General Notes on Cable Trays

GENERAL GUIDELINES ON LAYING OF IMPULSE PIPE

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GENERAL NOTES ON CABLE TRAYS CABLE TRAYS : CABLE TRAYS ARE OF TWO TYPES 1.

Perforated Type in M.S. and Aluminum.

2.

Ladder Type Cable Trays are fabricated in three methods : a)

with Steel Sheets

b)

with Angles

c)

Aluminum Sheets

PERFORATED CABLE TRAYS : Perforated Cable Trays are fabricated out of Single Sheet Steel Confirming to I.S. 1079 : 1973 / I.S. 513 : 1994 in various thickness of 1.6mm, 2.0mm & 2.5mm. Perforated Cable Trays are available in standard widths of 50mm, 100mm, 150mm, 300mm, 450mm and 600mm and in standard Length of 2500mm. If other than the above mentioned widths are required the Trays are fabricated as per the specifications of Customers/Customer Consultants. TYPICAL SPECIFICATION OF PERFORATED CABLE TRAY (M.S. & ALUMINUM) 1.

Standard Length

:

2.5 Mtrs.

2.

Perforations

:

Slots 10mm x 20mm Width Wise : 10mm gap Length Wise : 20mm, 30mm, 40mmCC:

3.

Tray Width (W)

:

4.

Tray Height (H)

:

20mm – 25mm – 40mm – 50mm 75mm – 100mm (or any heights as per the requirement)

5.

Tray Collar (C)

:

15mm – 20mm – 25mm

6.

Tray Thickness (TH)

:

1.6mm – 200mm – 2.5mm – 3mm

7.

Types of Raw Material

:

Mild Steel – Aluminum

8.

Finish

:

50mm – 75mm – 100mm – 150mm - 200mm – 300mm – 450mm – 600mm (or any heights as per the requirement)

Hot Dip Galvanised – Electroplated – Powder Coated – Epoxy coated, Enamel Painted – Aluminum Painted.

Dividers and Covers are available as per the Drawings shown and the specs will be as per specs of perforated Cable Trays. ACCESSORIES Types of Bends : Horizontal, Vertical (Inside / Outside), Tees, (Equal & Un-equal), Crosses, Reducers Radius : 300 / 450 / 600 / 1000mm or as per the choice of customers Degrees : 30° - 45° - 60° - 90° for Bends.

http://www.bhelpswr.co.in/Technical/C&I/Erection/General%20notes%20on%20Cable... 1/22/2015


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LADDER TYPE Ladder type cable trays are fabricated out of steel sheets conforming to I.s. 1079 : 1973 & I.S. 513 : 1994 with a thickness of 1.6mm 2.0mm, 2.5mm and 3mm All cable trays are of standard lengths of 2500mm for various widths-minimum being 150mm wide and maximum 1200 wide. Slotted rungs are welded to the side runners at every 250mm or 300mm interval. At both the ends of the cable trays three or four circular holes are provided for connecting the adjacent cable trays or accessories/by coupler plates. ALUMINUM LADDER TYPE CABLE TRAYS Aluminum ladder type cable trays are fabricated out of aluminum sheets conforming to I.S. 737 : 1986 with thickness varying from 2mm, 2.5mm to 3mm. TYPICAL SPEC OF LADDER TYPE CABLE TRAYS (M.S. / ALUMINUM) 1.

Standard Length

:

2.5 mtrs

2.

Runner Height (H)

: 50mm – 60mm – 75mm – 100mm – 120mm

3.

Runner Collar (C)

:

4.

Rung Size (s)

: 25mm x 15mm / 35mm x 15mm / 40mm x 20mm 50mm x 20mm as per choice

5.

Thickness (TH)

6.

Welding (M.S.)

7.

Welding (Aluminum)

8.

Rung slot size

: 10mm x 20mm 10mm x 30mm – with spacing 10mm, 15mm or as per choice.

9

Rung spacing

:

10.

Finish

: For M.S. : Hot Dip Galvanised, Electroplated, Powder coated, Epoxy

15mm – 20mm – 25mm – 30mm

: : :

1.6mm – 2mm – 2.5mm – 3mm C-type Arc/welding C-type tig welding

250mm/300mm interval

painted, Enamel Painted Aluminum Painted 11.

Models

:

C-type, Z-type & L-type

All the slots and coupler holes on the trays are machine punched. LADDER TYPE WITH ANGLES Ladder type cable trays are fabricated of M.S. Angles conforming to I.S. 2062, 1992. M.S. angles are used as Runners and 25 x .6mm M.S. Flats as rungs. Rung spacing is 250mm for 2500mm length cable trays and 300mm for 3000mm lengths. Rungs can be provided single/double, as per the customers choice; Double rungs are provided with a cap of 10mm, for clamping the cables. TYPICAL SPECFICATION FOR ANGULAR LADDER TYPE CABLE TRAY 1.

Length (L)

:

2.5 mtrs/3mtrs

2.

Widths (W)

: 150mm – 300mm – 450mm – 600mm – 1000mm (or as per customers requirement)

3.

Runners (R)

:

50mm x 50mm x 6mm – 65mm x 65mm x 6mm



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4.

Rungs

:

25mm x 3mm – 25mm x 6mm – 32mm x 6mm

5.

Rung spacing

: 250mm, 300mm interval (double rung for bolting as per customers).

6.

Finish

: Hot dip galvanised, Painted ( colour as per choice), powder coated, epoxy painted.

CABLE TRAY SUPPORTS 1.

Type

:

Single, Double

2.

Tier

:

Available in 1-Tier to 6-Tier

3.

Center Support

:

Angle : 50mm x 50mm x 6mm Channel : 10mm x 50mm x 6mm

4.

Horizontal support

:

50mm x 50mm x 6mm or as per customers

5.

Finish

:

Hot dip galvanised or painted

6.

Accessories

:

Rawal plug, or expansion bolt for grounding

7.

Welding

:

Arc welding

8.

Slots (machine punched)

:

10mm x 15mm (or as per customers choice)

CABLE RACKS : These are used to support the cable trays at specified center distanced to lay the cable tray at different levels. The horizontal members which act as support to the cable trays, are fixed on it by means of bolts and nuts and are welded to the vertical member that is fixed to the wall by means of expansion bolts. These are generally fabricated out of structural steel (M.S. Angles) conforming to I.S. 2062 : 1992. While floating enquiry the following details are required. 1.

Perforated type/ladder type

2.

For perforated type the width, flange and collar.

3.

For ladder type, size of the runner i.e., the height, collar and also the rungs size, the height of the rung and width of the rung.

4.

Whether with cover

5.

Whether cover provision to be made to cable trays for future necessity.

6.

Gauge of cable trays

7.

Radius of accessories – i.e. 300, 450, 600

8.

Whether accessories required are 3 piece welded or in a semi-circular form delivery of welded accessories will be faster.

9.

Vertical bens whether up or down.

10.

Horizontal bends : Left/Right is common

11.

Reducers left or right

12.

Tees and crosses whether equal or unequal.

13.

Whether link plates are required or not. If required, the quantity to be specified. With or without bolts and nuts.



14.

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Delivery time.

FINISHING REQUIRED (AS PER COST PRIORITY) *

Epoxy coated – 50 microns (colours available – Grey, Black)

*

Powder coated – 50 microns (colours available, elegant to look at and good for indoor using)

*

Hot dip galvanising as per IS : 4759 and IS : 2629 (very useful for all outdoor and indoor uses and for coastal areas)

*

Electro plating – 15mic. Elegant looks – good for indoor use.

*

Enamel painted – all colours

*

Aluminium painted.

HOT DIP GALVANISING : The cable trays and accessories shall be hot dip galvanised after fabrication as per I.S. : 2629 : 1985 & I.S. 4759 : 1984. Amount of Zinc deposit for trays and coupler plates shall be maintained as per th I.S. Table mentioned below. COATING REQUIREMENTS : Mass of Zinc Coating – Requirement for the mass of zinc coating for different classes of materials are given below : Mass of Zinc Coating Sl. No. Microns

(4)

(1)

Product

(2)

Fabricated steel articles : a) 5mm thick and over b) Under 5mm, but not less than 2mm c) Under 2mm, but not less than 1.2mm

Minimum value of

In

Average of Mass of coatings (3) g/m2 610 460

86 64

Note 1 : The requirements for the minimum mass of coating are for normal or rural atmospheres. In case of special atmosphere like marine and industrial atmospheres, the minimum mass of coating shall be increased as agreed between the galvanizer and the purchaser. Note 2 : In case of fabricated steel structures, plates, etc, the coating mass is defined in terms of grams per square metre of the total surface area. The galvanising shall be uniform, clean, smooth, continuous and free from acid spots. Fasteners like screws, nuts and washers shall be electroplated. FIGURE – PAGE 165 FIGURE – PAGE 166 FIGURE – PAGE 167 FIGURE – PAGE 168



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FIGURE – PAGE 169 Back to C&I Index


General Notes on Cable Trays

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