Answer / thowsif_emerson_csm team

Cable size is dependent upon the load(s) you wish to supply
power too. You have to know the maximum current you can be
expected to carry on a particular circuit BEFORE choosing a
cable.

Once you know the load, you need to choose a cable size
rated to carry at least that much current, preferably more
as a safety factor.

So if you are planning on running several electrical
devices with a combined current of 20 amps, you need a
cable sized to carry at least 20 amps, and slightly more.

To calculate the size of a power cable,pls refer the
following table LINK:-

http://www.electrician2.com/calculators/wireocpd_ver_1.html

Answer / sr

The factors involved in cable sizing are:
1. Voltage grade
2. Various Derating factors depending on cable laying
(direct in ground), ambient temperature considered, group
factors (all these data are available in cable catalogue)
3. Length of cable laying for calculating voltage drop.
Voltage drop shall generally be within a max. of 3%.

Answer / anand

Size of LT able depend upon
1. Load that cable is to carry. Generally, design load for
cable selection is appx 1.4-1.5 times theoretical load
2.Voltage drop while carrying current. Higher the size of
cable, lesser is voltage drop.

Size of HT cable is decided on the basis of load as well as
fault current it is supposed to carry during fault. Cable
hould be able to carry fault current till the tripping
circuits trips

Answer / rajeev

Hi Thowsif,


Gud Answer Yar..

Thanks a lot...

Answer / ahmed omer

to calculate the size of cable you have to follow the
following:-
FOR FEEDER
1- load rating
2- voltage rating
3- determine the full load current(IFL)
4- total deration factor to be found
5- determine the cable current carrying capacity=IFL/total
deration factor
6- above value to be comprise with the valu of current
carring capacity in the table of factory

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