Very easy question on cable size calculation

[Randy holmes]

I am installing a new serve at my acerage and need to calculate the cable size from the power pole in the ditch to the service panel location. I will be using a 200 amp service panel. The power company is upgrading the xformer from 15 to 50 kva. The run is 310 feet total . My calculations show that I should be ok with less than 5% voltage drop using 2/0 copper wire for the 310 foot run but I will be buying aluminum as that is what is available here (Alberta Canada)

Can I use 2/0 or should I breakdown and go 4/0? aluminum

Thanks!!!

 

[George Stolz]

Show me your math.

 

[480sparky]

4/0.

2/0 is only good for 150amps per Table 310.15(B)(6).

Without knowing the numbers you used in your load calc, I don't know whether to suggest upping to something even larger.

 

[Cavie]

4/0.

2/0 is only good for 150amps per Table 310.15(B)(6).

Without knowing the numbers you used in your load calc, I don't know whether to suggest upping to something even larger.

My guess is he is using the residential exception for 200 amps using 2/0 coper or 4/o alm. If the poco ran the wire he would get something less.

 

[ptonsparky]

4/0.

2/0 is only good for 150amps per Table 310.15(B)(6)... .

:grin:

Do you wear reading glasses or should I ask if you are supposed to?

 

[infinity]

What load ampacity did you use in your calculation?

 

[480sparky]

:grin:

Do you wear reading glasses or should I ask if you are supposed to?

I looked again. 2/0 = 150 amps. Unless I missed something.

I keep saying I'm getting to old for this. Maybe I can't read anymore. :smile:

 

[infinity]

I looked again. 2/0 = 150 amps. Unless I missed something.

I keep saying I'm getting to old for this. Maybe I can't read anymore. :smile:

310.15(B)(6)
#2/0 Copper = 200 amps
#4/0 Aluminum = 200 amps

 

[480sparky]

....the 310 foot run but I will be buying aluminum as that is what is available here (Alberta Canada)
Can I use 2/0 or should I breakdown and go 4/0? aluminum

Thanks!!!

That's what I was going by....

2/0 Al = 150 amps.

 

[Randy holmes]

thanks

thanks

I was thinking 4/0. I probably will never be drawing any more than 120-130 amp at a time ever but it was a 120 amp service panel or the next size up was 200. we know where I went.


As for showing the math...what math?? I have done lots of electronic lv calculation but this? 4/0 and 2/0 al wire size (diameter size) fixed...material type fixed. length fixed load was not mentioned but max peak capacity is 165 amps give or take fo a 200 amp panel . All these are constant./ knnown values


Anywho...4/0 al is what I will get..thanks guys

Randy

 

[tryinghard]

As for showing the math...what math??Randy

In your original post you said ?I am installing a new serve at my acerage and need to calculate the cable size?My calculations show??

Should be something like the following:
1PH [D]istance = CM x VD / 2 x K x I & 1PH VD = 2 x K x I x D / CM

So:
D = 211,600 x 11.5 [230 x 5%] / 2 x 21.2 x 130

441? = 2,433,400 / 5,512, meaning you can run 441? with your service length at 130 amperes.
But if you want to load your 200A to an 80% capacity [160A] you can only run 359?

Q1: Why are you calculating/designing the utility service?

Q2: Why are you factoring a 5% voltage drop?