DC voltage drop with length included..

[mta145]

Hoping that someone could help verify what i am getting...
Voltage is 420 DC
Load is 217 amps
Distance is 130'
Conductor is 300 mcm AL
I am coming up with 1% voltage drop is this correct?

420v DC
217 amps
Distance is 130'
Conductor is 3 sets of 2/0 AL
VD = .7%

Any help on this would be greatly appreciated

 

[RichB]

I get 2.4% for the first example and 2.7% for the second---but for some reason using the formula VD=2KLI/CM seems not exactly correct:?

K=12.9
L=130
I=217
CM= (First Ex) 300000 and 266200 for the second

 

[mivey]

300: At 85?F I get 0.807%

(3)2/0: At 85?F I get 0.605%

 

[mivey]

300: At 167?F I get 0.95%

(3)2/0: At 167?F I get 0.712%


300: At 77?F I get 0.793%

(3)2/0: At 77?F I get 0.594%

 

[Hv&Lv]

I get 2.4% for the first example and 2.7% for the second---but for some reason using the formula VD=2KLI/CM seems not exactly correct:?

K=12.9
L=130
I=217
CM= (First Ex) 300000 and 266200 for the second

K should be a direct current constant. Q would be an AC constant to be used when skin effect comes into play. Look at the difference in table 8 and table 9, in chapter 9 NEC.

 

[RichB]

K should be a direct current constant. Q would be an AC constant to be used when skin effect comes into play. Look at the difference in table 8 and table 9, in chapter 9 NEC.

AHA!!! I knew there was something tickling me that said I was incorrect!!!--Thanks Hv--That's what is so great about this forum, someone always has the answer and I (re)learn alot of stuff--especially as I am getting worse--that oldtimers disease, you know the one--CRS-- seems to be hitting more often (I know there is a reason but I can't remember where I read it) or at least the wife says so!~

Thanks guys!!