CHARLIE MCCANN

• Jan 17th, 2007

 

Q.WHAT SIZE CABLE DO I REQUIRE FOR A 63 AMP SIGLE PHASE CIRCUT WITH A RUN OF 290 MTS UNDERGROUND MANY THANKS

soumendasbiswas

 Profile Answers by soumendasbiswas 

• Jul 6th, 2009

 

Full load current for 100Kw is near about 175A.
Let derating factor 0.65 then current is 270 Amp.
We can use 3.5core 150 sq mm XLPE Cable.
Now, Voltage drop for 200meter or 0.2Km for 150sq mm is (0.48X0.2X270)=25.92v/km/amps, which is more than 10% so in this case we have to take 185sq mm XLPE Cable.
We have to maintain voltage drop in between 5%, so the cable size will be 3.5CX185 Sq mm XLPE Cable.

mustafa_musvi

 Profile Answers by mustafa_musvi 

• Oct 20th, 2009

 

Mr Biswas please specify
Below is the case you mentioned regarding cable losses
I have 2 questions request for your answer

1 The (0.48) is it resistivity of conductor ? or any other value

2
You have mentioned XLPE cable which is 11KV rated ? where as we have 100KW 3Phase Induction motor LT in this case the equation will be same or changed ?

Full load current for 100Kw is near about 175A. Let derating factor 0.65 then current is 270 Amp. We can use 3.5core 150 sq mm XLPE Cable. Now, Voltage drop for 200meter or 0.2Km for 150sq mm is (0.48X0.2X270)=25.92v/km/amps, which is more than 10% so in this case we have to take 185sq mm XLPE Cable. We have to maintain voltage drop in between 5%, so the cable size will be 3.5CX185 Sq mm XLPE Cable.

Mustafa Ali

soumendasbiswas

 Profile Answers by soumendasbiswas 

• Oct 21st, 2009

 

1.The (0.48) is it resistivity of conductor ? or any other value

 Well here 0.48 is the estimated voltage drop in XLPE cable.(You can get this value from any cable manufacture catalogue)

2.You have mentioned XLPE cable which is 11KV rated ? where as we have 100KW 3Phase Induction motor LT in this case the equation will be same or changed ?

 Here XLPE cable is 1.1kV rated.