How to create cable schedule for a project

Posted on Posted in Electrical, Study Material

Hi reader,

Wondering how to create cable schedule for approval of your project? It is easy.

  1. Do you have the SLD (single line diagram of HT/ LT Side)
  2. Do you have the equipment layout drawings, ask the consultant to provide.
  3. Do you have the Cable tray drawing, please get a cable tray drawing.

This much information is good enough to get the job done.

First of all make an excel using SLD and the equipment drawing

Source Location Destination Location Cable Type Grade Length

Ex :

S.No Source Location Destination Location Cable Type Grade Length
1 SEB NA HT Panel Substation 3C X 300 XLPE 30.0
2 HT Panel Substation Transformer Substation 3C X 300 XLPE 21.5

Now the cable size is already given in SLD which 3C 300 sq mm HT Cable. We have to see if the cable size is okay and have to calculate the voltage drop in the cable.

To know if the cable size is okay, you have to calculate the load current of the system.

Load current I = P(kW)/1.732/line to line voltage/PF X 1000

Current carrying capacity of the cable = you will get this from the catalog of your cable supplier.

If Load current < Current carrying capacity then it is okay otherwise propose a bigger size of the cable in your schedule.

Now calculate the voltage drop for each cable.

 V Drop    = √3 x I x Z x Length / (1000)

where Impedance (Z)= (R² + X²)^0.5

You will get the R and X from your supplier’s catalog.

Now ask the consultant for permissible voltage drop or make another column with main sheet showing the voltage drop of cables, along with the cable schedule.

Hope, everything was easy. If you need more info, you can write @pratham6138@gmail.com we will provide you an excel file for example.

Thanks for reading, please come back for other electrical related posts.

BD

 

 

One thought on “How to create cable schedule for a project

  1. Sir, Kindly tell me the formula for measuring of cable size for 11 kV. e.g: length = 150 ft , V=11000 v, Ampere = 662 per phase .

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