Part 1 or Part 2 and shall be high impact heavy-duty grade.

Throughout the conduit shall be of adequate cross section and arranged with suitably sized “draw-in” boxes to allow for easy draw in or out of any one or all of the cables, the number of which shall not exceed that set out in I.E.E. Regulations.

The minimum of diameter of any conduit shall be 20mm.

The conduits with fittings, accessory boxes and fixings shall be fully complete prior to drawing in of cables. Adequate precautions shall be taken to prevent the ingress of direct or moisture but should this occur the conduits shall be swabbed clean before wiring commences.

4. Surface Metal Trunking:

Metal trunking may be approved or specified for use in certain installations instead of multiple conduit runs. The internal free area of the trunking shall be such that the quantity of specified cables shall not occupy more than 45% of the available capacity. In new installations a space factor of 25% shall not be exceeded. All cable trunking installed shall be supplied from an approved



manufacturer. No locally fabricated trunking will be accepted unless it is from a standard product range meeting this Specification and written approval is given by the Engineer.

Trunking shall consist of butting sections not less than 2m long, manufactured from galvanised sheet steel, nominal thickness as follows:

50 x 50mm to be 1.0mm 75 x 50mm to be 1.2mm 75 x 75mm to be 1.2mm 100 x 50mm to be 1.2mm 100 x 75mm to be 1.2mm 100 x 100mm to be 1.2mm 150 x 75mm to be 1.6mm 150 x 100mm to be 1.6mm 150 x 150mm to be 1.6mm 200 x 150mm to be 1.6mm 225 x 150mm to be 1.6mm 300 x 150mm to be 1.6mm

B. Pull Boxes.

1. Provide code gauge galvanized sheet metal sized as per the code or as shown on the Drawings. Provide removable cover on the largest access side of the box unless otherwise detailed. Where cast boxes are specified, provide conduit entrances with threaded hubs. Provide stainless steel screws in all exterior locations and in wet or damp locations. Exterior boxes shall be raintight and gasketed.

PART 3 EXECUTION 3.01 INSTALLATION / APPLICATION / PERFORMANCE / ERECTION

A. Installation:

1. Raceways. Install wiring in metal or rigid PVC raceways. Install raceways concealed, except in mechanical rooms, electrical closets and where indicated on the plans.

Provide rigid or intermediate metal conduit for raceways in hazardous areas, in mechanical equipment rooms, and for exposed installations where subject to damage. (Subject to damage shall include exposed installations where vehicle traffic or similar operations may cause damage to raceway other than rigid or intermediate metal). Provide galvanised steel, or rigid PVC conduit for raceways embedded in concrete, in outside walls, or in refrigerated areas. Provide rigid galvanised steel conduit where exposed to the weather. Provide rigid PVC conduit for raceways in earth or below floor slabs-on-grade. Other raceways may be rigid metal conduit, or electrical metallic tubing at the Contractor's option unless otherwise specified or otherwise prohibited by code. Provide vibration isolation for all raceway connections to motors,



transformers and other equipment subject to vibration. Isolation shall consist of a length of flexible conduit of not less than 300mm for 25 mm conduit and smaller and an additional 150 mm per 25 mm of nominal conduit size for conduits larger than 25 mm.

2. Continuity. Provide metallic raceways continuous from outlet to outlet, and

from outlets to cabinets, junction or pull boxes. Enter and secure conduit to all boxes, to provide electrical continuity from the point of service to outlets. Provide double locknut and bushing on terminals of metallic conduits.

3. Raceways in Earth. Unless otherwise noted on the Drawings, provide rigid

PVC conduit for all raceways in earth or in contact with earth.

4. Raceways Exposed. Run exposed raceways in straight lines at right angles or parallel with walls, beams, or columns.

5. Raceways in Plain Concrete. Do not place raceways in plain concrete, such

as cement toppings on structural floors, without special approval. Install, however, in non-reinforced concrete headers provided for their installation.

6. Raceways in Reinforced Concrete. Do not displace reinforcing steel to

accommodate the installation of raceways and outlet boxes. Do not install outlet boxes in beams or joists. Locate all embedded conduits in the physical center of the particular section of concrete. Provide raceways embedded in reinforced concrete conforming to the following usual types of conditions, unless otherwise accepted by the Engineer. Particular attention is called to the fact that there are many extenuating conditions where the Contractor may be instructed during the course of the Project not to place embedded conduits in certain areas, generally due to the possibility of unsightly cracking or for structural reasons. This instruction does not entitle the Contractor to extra compensation. Special approval will be required for any condition not covered by the following usual conditions.

LOCATION MAXIMUM ALLOWANCE

Columns Displacement of 4 percent of plan area of column.

Floors and Walls Displacement of 1/3 of thickness of concrete,

space not less than three diameters O.C.

Beams and joists Displacement of 1/3 of least dimension, spaced not less than three diameters O.C.

Sleeves through 50 mm maximum pipe size, not less than

Floors and Walls three diameters O.C.



7. Raceways Through Roof. In general raceways through roof seals shall be installed in curbs provided for mechanical equipment. When this is not possible the method of penetration shall utilize suitable pitch pockets of a type acceptable to the Engineer. Submit shop drawings of method to be used.

8. Raceways Entering the Building Below Grade. Provide raceways with

galvanized cast-iron wall entrance seals, having a watertight sealing gland assembly.

9. Raceways in ceiling Spaces. Install raceways in accordance with code

requirements. Raceways shall be galvanised steel in ceiling spaces. Do not anchor or strap raceways to the ceiling support channels. Raceways may be attached to the wire hangars of the suspension system of drop ceilings only if installed in such a manner that the ceiling panels may be removed without interference with the raceway and the wire hangers are sized to carry the additional raceway load. Raceways shall not be secured to the support wires of fire-rated ceiling assemblies.

10. Rigid PVC conduit shall not be used in the following locations:

a. Where exposed to the outside ambient temperature.

b. For the installation of single insulated submain cable. c. Where they may be affected by chemicals to cause deterioration in

their construction (Battery & UPS Rooms). d. The same room as a stand-by diesel generator or fuel tanks. e. Where exposed to view, or above suspended ceilings.

11. Strap: and hangers. Substantially support raceways by straps, suitable clamps or hangers, to provide a rigid installation.

a. Perforated strap hangers and twisted wire attachments will not be

acceptable. Do not support or fasten raceways to other pipe, or in a manner to prevent the ready removal of other pipe.

b. In finished room locations where conduit is exposed on walls use one

hole, malleable iron clamps to support raceways.

c. Supports shall be provided at a maximum spacing of 1.5 metres for galvanized steel conduit and 1.2 metres for high impact PVC conduit.

12. Joints and Connections.

a. Metal Conduits. Make watertight all couplings and threaded

connections in threaded conduit. Cut all joints square. ream smooth, and properly thread. Fit all box connections with a minimum of two approved locknuts and one steel, plastic or fiber bushing forming an approved tight bond with box. Provide locknuts both inside and outside of the enclosure to which the conduit is attached. Use



raintight compression type fittings for electrical metallic tubing systems and use at least one locknut on the inside of each enclosure entry. Provide grounding locknuts or bushing where required in GROUNDING (EARTHING) SYSTEM Specification.

b. PVC Conduits. Make watertight all couplings and connectors in

conduit runs. Utilize solvent cement joints of a type approved by the manufacturer for all couplings and fittings. Provide adapters and locknuts where conduit is attached to metal J boxes, panels, etc.

13. Stub Ups. Extend conduit stubs at least 300 mm above slab or fill, before

connection is made to electrical metallic tubing.

14. Threads. Clean all threads of rigid or galvanised steel conduit. Coat all male threads of all steel conduit installed in concrete with red or white lead immediately before being coupled together.

15. Running Threads. Use couplings in lieu of running threads.

16. Expansion Joints. Provide expansion fittings for embedded raceways or

rigidly supported raceways exceeding 30 meters or crossing building expansion joints. Where embedded raceways cross expansion joints, provide combination deflection/expansion fittings, installed in accordance with manufacturer's recommendations. Provide expansion fittings in rigid PVC raceways in strict accordance with manufacturer's recommendations. Where high impact rigid PVC conduit is installed a manufactured purpose made expansion coupler shall be installed for each 8.0 meter length of conduit run between outlet or draw in boxes. These couplers are double normal length with a shoulder formed 20 mm from one end. One conduit is secured into this end of the coupling with an approved adhesive leaving a spout about 75mm long which is a sliding fit over the other conduit.

17. Exterior Conduits. Install raceways below finished grade at code depth.

18. Concrete Encased Ducts.

a. Provide only where specifically indicated on the Drawings or

otherwise required by code. Provide rigid PVC conduit for all ducts unless indicated otherwise on the Drawings.

b. Grade trenches and ducts to provide a minimum 75 mm slope for each 30 m of duct.

c. Multiple conduit runs or banks shall be supported on preformed, non-metallic separators. Any separator containing metal shall have the metal non-continuous and shall not form a magnetic loop in any manner. Spacing between separators shall be close enough to prevent sagging of conduits and breaking of couplings and watertight seals. Separators shall also be spaced to keep deformation of conduit at the separators to 2.5 mm or less. Separators shall be secured with cords where necessary and no tie wires, reinforcing rods or other metallic



materials shall be placed around the conduits, either individually or in groups, in such a manner as to form a magnetic loop.

d. Enclose ducts in a minimum 75 mm concrete envelope. Concrete mix shall be to the Company approval.

e. Reinforce the concrete envelope at all points where ducts cross fill or loose soil, water, gas or sewage mains, under roadways and siFEWAlks, or elsewhere shown on the Drawings. Provide one 20 mm reinforcing rod between each two ducts of bottom layer, and one rod laid at each lower corner of duct envelope. Lay rods parallel to ducts, centered between ducts and placed halfway between bottom of ducts and bottom of concrete envelope. Extend reinforcing a minimum of 1500 mm beyond each side of fill or pipe main, and where spliced, provide a lap of 20 diameters. Consult with the Engineer, after the trench is excavated, to determine locations requiring reinforcing.

f. Hand "vibrate" concrete to provide complete encasement of all conduits.

g. After the duct line has been completed, a standard flexible mandrel not less than 300 mm long, having a diameter approximately 5 mm less than the inside diameter of the conduit, shall be pulled through each conduit, after which a brush with stiff bristles shall be pulled through each conduit to make certain that no particles of earth, sand, or gravel have been left in the line. Pneumatic rodding may be used to draw in the lead wire. A galvanized-iron pull wire free of kinks and splices shall be installed in all unused ducts and shall extend a minimum of three feet into each manhole.

h. All conduits or ducts, active or spares, entering a building shall be completely and adequately sealed at first termination with suitable plastic expansible compound to prevent the entrance into the building of rodents, gases, or vapors.

19. Outlet Boxes and Pull Boxes.

a. Rigidly mount all boxes and provide with suitable screw fastened

covers. Plug open knockouts or holes in boxes with suitable blanking devices.

b. Install pull boxes in locations that will be accessible after completion

of the building. Provide pull boxes or junction boxes to limit conduit runs to 20 m and to limit angles to the equivalent of 180 degrees. Additional pull boxes may be provided to facilitate wire pulling.

3.03 SCHEDULES

A. Outlet Boxes, Pull Boxes, and Conduit Fittings. Provide galvanized steel outlet boxes with leveling lugs and conduit knockouts (complete with brass earth terminal) pull boxes, and conduit fittings.



1. Where space is limited, shallow boxes may be used for switch, and telephone outlets with specific approval only. Provide cast cover and neoprene gaskets for weatherproof or exterior boxes. Provide extension and plaster rings as required. Size outlet boxes in accordance with the allowable fill permitted by the code.

2. Pull Boxes. Provide code gage galvanized sheet metal sized as per the code

or as shown on the drawings. Provide removable cover on the largest access side of the box unless otherwise detailed. Where cast boxes are specified, provide conduit entrances with threaded hubs. Provide stainless steel screws in all exterior locations and in wet or damp locations. Exterior boxes other than the cast type shall be raintight and gasketed.

3. Conduit Fittings.

All conduit fittings shall be of similar material and finish to the particular conduit being used and shall be of the same manufacturer.

Elbows and tees, inspection or solid types are not normally allowed, but where conditions warrant the use of these fittings, the Contractor shall apply to the Company for permission to use such accessories.

Standard circular boxes (Class B) to BS 31 to BS4568 Part 2 (metric) small or large pattern as specified shall generally be used at lighting points.

Where with specified permission only, the conduit is run in the floor screed and the thickness of the floor screed and the thickness of the floor slab is so limited as to prohibit a 90 deg bend being obtained in the conduit, angle entry pattern looping-in boxes may be used.

Adaptable boxes shall be heavy gauge pattern and of ample size of the quantity of conduits that are to be accommodated.

Pressed steel adaptable boxes may be used at multiple intersection points, but cable from more than one distribution board shall not enter any one adaptable box.

Where inspection boxes occur in floor slabs, non-ferrous metal floor traps of a type approved by the Engineer shall be installed over the boxes, fixed in position by brass screws.

The aperture area of the traps shall be sufficient to enable the covers of the inspection boxes to be easily removed. Trap covers shall be recessed or plain type to suit particular floor finish.

All junctions shall be made at galvanised steel circular junction boxes. Standard boxes shall be used as point boxes for all points.

16110.pdf

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