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How to design a cable tray explain with one example?

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Question ajoutée par mohammed ASIF , Facility Engineer , Mosanada FMS
Date de publication: 2016/03/14

depends upon different parameter>>>

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

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

Rian Gualiza
par Rian Gualiza , Electrical Engineer/ Maintenance Supervisor , Seder Group

The question is too vague but I could give you some ideas on how to design a cable tray. You must determine the the numbers and size of cables that will pass to that particular tray for you to determine dimensions of cable tray you are going to use.

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