Wire size for a 500' run

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gmtt

Member
What would be the proper wire size for a 500' run, carrying 60a current? Thanks.

480sparky

Senior Member
Copper or aluminum?

Voltage & phase?

Overhead (open air), direct burial, or in a raceway?

Any ambient temp issues?

How many conductors?

gmtt

Member
240v, 2p, 3w, running from gnd flr all way to 49th flr of a building

480sparky

Senior Member
I get 1/0 copper.

shamsdebout

Senior Member
I would use 2/0, this would ensure max 3% voltage drop. I assumed you were using copper.

charlie b

Moderator
Staff member
I would agree with the 1/0 copper, presuming that the "2p" was intended to mean "single phase, two pole."

pms_electric

Member
For a 240V single phase three wire, 500 feet long. I calculate a 4.61% drop with 3/0 copper

yired29

Senior Member
I would use 2/0, this would ensure max 3% voltage drop. I assumed you were using copper.

I also get 2/0

CM = 2 x K x I x D / VD

CM = 2 x 12.9 x 60 x 500 / 7.2 = 107,500

1/0 = 105,600
2/0 = 133,100

This is assuming that it is actually a 60 amp load not just a 60 amp OCPD. If this is a 60 amp OCPD than the actual load would probably be less than 60 amps. More like 60 X .8 = 48 amp load.

gmtt

Member
Thanks guys. I found a voltage drop calcualtor in the web. Actually it is a 30A generator pushing power to the 49th flr. I am using 2 AWG copper with a drop of 2.9%. Thanks.

480sparky

Senior Member
Thanks guys. I found a voltage drop calcualtor in the web. Actually it is a 30A generator pushing power to the 49th flr. I am using 2 AWG copper with a drop of 2.9%. Thanks.

If you're going up the building, wouldn't the voltage get higher as you go?

yired29

Senior Member
Thanks guys. I found a voltage drop calcualtor in the web. Actually it is a 30A generator pushing power to the 49th flr. I am using 2 AWG copper with a drop of 2.9%. Thanks.

Don't forget if you are using A EGC look at 250.122 (B).

shamsdebout

Senior Member
Thanks guys. I found a voltage drop calcualtor in the web. Actually it is a 30A generator pushing power to the 49th flr. I am using 2 AWG copper with a drop of 2.9%. Thanks.

Can you share the one you found?

shamsdebout

Senior Member
There is one on this site.

Yeah I am not too confident with that one to tell you the truth.

One-eyed Jack

Senior Member
Yeah I am not too confident with that one to tell you the truth.

Bussman fuse site has one I think. I may have the spelling wrong so Google to get a selection. I got all the same answers that all the others got using the same parameters.

Dennis Alwon

Moderator
Staff member
Here is one calculator. #1 is what is needed if the load is 20 amps. If it is 15 amps then you need #2

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Dennis Alwon

Moderator
Staff member
This one gave the same results the other ones I tried. Works for me!!
I edited my post And it is wrong. I see now that it is 60 amps and for that I get 2/0. 240 volts single phase. Damn I am careless

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qcroanoke

Sometimes I don't know if I'm the boxer or the bag
If you're going up the building, wouldn't the voltage get higher as you go?

I would also think it would slow down too....
I know I would.

One-eyed Jack

Senior Member
Here is one calculator. #1 is what is needed if the load is 20 amps. If it is 15 amps then you need #2

That did not work for me!!!!:grin:

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