Answer for me

Here is another one .This has been discussed so many times Satish.Pl refer to earlier threads on the subject

to select an appropriate conductor

the following are to be established

1. the conductor material to be use eg. copper or aluminium
2. the total length of the line.
3. the type of installation eg directly mounted or underground etc.
4. the group of conductors that are close to the line.
5. the manufacturers data sheets.

from the total power at the receiving end of the line, the current can be calculated.

conductor selection

the data sheets have the maximum permissible current capacity of the cables in one of the columns.

select a cable (conductor) size that is slightly higher than that you require.

voltage drop

the next step would be to establish if the conductor selection you made allows the receiving end voltage to be within the desired 95 % (please check what the maximum permissible volt drop is, this differers in different localities)

the data sheets would have a section that specifies for all cable sizes, the mV/A/m which is essentially the voltage drop that would be expected for the applied current flow through the cable

using this value, the volt drop at the receiving can be calculated as follows.

introduce the length and the current as shown below.

total volt drop dV=from tables,volt drop(mV/A/m) X 1000 x current(A) x length(m)

the volt drop calculated above should be lower than the local by laws permissible level (eg.,< 5%)

if the volt drop is higher then use the next size up on the table and repeat you will find simple after a few attempts

remember that the manufacturers tables also specify de rate factors that apply if the cable is to be in close proximity to other and if direct exposure to solar radiation etc.

if motor loads are to be catered for then establish the type os srarting mechanisims to be used then, evaluate depending on motor current not kva, ensure that you cater for inrush current if soft starters are not used.

best of luck