raceways

ELECTRICAL RACEWAYS 16140 - 1

SECTION 16140

ELECTRICAL RACEWAYS

PART 1 GENERAL

1.01 SECTION INCLUDES

A. Electrical Raceways and accessories including, but not limited to, the following:

1. PVC Conduits.

2. Electrical Metallic Tubing (EMT).

3. Rigid Steel Conduits.

4. Flexible Conduits.

5. Surface/Floor Cable Trunking.

6. Cable Trays.

7. Cables Ladders

8. Three Compartment Trunking.

1.02 RELATED SECTIONS

A. Section 01039 Coordination and Meetings.

B. Section 01300 Submittals.

C. Section 01600 Materials and Equipment.

D. Section 01740 Warranties.

E. Section 16010 Basic Electrical Requirements.

F. Section 16030 Electrical Identification.

G. Section 16110 MV Cables and Accessories.

H. Section 16120 LV Cables and Wires.

I. Section 16150 Electrical Boxes and Fittings.

J. Section 16160 Equipment Connections and Supports.

K. Section 16180 Underground Electrical Services.

1.03 REFERENCES

A. NFPA 70 NEC Chapter 3; Wiring Methods and Materials.

B. ANSI C 80.1-83 Rigid Steel Conduits, Zinc Coated.


C. ANSI C 80.3-83 Electrical Metallic Tubing, Zinc Coated.

1.03 SUBMITTALS

A. Comply with Section 01300.

B. Submit manufacturer's data on all types of electrical raceways, together with samples of the

proposed materials.

1.04 QUALITY ASSURANCE

A. Manufacturers: Firms regularly engaged in manufacture of raceways of types and ratings

required, whose products have been in satisfactory use in similar service for not less than 10

years. Preference shall be given to local manufacturers and agents/suppliers.

B. Installer: Firms regularly engaged and qualified with at least 5 years of successful installation

experience on projects with electrical installation work similar to that required for the project.

C. Electrical Raceways shall generally be manufacturer’s standard construction and materials.

Where this contradicts any part of the Specifications, the Contractor shall state so at the

time of tender.

1.05 DELIVERY, STORAGE AND HANDLING


B. Provide colour-coded thread protectors on the exposed threads of metal conduit, handle

raceways carefully to prevent end-damage and avoid scoring the finishes.

C. Where possible the raceways shall be stored indoors. If necessary to store outdoors, the

raceways shall be elevated well above ground and enclosed with durable waterproof

wrapping.

1.06 WARRANTY


PART 2 PRODUCTS

2.01 PVC CONDUITS

A. All PVC conduits and fittings shall be uPVC heavy gauge, rigid, direct buried or encased

buried type as applicable, complying with BS 6099-2.2 / IEC 614-2-2 heavy gauge in all

respects, and may be used where ambient temperatures do not exceed 75 oC.

B. All PVC conduits and accessories shall be obtained from the same manufacturer.

C. No conduit shall be less than 20 mm diameter.

D. Fittings and accessories for PVC conduits shall include, but not be limited to, the adapters,

junction/pull boxes, bushings, couplings, elbows, nipples, plugs, seals, etc.


E. Conduit boxes shall be of the circular pattern with appropriate spout entries and 50.8 mm

accessory fixing centres.

F. All connections and terminations of the PVC conduits and fittings shall be by means of the

manufacturer's standard adaptor.

G. All boxes shall have brass thread inserts for the fixing of accessories or covers.

H. All tees shall be made using conduit tee boxes. Tangential entry boxes shall be used where

appropriate. Multiple conduits may necessitate the use of large uPVC adaptable boxes for

junctions.

I. All saddles shall be of the spacer bar type and from the same manufacturer as that of the

conduit which they are being used to secure.

J. All wall mounted accessory boxes shall have one adjustable fixing lug to facilitate final

leveling of accessories.

2.02 ELECTRICAL METALLIC TUBING (EMT)

A. All Electrical Metallic Tubings (EMT) and accessories shall conform to NEC article 348

Part-B and ANSI C 80.3; not less than 20 mm (¾”) diameter.

B. All EMT and accessories shall be completely free from rust or other defects and shall have

same finish throughout the installation.

C. Fittings and accessories for EMT shall include, but not be limited to, adapters, junction/pull

boxes, bushings, connectors, couplings, elbows, expansion joints, gaskets, hubs, locknuts,

nipples, plugs, seals, etc.

D. The fittings and accessories for EMT shall be compression type. Pot metal or die-cast type

and "sock-on” or “drive-on” type fittings shall not be used.

E. Only standard manufactured fittings and accessories for EMT shall be used. Adaptation

between EMT and PVC or RSC shall be through metal boxes.

F. All saddles for surface mounted installation of EMT shall be of the space-bar type and of

the same finish as that of the EMT, which they are being used to secure.

G. All necessary boxes shall have one adjustable fixing lug to facilitate final levelling of

accessory.

2.03 RIGID STEEL CONDUITS (RSC)

A. All Rigid Steel Conduits (RSC) and accessories shall be heavy gauge welded steel

complying with NEC article 346, not less than 20 mm diameter.

B. RSC and fittings shall be hot dipped galvanized, complying with ANSI C 80.1, providing

heavy protection both inside and outside. The steel shall be galvanized after cutting and

threading.

C. All conduits and fittings shall be threaded, free from rust or other defects and shall have

same hot dipped galvanized finish throughout the installation.


D. Fittings and accessories for RSC shall include, but not be limited to, adapters, junction/pull

boxes, bushings, connectors, couplings, elbows, expansion joints, gaskets, hubs, locknuts,

nipples, plugs, seals, breathers, etc.

E. Fittings and accessories for RSC shall be of malleable iron or a mixture of grey iron and

cast steel.

F. All bushes shall be hexagonal headed, heavy duty, long threaded brass bushes complete

with serrated tempered shakeproof washers. All bends shall be cold set. All tees shall be

made using circular tee conduit boxes.

G. All saddles for surface mounted installation of RSC shall be of the spacer bar type and of

the same finish as that of the conduit which they are being used to secure.

H. A tapped earth connection facility shall be provided in every box.

I. All accessory boxes shall have one adjustable fixing lug to facilitate final levelling of

accessory.

J. PVC coated RSC and fittings shall be used for cables extending to outside of building and

where above grade extensions of PVC Conduits required a transition from PVC to RSC.

K. PVC coated rigid steel conduits and fittings shall conform to ANSI C 80.1, NEMA RN 1,

and shall be UL-listed for 90 0C conductors. The thickness of the PVC coating shall be a

minimum of 40 mil. A PVC jacketed coupling shall be provided with each length of

conduit. A PVC sleeve equal to the outside diameter of the conduit shall extend 37 mm

inches from each end of coupling. All fittings and accessories shall be provided with type

304 stainless steel hardware.

2.04 FLEXIBLE CONDUITS

A. Flexible conduits shall be liquid-tight, constructed from galvanized steel core and

continuous liquid-tight PVC jacket in accordance with NEC article 351 Part-A, not less

than 20 mm diameter.

B. Flexible conduit shall only to be used for final connection to items of fixed equipment

subject to vibration or movement.

C. All flexible conduits shall comply with UL1 and shall have a liquid-tight PVC jacket

capable of withstanding 90 oC cable operating temperatures.

D. All fittings and accessories for liquid-tight flexible steel conduits shall be nylon jacketed.

E. Nylon jacketed brass adaptors shall be provided for connection at either end of the flexible

conduit and should be of the compression type.

2.05 SURFACE/FLOOR CABLE TRUNKING

A. Surface/floor cable trunking shall be used with prior approval of the Engineer, wherever

possible to replace multiple conduit runs.

B. Metal surface/floor cable trunking shall comply with NEC and shall be manufactured from

galvanised steel sheets.


C. Only purpose made bends, tees, risers, end stops, fittings, connectors, covers and

accessories by the same manufacturer as the trunking shall be used and finished in hot

dipped galvanized steel. Site fabrication shall not be permitted.

D. Tinned copper earth straps shall be provided at every joint of the metal surface/floor

trunking.

E. Covers for surface type cable trunking, suspended for fixed on surface of wall or under

raised floor, shall be of the overlapping type and secured to the trunking by an approved

type of fastening arrangement such as clips, etc.

F. In outdoor locations and areas subject to corrosive atmospheres, all trunking shall be

painted with chlorinated rubber paint or PVC/Epoxy coating as approved by the Engineer.

G. Surface/Floor Cable trunking shall be single or multi-compartment as required. Where

multi-compartment is used, vertical dividers shall be provided between the compartments

which shall be welded to the trunking prior to galvanising.

H. Heavy Duty uPVC trunking with clip on lid (all insulated) shall be used, if shown on the

Drawings or specified elsewhere, to replace multiple conduit runs. All PVC cable trunking

and accessories shall be obtained from the same manufacturer. Only standard accessories

fabricated by the manufacturer shall be used and no site fabrication shall be allowed.

I. Floor trunking and covers shall be standard products of an approved manufacturer with

modular sections to provide flexibility of installation to suit any site situation. The floor

trunking and cover shall be suitable for surface or embedded installation as per actual site

requirements. The construction and dimensions of the floor trunking and cover for

embedded installation shall match with the floor finishing pattern having special provision

of accepting floor tiles, carpet, etc. within the recess of the cover provided in accordance

with the site requirements.

2.06 CABLE TRAYS

A. All cable trays shall be of heavy duty perforated type with return flange in non plenum

areas an non perforated type with cover in air plenum.

B. All cable trays shall be manufactured from hot-dip zinc coated galvanized steel, with a

standard heavy duty galvanizing coating of 350 g/m2 and Z2 bending grade.

C. All accessories and fittings such as bends, tees, elbows, cross units and angles shall be of

the same specification as that of the cable tray finish and shall be standard products from

the same manufacturer as the cable tray. Site fabrication shall not be permitted.

D. Cable trays and accessories shall be of a thickness of not less than:

1. 1.5 mm up to 305 mm width.

2. 2.0 mm above 305 mm width.

E. All fixing brackets, nuts and bolts shall be finished by hot dip galvanising.

F. Tinned copper earth continuity straps shall be provided at every joint of the cable tray.

G. Where cable tray crosses building expansion joints, the tray shall be installed suitably to

provide expansion / contraction with the building expansion.


H. Where cable tray carries 13.8 kV cable, a tray lid shall be installed.

I. In outdoor locations and areas subject to corrosive atmospheres, all cable trays shall be

painted with chlorinated rubber paint or PVC/Epoxy coating, as approved by the Engineer.

2.07 CABLE LADDERS

A. All cable ladders shall be heavy duty gauge (>2 mm), manufactured from hot-dip

galvanized steel with a standard heavy duty galvanizing coating of 350 g/m2 and Z2

bending grade.

B. All accessories and fittings such as couplers, bends, tees, elbows, etc. shall be by the same

manufacturer as the ladder.

C. Ladder system supports shall be determined in accordance with the manufacturer's

structural information to ensure that undue stress or bending shall not occur.

D. Tinned copper earth straps shall be provided at every joint of cable ladders.

E. In outdoor locations and areas subject to corrosive atmosphere, the ladders shall be painted

with chlorinated rubber paint or PVC/Epoxy coating, as approved by the Engineer.

2.08 THREE COMPARTMET TRUNKING

A. The trunking shall be made of extruded uPVC and shall have 3 compartments within its

profile with provision for an interlocking extension trunking compartment. The central

compartment shall carry power cables and shall be in a position to accommodate boxes to

mount wiring accessories. The dimensions of the system shall be 170x 50 mm.

B. The system shall be modular to the extent that covers and bases are supplied separately

The trunking shall be such that all electrical energy requirements can be satisfactorily

contained and visually coordinated with the system, it should also allow heavy

concentration and mixture of outlets possibly requiring changes to their location at a later

date. The system must have all accessories either mains of ELV positioned adjacent to one

another.

C. The system shall have a comprehensive range of couplers, end plates, inside and outside

corners, both horizontal and vertical. The Accessories shall have a finish compatible to the

main trunking.

There shall be complementary range of flat angles and Tees to allow the trunking to follow

its profile along the vertical face.

D. The system must be fabricated from non-flame propagating materials in accordance with

BS 6099 and BS 4678 part 4. The extruded products shall have a class 1Y rating, while the

moulded material shall conform to IEC 695 – 2 –1.

E. The trunking system must be non corrosive and not affected by seawater and should be

resistant to mineral acid, alkalis and detergents.


PART 3 EXECUTION

3.01 INSPECTION


B. All Electrical Raceways including conduits and fittings shall be free from objectionable

lines, striations, bubbles, welds, and other manufacturing defects that would impair the

service of the raceways. The bore of the conduits shall be circular in cross-section with

smooth interior surfaces free from rough and flaky areas. The electrical raceways and

fittings shall be free from all substances that injuriously effect any wire or cable covering.

C. All the Electrical Raceways including conduit runs are shown diagrammatically on the

Drawings to outline the general routing only. Any interference with pipes, HVAC ducts,

structural members or other equipment shall be inspected and coordinated well before

commencement of the installation of raceways. Deviations shall be made in accordance

with the approval of the Engineer, at no extra cost to the Contract.

3.02 PVC CONDUITS INSTALLATION

A. PVC conduits shall be used only where cast into slabs, built or chased into walls etc. Where

conduits are surface run in ceiling voids, shaft spaces, plant rooms etc. galvanised RSC or

EMT shall be used. Adaptation between PVC and metal conduits shall be through metal

boxes.

B. PVC conduits shall not be installed in locations exposed to direct sun light.

C. Where conduit boxes are not to be fitted with accessories, they shall be fitted with cover

plates which shall be overlapping where flush boxes are used.

D. PVC conduits shall be jointed and terminated utilising the following appropriate

components as supplied by the conduit manufacturer:

1. Purpose made adaptors and accessories.

2. Permanent adhesive - Solvent cement to produce a rigid watertight joint when used

with standard couplers and accessories.

3. Flexible adhesive - A non-hardening adhesive to be used where expansion facilities

are required in long conduit runs, in conjunction with expansion coupler. Not to be

used at building movement joints.

E. PVC conduits up to 25 mm diameter may be bent cold with the use of the appropriate

bending spring obtained from the conduit manufacturer. For larger size conduits, it is

necessary to use heat or appropriate manufacturer's standard ready made bends.

F. Adequate allowance shall be made for linear expansion and contraction of the conduits

under normal working temperature variations, as follows:

1. Expansion couplers shall be used on all straight runs of conduit exceeding 6 m in

length.

2. Conduit shall be free to slide within saddles.

3. Allowance for expansion in cast in-situ installation is normally only required to effect


structural movement at building expansion joints.

G. Conduit shall be supported at intervals of 1.5 m in isolated positions or 1 m in accessible

situations. Where working temperatures are high, this spacing shall be reduced accordingly.

H. Multiple conduits may necessitate the use of large PVC adaptable boxes for junctions,

which shall be readily accessible at all times.

I. Care shall be taken in the support of totally enclosed lighting fittings. Where excessive

temperatures are likely to occur, special heat resistant boxes shall be used, i.e. of a pattern

specifically designed to improve weight loading characteristics at high temperatures.

J. Spacing/fill factors shall be applied to all conduits in accordance with NEC Chapter 9,

Table-1.

K. Do not install PVC conduits closer than 75 mm to pipes of other services.

L. "Draw-in" boxes shall be installed in all conduit runs exceeding 3 m in length at a

maximum 12 m spacing and shall be readily accessible at all times.

M. Inspection elbows, bends or tees shall not be permitted for flush installation.

N. Use extension rings where boxes are found to be not flush with the finished surface. Care

shall be taken to prevent water, dirt, dust or debris from entering the conduit system.

O. All bends shall be made so that the PVC conduits shall not be damaged, and the internal

diameter of the conduits shall not be effectively reduced.

P. Not more than four 90 degree bends nor a total of 360 degree bends shall be made in one

conduit run between outlets, fittings or outlet bodies including any bends located

immediately at the start or end.

Q. Install concealed conduits such that only two crossings at a given point are allowed within

the slab to prevent any damage or cracking of slab.

R. No conduit shall be allowed to run in the floor screed of toilets, kitchen, bathroom or any

other wet area.

S. Where cables pass through ducts or sleeves entering buildings, seal the ends of the ducts or

sleeves using a special caulking compound of a putty-like consistency. It shall be workable

with the hands at temperatures as low as 1.7 oC, and shall not slump upto a temperature of

149 oC or less. It shall not be hardened materially when exposed to air.

3.03 METAL CONDUIT INSTALLATION

A. Metal conduits either Rigid Steel Conduits (RSC) or Electrical Metallic Tubings (EMT)

shall be installed in exposed locations as required.

B. EMT shall be used inside buildings, generally above suspended ceiling, with the exceptions

of below grade within the building structure or external underground or at exposed

locations liable to be damaged mechanically. RCS shall be installed exposed on surface at

all such locations where conduits are liable to be damaged mechanically.


C. Threads for RSCs shall be of sufficient length to allow conduits to butt together within

couplers. A minimum engagement of five (5) full threads shall be made at all fittings and

accessories.

D. Remove oil and grease from all threads of RSCs.

E. Support all metal conduits at intervals of 1.5 m in isolated positions or 1 m in accessible

situations.

F. Do not install metal conduit closer than 75 mm to pipes of other services.

G. All conduit boxes not to be fitted with accessories shall have metal cover plates which shall

be overlapping where flush boxes are used.

H. 'Draw in' boxes shall be provided in conduit runs exceeding 3 m in length. 'Draw in' boxes

shall be at a maximum 12 m spacing and readily accessible at all times. Adaptable junction

boxes shall also be accessible at all times for inspection and maintenance.

I. Exercise care shall be taken to prevent water, dirt and debris from entering the conduit

system.

J. Use extension rings where boxes are found not to be flush with the finished surface.

K. Protect conduits and conduit accessories from rust and mechanical damage. Exposed

conduit threads and damaged or rusty portion of metal conduits shall be painted, using an

oxide undercoat and aluminium paint, after being cleaned to bare metal.

L. Conduits installed in areas subject to corrosive atmospheres shall be painted with

chlorinated rubber paint after the installation is complete.

M. Under no circumstances, shall any metal conduit be used as a circuit protective conductor

(CPC). Every final sub-circuit shall incorporate its own separate Cu/PVC CPC.

N. Apply spacing/fill factors to all metal conduits in accordance with NEC Chapter 9, Table-1.

O. Field bends shall be made with a hand bender for 1-1/2” (38mm) and smaller diameter

metal conduits only. Larger size conduits shall be bent with a machine bender or be factory

supplied. Heating of metal conduits to facilitate bending is not permitted.

P. All bends shall be made so that metal conduits shall not be damaged, and the internal

diameter of the conduit shall not be effectively reduced. The inner edge radius of all field

bends shall not be less than the minimum allowable radius as per NEC.

Q. Not more than four 90 degree bends nor a total of 360 degree bends shall be made in one

conduit run between outlets, fittings or outlet bodies including any bends located

immediately at the start or end.

R. Conduits and elbow used for cables extending to outside of building shall be PVC coated

rigid steel extending one meter from building foundation. A concrete encased PVC adapter

shall be used in case cable extending will run in PVC ducts. Bells shall be provided on PVC

horizontal stub outs.

S. PVC conduits shall not be extended above grade. Where extensions of PVC conduits above

grade are required, a PVC coated rigid steel transition bend having PVC/steel coupling on

one end and threaded male or female adaptor on the other end. The PVC coated rigid steel


transition bend or conduit shall extend minimum 150 mm above grade. A concrete envelope

100 mm high shall be formed around such risers to minimize corrosion at point of

emergence. The top of the envelope shall be sloped for drainage.

T. Verify exact stub up location and termination requirement for items and equipment being

served, for all necessary power and control wiring.

U. Where cables pass through ducts or sleeves entering buildings, seal the ends of the ducts or

sleeves using a special caulking compound of a putty-like consistency. It shall be workable

with the hands at temperatures as low as 1.7 oC, and shall not slump upto a temperature of

149 oC or less. It shall not be hardened materially when exposed to air.

V. Where conduits turn out of, or penetrate, a slab, they shall be not less than 65 mm on

centers.

W. Location and sizing of conduit sleeves passing through floors and walls that are not shown

on the Drawings shall be the responsibility of the Contractor. All sleeves shall be rigid

galvanized steel unless indicated otherwise, extended 150 mm above floor and capped when

not in use. Space between conduits and sleeves shall be filled with ductseal to a minimum

of 50 mm deep at top and bottom of conduit sleeve.

X. All metal conduits entering any gasketed boxes or gasketed equipment enclosure shall be

provided and terminated with gasketed hubs with bonding screws. Whereas the metal

conduits entering non-gasketed sheet-metal boxes or enclosures shall be provided and

terminated with general purpose hubs.

Y. Provide supports to alleviate stress on cables where they enter a conduit or other enclosure

from the tray.

3.04 FLEXIBLE CONDUITS INSTALLATION

A. All flexible conduits and fittings used shall be liquid-tight.

B. Flexible conduits shall only be used in short lengths, of less than 1000 mm, in cases

where a final connection is required to be made to a fixed item of equipment which is

subject to vibration or thermal expansion.

C. Flexible conduits shall be 1.25 x L in length, L being the direct distance between

connection unit and fixed appliance, up to maximum length of 1 m.

D. Purpose made glands shall be used on the ends of all lengths of flexible conduits.

E. A separate Cu/PVC circuit protective conductor shall be included in all lengths of flexible

conduits.

F. Flexible conduits shall be installed so as not to incur undue mechanical strain, damage or

excessive temperatures.

3.05 SURFACE/FLOOR CABLE TRUNKING INSTALLATION

A. Cable trunking shall be fixed securely to the building structure at intervals not exceeding

1.5 m.

B. Where vertical runs of trunking exceed 3 m in length, pin racks shall be fitted.


C. Spacing/fill factors shall be applied to all cable trunking in accordance with NEC

requirements.

D. For metal trunking installations, earth continuity shall be ensured by means of tinned

copper earth straps bolted across each joint. Flexible braided straps shall be used for

expansion joints.

E. Metal trunking cut during installation shall have the cut ends painted with an oxide

undercoat and an aluminium top coat.

F. Where metal trunking is installed in areas subject to corrosive atmospheres, the complete

trunking installation shall be painted with a chlorinated rubber paint after the installation is

complete.

G. Expansion joints with gaps shall be incorporated in all cable trunking runs in excess of 6 m

in length. External couplings shall have elongated slots and fixing holes shall be drilled

oversize to give freedom of linear movement. Internal couplings shall be securely fixed at

one end by use of thixotrophic adhesive leaving the other end free for linear movement.

H. Bare copper or aluminium cables shall not be run in metal trunking.

3.06 CABLE TRAYS/LADDERS INSTALLATION

A. Where practical, cable trays/ladders shall be run horizontally and flat or vertically and shall

be supported at distances not exceeding 1.5 m to the building structure using mild steel

brackets. These brackets shall be secured to the building structure using expanded bolts and

washers or built into the building structures during construction.

B. Where cable tray/ladder is suspended, 2 drop rods shall be used at each suspension point to

an angle iron or channel support to which the cable ladder is bolted. The spacing of

suspension points shall be determined in accordance with the manufacturer's structural

information such that undue stress of defection does not occur.

C. Where cable tray/ladder is cut, the open ends shall be painted using an oxide undercoat and

an aluminum top coat. Where the finish is PVC, a top coat of liquid PVC solution shall be

applied after the completion of the cable ladder installation.

D. Cable trays/ladders run parallel with walls shall not be mounted closer than 75 mm to the

wall.

E. Secure all cables to cable trays/ladders at distances in accordance with NEC requirements

F. Do not run bare copper or aluminum cables run on cable tray/ladder.

G. Ensure earth continuity by means of tinned copper earth straps bolted across each cable

tray/ladder joint. Flexible braided straps shall be used for expansion joints.

3.07 DADO TRUNKING INSTALLATION

Trunking shall be laid in straight lines between each 3 mtr lengths along with the necessary

trunking couplers, and changes in direction to be made with the help of Inside/Outside


corners as per manufacturer recommendations.

All joints between trunking and the accessories along with the service outlets shall be properly

secured to prevent loosening.

All accessories are hard wired to respective positions as shown in the installation guide to

ensure a clean and neat hand over.

END OF SECTION 16140

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