ssooria

 Profile Answers by ssooria 

• Dec 3rd, 2008

 

1) what is the load=      KW

2)from that calculate the actual current, I  =             KW
                                                                        -------------------
                                                                           1.732x 415x 0.8

3) voltage drop formula =  mv x I x l
                                         ------------------
                                            1000

mv-----Refer cable catologue,Related cable size apply that value

I------- Actual current, Amps from above formula

l--------- Length of the cable from source to destination (for example MDB to SMDB, SMDB to DB)

you can get Voltage drop of the selected cable.


Result:

The voltage drop value shuold be less than 2.5% or 4% depends upon local authority requiremend.

If the value exceded , go to the  next cable size.

repeat the same procedure.