Calculation of Cable Tray Size
December 7, 2014 47 Comments
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%
JIGNESH PARMAR
many thanks for your mail cable tray calculation it’s very useful, hope more cooperation in electrical design
regards Kamaran Aziz Ali
Hello Jignesh JI, I got your reference form one of your blog which describes safety measure for transformers. I am no expert and looking for buying my new home but there is a pad locked transformer next to property almost sharing the wall ( may be 2 feet distance). Looking at articles i am confused whether its safe to live next to transformer with 3 year old daughter. I would really thankful if you can share your formal advise? Many Thanks in advance. Mayank Tripathi
Very perfect information given regarding cable tray. Thanks
Thenks to discribe the knolged of cable tray
Kindly inform me how to calculate cable tray and calculacion of cable size
Sir,
May I know how to calculate cable tray size with double layer cable arrangement.
dear sir ,
nice information you are provide regarding all design basis .here i have doubt in cable tray size .. actually what is mean by single layer and double layer to be consider for cable tray size.
Thanks in Advance ,
P.M.Thiyagarajan.
thanks a lot for your amazing contribution
Dear sir how you got the height of the cable, From which catalog. Most of the catalog want give the information on height of the cables.
Dear sir very use full information…….by Deepan from Coimbatore
Dear sir,
I think there is a little mistake in calculation at ‘total area of cable’. Could you please correct the calculation. I am facing problem while practicing.
Thank you.
thank you
Dear sir,
Hope you are great,
And could you please tell me, That these calculations are based on which standards ?
Thank You
Dear Mr. Jignesh.Parmar
Thank you very much for sharing your knowledge with others . To be shorts I would like to have a specific notes on how to design power , control instrumentation cables and write their data sheets …etc..
please write to my mail as I’m in urgent need of these topic and ready to pay for it
Appreciate your quick reply
Engr. Amjad Q
Kuwait
SIr I would like to ask a question, why did you take a gap of 10 mm between cables why not 15 or 20mm ? Is there any standard of 10 mm?
Is there any ampacity or section restriction for cables on same tray
thats very good
Very useful information.Thanks.
Please send us the formula for calculating of making of cable tray in a 8 X 4 GI Sheet
Very Educative.
Thanks for sharing your knowledge with us. It helps me definetely
how to take cable tray weight of same 600×100 and 300×100
Dear Jignesh sir,Your articles are very useful for me,It’s easy to understanding.Thanking You sir
thank you sir for sharing this useful calculation between us.
easy for working
hi may i know how to calculate the cable SQMM to OD example you mentioned above 300sqmm cable od is 59.7 can you please describe
Please specify according to which international standard you calculated cable tray size?
is there anything to consider between choosing an 18×4 tray or a 12×6? the square inches would seem to be the same.
Dear sir,
Could you please tell me, That these calculations are based on which standards ?
Thank You
Hello sir the above formula is suitable for perforated type cable tray. So please provide details regarding selection of ladder type tray.
Dear sir,
Could you please tell me, That these calculations are based on which standards ?
Thank You
Hello sir,
Greetings of the day.
My question is how did you put the maximum height of cable i.e. 69.6.
Hello sir,
Greetings of the day.
May I know how to calculate cable tray size with double layer cable arrangement.
Can I get the Excel sheet of cable tray size calculation
Dear sir,
I tried so many times to search how much torque required for cable termination tightness but I fail to find any document in a simple language. So please help me in this matter.
My question is how much torque required for cable termination tightness in the bus bar / contractors / t.b./ any type of cable connection ?
SIR PLEASE CLEAR THE TOPIC VOLTAGE FLUCTUATION. MANY CONFUTION IN THIS TOPIC. PLEASE HELP ME HOW TO UNDERSTAND IN THIS TOPIC.
Hello,
How did you put the maximum height of cable i.e. 69.6?
how to calculate number of conductors in a cable tray?
How can I contact you please
HI, Could you tell me how to calculate of cables length (1.5mm, 2.5mm, 4mm, 6mm 10mm )in a building area of 15th floors?? thanks
Good Job … Thanks
Thanks for your sharing
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Hi this is a more important calculations
Hello sir, I am grateful for your useful information. I doubt on a total area of cable = total width X maxm height which is 493X 68.6 = 33819.8 but there is diff value why it is, how it came
How do you calculate the load bearing capacity of a cable tray (ladder/perforated)?
Hi Sir, Thank you very much for this informative article. Can you please advise why the area calculation is necessary ? If there is a restriction on number of layers (most cases yes 1 or 2 layers max), the usable area of the cable tray will be limited.