would someone mind checking my work?

[chadgaylord208]

i am a 1st year apprentice and would appreciate it if someone could check my work. Thank you in advance! #1 A single-phase load is located 2800 ft from its source. The load draws a current of 86 A and operates on 480 V. The maximum voltage drop at the load cannot be greater than 3%. What size aluminum conductors should be installed to operate the load? My instructor said to use a K factor of 21.2. I came up with 354511.1121, or 400kcmils. #2 It is decided to use parallel 0000 conductors to supply the load. How many will be needed? I came up with 2. #3 A three-phase motor operates on 480 V and is located 1800 ft from the power source. The starting current is 235 A. What size copper conductors will be needed to supply this load if the voltage must not be permitted to drop below 6% of the terminal voltage during starting? My instructor said to use a K factor of 12.9. I got 328159.8763, or 350kcmils. Thank you again for your help! It is really appreciated! -Chad

 

[Dennis Alwon]

First off I would check my calculation. I come up with 750mcm.

 

[chadgaylord208]

come again?

come again?

First off I would check my calculation. I come up with 750mcm.

for which question?

 

[Dennis Alwon]

for which question?

Part 1--- I used the online calculator and it is pretty accurate--

You can use it but use it to check your answer to see where you went wrong.

http://www.elec-toolbox.com/calculators/voltdrop.htm

 

[Oakey]

Dennis, thanks for the link. I didn't know about the online calculator. Very helpful

 

[Dennis Alwon]

Dennis, thanks for the link. I didn't know about the online calculator. Very helpful

Your welcome.

 

[nyerinfl]

I came up with 709022 cmil for the first questions, I agree with Dennis 750mcm - 2x21.2x86.2800 = 10209920 / 14.4 = 709022 cmil

 

[chadgaylord208]

different k factor

different k factor

my instructor changed the K factor so that we would have to work the questions out. but thank you for your answer and the link.