Calculation of Cable Tray Size


Calculate Size of Cable Tray for Following Cable Schedule. Cable Tray should be perforated and 20% spare Capacity. Distance between each Cable is 10mm. Cable are laying in Single Layer in Cable Tray.
(1) 2 No’s of 3.5Cx300 Sq.mm XLPE Cable having 59.7mm Outer Diameter and 5.9 Kg/Meter weight
(2) 2 No’s of 3.5Cx400 Sq.mm XLPE Cable having 68.6mm Outer Diameter and 6.1 Kg/Meter weight
(3) 3 No’s of 3.5Cx25 Sq.mm XLPE Cable having 25mm Outer Diameter and 0.5 Kg/Meter weight

Calculation:

Total Outer Diameter of all Cable Passing in to Cable Tray:

  • Diameter of 300Sq.mm Cable =No of Cable X Outer Diameter of Each Cable
  • Diameter of 300Sq.mm Cable =2X59.7 = 119.4 mm
  • Diameter of 400Sq.mm Cable =No of Cable X Outer Diameter of Each Cable
  • Diameter of 400Sq.mm Cable =2X68.6= 137.2 mm
  • Diameter of 25Sq.mm Cable =No of Cable X Outer Diameter of Each Cable
  • Diameter of 25Sq.mm Cable =3X28= 84 mm
  • Total Diameter of All Cables laying in Tray = (119.4+137.2+54)mm
  • Total Diameter of All Cables laying in Tray = 340.6mm

Total Weight of Cables Passing in to Cable Tray:

  • Weight of 300Sq.mm Cable =No of Cable X Weight of Each Cable
  • Weight of 300Sq.mm Cable =2X5.9= 11.8 Kg/Meter
  • Weight of 400Sq.mm Cable = No of Cable X Weight of Each Cable
  • Weight of 400Sq.mm Cable =2X6.1= 12.2 Kg/Meter
  • Weight of 25Sq.mm Cable = No of Cable X Weight of Each Cable
  • Weight of 25Sq.mm Cable =3X0.5= 1.5 Kg/Meter
  • Total Weight of All Cables laying in Tray = (11.8+12.2+1.5) Kg/Meter
  • Total Weight of All Cables laying in Tray =25.5 Kg/Meter

Total Width of all Cables:

  • Total Width of all Cables = (Total No of Cable X Distance between Each Cable) + Total Cable Outer Diameter
  • Total Width of all Cables = (7 X 10) + 340.6
  • Total Width of all Cables = 410.6 mm
  • Taking 20% Spare Capacity of Cable Tray
  • Final Width of all Cables = 1.2%X4106.6
  • Calculated Width of All Cables = 493 mm

Total Area of Cable:

  • Total Area of Cable = Final width of Cables X Maximum Height Cable
  • Total Area of Cable = 493 X 69.6 =28167 Sq.mm
  • Taking 20% Spare Capacity of Cable Tray
  • Final Area of all Cables = 1.2%X28167
  • Calculated Area of all Cable =33801 Sq.mm

CASE-(I):

  • Considering Single Run of Cable Tray having Size of 300X100mm, 120Kg/Meter Weight Capacity
  • Area of Cable Tray =Width of Cable Tray X Height of Cable Tray
  • Area of Cable Tray =300X100 = 30000 Sq.mm
  • Checking Width of Cable Tray
  • Calculated Width of Cable Tray as per Calculation=No of Layer of Cable X No of Cable Tray Run X Width of Cables
  • Width of Cable Tray as per Calculation=1X1X493 =493 mm
  • Checking Depth of Cable Tray
  • Actual depth of Cable Tray = No of Layer of Cable X Maximum Diameter of Cable
  • Actual depth of Cable Tray=1X68.6 =68.6mm
  • Checking Weight of Cable Tray
  • Actual Weight of Cables=25.5 Kg/Meter

Results:

  • Calculated Cable Tray width (493mm)> Actual Cable Tray width ( 300mm) = Faulty Selection
  • Calculated depth of Cable Tray (68.6mm)< Actual Depth of Cable Tray (100mm) = O.K
  • Calculated Weight of all Cables (25.5Kg/Mt) < Actual Weight of Cable Tray (125.5 Kg/Mt) =O.K
  • Required to select higher size Cable Tray due to small Cable Tray width.

CASE-(II):

  • Considering Single Run of Cable Tray having Size of 600X100mm, 120Kg/Meter Weight Capacity
  • Area of Cable Tray =Width of Cable Tray X Height of Cable Tray
  • Area of Cable Tray =600X100 = 60000 Sq.mm
  • Checking Width of Cable Tray
  • Width of Cable Tray as per Calculation=No of Layer of Cable X No of Cable Tray Run X Width of Cables
  • Width of Cable Tray as per Calculation=1X1X493 =493 mm
  • Checking Depth of Cable Tray
  • Actual depth of Cable Tray = No of Layer of Cable X Maximum Diameter of Cable
  • Actual depth of Cable Tray=1X68.6 =68.6mm
  • Checking Weight of Cable Tray
  • Actual Weight of Cables=25.5 Kg/Meter

Results:

  • Calculated Cable Tray width (493mm)< Actual Cable Tray width ( 600mm) = O.K
  • Calculated depth of Cable Tray (68.6mm)< Actual Depth of Cable Tray (100mm) = O.K
  • Calculated Weight of all Cables (25.5Kg/Mt) < Actual Weight of Cable Tray (125.5 Kg/Mt) =O.K
  • Remaining Cable Tray width Area =100%-(Calculated Cable tray width/ Actual Cable Tray Width)
  • Remaining Cable Tray width Area =100%-(493/600)% =17.9%
  • Remaining Cable Tray Area =100%-(Calculated Cable tray Area/ Actual Cable Tray Area)
  • Remaining Cable Tray Area =100%-(33801/60000) =43.7%
  • Selection of 600X100 Cable Tray is O.K

Conclusion

  • Size of Cable Tray= 600X100mm
  • Type of Cable Tray=Perforated
  • No of Cable Tray Run= 1No
  • No of layer of Cables in Cable Tray=1 Layer
  • Remaining Cable Tray width Area =17.9%
  • Remaining Cable Tray Area =43.7%
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Calculate Size of Cable Tray (Excel Sheet)


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  • Calculate Cable Tray width
  • Calculate Cable Tray area
  • Calculate Cable Tray length
  • Calculate Cable Tray Weight
  • Calculate Remaining width of Cable Tray
  • Calculate Remaining Area of Cable Tray

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