# Sizing wire...



## ohm it hertz (Dec 2, 2020)

Put on your sunglasses, boys. This one's gonna melt your face off.

There are a lot of variables at play in what you are asking. I am resi only but you have to consider distance, voltage drop, conductor material (Al or cu), size and material of conduit, de rating depending how many current carrying conductors needed, and the expected load on the system... just to name a few. 

Where do you work? The admins are going to ask you anyways.


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## Kevin (Feb 14, 2017)

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## Southeast Power (Jan 18, 2009)

Eatbeerdrinkpizza said:


> I need some help to understand wire sizing.. I need to run wire for a 1000amp breaker. The highest amp I’ve seen on the charts is 675. This is for 480v 3 phase about 20 ft run.
> 
> TIA
> 
> ...


Are you really an electrician? 
Please refer to your electrical system in professional terms. We call it 483 phase. 
FWIW, 1000 amps at 483 phase likes to explode if you mix up the phases.


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## Kevin (Feb 14, 2017)

Southeast Power said:


> Are you really an electrician?


I suspect OP is not an electrician but maybe an in house maintenance guy...

Whatever he does, he has to be careful around 483 phase. I hear that stuff is nasty.


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## Eatbeerdrinkpizza (Jan 16, 2021)

Southeast Power said:


> Are you really an electrician?
> Please refer to your electrical system in professional terms. We call it 483 phase.
> FWIW, 1000 amps at 483 phase likes to explode if you mix up the phases.


You don’t need to be a ****, I’m just looking for a little help. BTW, we call it 480 where I’m from. Also, if you’re going to be snide, at least provide some information...


Sent from my iPad using Tapatalk


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## Eatbeerdrinkpizza (Jan 16, 2021)

Kevin_Essiambre said:


> I suspect OP is not an electrician but maybe an in house maintenance guy...
> 
> Whatever he does, he has to be careful around 483 phase. I hear that stuff is nasty.


I am an electrician, I just need help sizing wire... again... in the US we call, it 480. Are you guys always like this on this form?


Sent from my iPad using Tapatalk


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## MikeFL (Apr 16, 2016)

@Eatbeerdrinkpizza 

Please fill out your profile including and especially your Electrical Trade by clicking your avatar, then Account Settings.

It's required per the terms of use and it makes extra work for the moderators following posts from new members until you get your profile filled out.

Welcome to the forums.

Thanks and stay safe.


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## Dennis Alwon (May 9, 2009)

Eatbeerdrinkpizza said:


> I am an electrician, I just need help sizing wire... again... in the US we call, it 480. Are you guys always like this on this form?
> 
> 
> Sent from my iPad using Tapatalk



I agree there was no need for some of those comments. I apologize but when you don't fill out your profile we often assume you are not an electrician and it can be less than helpful. FWIW, I never heard 483 phase. We call 480 3 phase also.

You need to run parallel runs



> (H) Conductors in Parallel.
> (1) General. Aluminum, copper-clad aluminum, or copper
> conductors, for each phase, polarity, neutral, or grounded
> circuit shall be permitted to be connected in parallel (electrically
> ...


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## Eatbeerdrinkpizza (Jan 16, 2021)

Dennis Alwon said:


> I agree there was no need for some of those comments. I apologize but when you don't fill out your profile we often assume you are not an electrician and it can be less than helpful. FWIW, I never heard 483 phase. We call 480 3 phase also.
> 
> You need to run parallel runs


Thank you, I appreciate the legitimate response!


Sent from my iPad using Tapatalk


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## emtnut (Mar 1, 2015)

Thanks for filling out your profile as requested ... err, NVM, you didn't bother

Maybe it's a Canuck thing, but a first year apprentice knows about paralleling conductors

Stay safe !


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## Dennis Alwon (May 9, 2009)

emtnut said:


> Thanks for filling out your profile as requested ... err, NVM, you didn't bother
> 
> Maybe it's a Canuck thing, but a first year apprentice knows about paralleling conductors
> 
> Stay safe !



Maybe in Canada but I didn't do new construction or work in industrial areas when I was in the city. I don't believe I ever ran a parallel circuit or feeder... maybe once many moons ago


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## kb1jb1 (Nov 11, 2017)

Do not forget to de-rate if installing parallel conductors in the same trough or raceway. 1000 amp might need 3 sets of 500 kcmls.


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## eddy current (Feb 28, 2009)

Dennis Alwon said:


> Maybe in Canada but I didn't do new construction or work in industrial areas when I was in the city. I don't believe I ever ran a parallel circuit or feeder... maybe once many moons ago


Not all will have the experience in the field, but it is definitely something learned early on in an apprenticeship.


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## emtnut (Mar 1, 2015)

eddy current said:


> Not all will have the experience in the field, but it is definitely something learned early on in an apprenticeship.


Just like the new guy in this thread ... underground cables
I'd guess that's a first year question (maybe 2nd ?), but you would probably know for sure !

He may never work in the field with it, but he would be aware of it and how to calculate the size of wires needed.


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## cdslotz (Jun 10, 2008)

Eatbeerdrinkpizza said:


> I am an electrician, I just need help sizing wire... again... in the US we call, it 480. Are you guys always like this on this form?
> 
> 
> Sent from my iPad using Tapatalk


Yes...they are....lol


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## cdslotz (Jun 10, 2008)

emtnut said:


> Thanks for filling out your profile as requested ... err, NVM, you didn't bother
> 
> Maybe it's a Canuck thing, but a first year apprentice knows about paralleling conductors
> 
> Stay safe !


Your profile says you are a DYI extraordinaire....should we take your word for it?


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## Dennis Alwon (May 9, 2009)

cdslotz said:


> Your profile says you are a DYI extraordinaire....should we take your word for it?



As long as he is extraordinaire then we wont ban him.


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## emtnut (Mar 1, 2015)

Dennis Alwon said:


> As long as he is extraordinaire then we wont ban him.


Thanks Dennis 

Oh, and pass that on to the other Mods too please


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## Southeast Power (Jan 18, 2009)

Eatbeerdrinkpizza said:


> Thank you, I appreciate the legitimate response!
> 
> 
> Sent from my iPad using Tapatalk


You can show some appreciation by clicking on some of the advertisements in the sidebar so we can pay the rent.


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## BillyMac59 (Sep 12, 2019)

As a long time member of this forum, I look forward to others - not necessarily new members - asking questions such as this. Never in my 30+ year career have I worked on an application requiring the installation of parallel conductors. When I first saw the post, I made a mental note to check back as history has shown that many,many members here could help out a fellow electrical worker. Unfortunately, I was not surprised to see that some responses seem like they originated in a corral.......My two cents worth


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## eddy current (Feb 28, 2009)

ValeoBill said:


> As a long time member of this forum, I look forward to others - not necessarily new members - asking questions such as this. Never in my 30+ year career have I worked on an application requiring the installation of parallel conductors. When I first saw the post, I made a mental note to check back as history has shown that many,many members here could help out a fellow electrical worker. Unfortunately, I was not surprised to see that some responses seem like they originated in a corral.......My two cents worth


But was it taught to you in trade school?


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## tmessner (Apr 1, 2013)

4 runs of 250 al is what I would use. Much easier to work with, Watch out for derate depending on conduit fill. 4 conductors per phase also divides easily for conduit runs


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## emtnut (Mar 1, 2015)

ValeoBill said:


> As a long time member of this forum, I look forward to others - not necessarily new members - asking questions such as this. Never in my 30+ year career have I worked on an application requiring the installation of parallel conductors. When I first saw the post, I made a mental note to check back as history has shown that many,many members here could help out a fellow electrical worker. Unfortunately, I was not surprised to see that some responses seem like they originated in a corral.......My two cents worth


There are many 'hecklers' here, I am one at times too.
All these guys help out when they know they are helping out a fellow electrician.

From the info the OP gave, he's in WAYYYY over his head.
So the flip side of this ... we help him out, direct him, and he blows chit up or worse he gets hurt.

OP could have responded with something showing he knows what he's doing, then the members would have gone out of their way to help him.

My 2 cents


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## Eatbeerdrinkpizza (Jan 16, 2021)

Southeast Power said:


> You can show some appreciation by clicking on some of the advertisements in the sidebar so we can pay the rent.


Naw dude, with the way you yourself responded (and most of the other people on here) all I’m gonna do is give a poor rating in the app rates. 


Sent from my iPad using Tapatalk


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## emtnut (Mar 1, 2015)

Oh ...... MY .... GOSH !!!!


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## Kevin (Feb 14, 2017)

Eatbeerdrinkpizza said:


> Naw dude, with the way you yourself responded (and most of the other people on here) *all I’m gonna do is give a poor rating in the app rates.*
> 
> 
> Sent from my iPad using Tapatalk


I got a feeling that won't do much.

You're welcome to stay and get help... Provided you fill out your profile. Here is a link to help you achieve this... 
HINT: you need to use a browser! Tapatalk will not work for this!

Of course you may stay without filling it out, but most people won't help.

Or you can leave and never return. Doesn't bother me any if you choose this option....


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## mofos be cray (Nov 14, 2016)

Eatbeerdrinkpizza said:


> Naw dude, with the way you yourself responded (and most of the other people on here) all I’m gonna do is give a poor rating in the app rates.
> 
> 
> Sent from my iPad using Tapatalk


I don't think they were that bad. How are your hot dogs? Well cooked?


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## kb1jb1 (Nov 11, 2017)

Aside from many comments, this is a good question that many electricians probably could not answer correctly. I say 4 sets of 350 kcmls Aluminum. 
3 sets of 250 kills Copper.
Above 800 amps I believe you have to round down.


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## 460 Delta (May 9, 2018)

Kevin said:


> I got a feeling that won't do much.
> 
> You're welcome to stay and get help... Provided you fill out your profile. Here is a link to help you achieve this...
> HINT: you need to use a browser! Tapatalk will not work for this!
> ...


Wow, @Kevin is getting cranky now he’s a mod! And what’s with the mononym now? We have Penn and Teller, Elvis, Cher, Adele, and now Kevin!


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## Kevin (Feb 14, 2017)

460 Delta said:


> And what’s with the mononym now?


Someone complained my username didn't fit on one line... so I fixed it haha


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## emtnut (Mar 1, 2015)

Kevin said:


> Someone complained my username didn't fit on one line... so I fixed it haha


Just shorten your last name


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## 460 Delta (May 9, 2018)

Kevin said:


> Someone complained my username didn't fit on one line... so I fixed it haha


Someone, uhhuh, yep that mysterious dude .


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## tmessner (Apr 1, 2013)

depends on how many conduits you are using. 2 pipes equals


tmessner said:


> 4 runs of 250 al is what I would use. Much easier to work with, Watch out for derate depending on conduit fill. 4 conductors per phase also divides easily for conduit runs


My mistake. I forgot he is looking at 1000 amps.


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## tmessner (Apr 1, 2013)

kb1jb1 said:


> Aside from many comments, this is a good question that many electricians probably could not answer correctly. I say 4 sets of 350 kcmls Aluminum.
> 3 sets of 250 kills Copper.
> Above 800 amps I believe you have to round down.


4 sets of copper, you use the 75 deg column for sizing, then use the 90 deg column for derating to make sure the 75 deg ampacity is still good for conduit fill, temperature etc. and yes above 800 amp you can round up.


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## Kevin (Feb 14, 2017)

emtnut said:


> Just shorten your last name


I did... See? LOL


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## gnuuser (Jan 13, 2013)

tmessner said:


> 4 sets of copper, you use the 75 deg column for sizing, then use the 90 deg column for derating to make sure the 75 deg ampacity is still good for conduit fill, temperature etc. and yes above 800 amp you can round up.


Its been a while but i believe you are correct.
regardless the op is in over his head here. high current installations you have to be meticulous in your work and cleanup as well.
an arc flash from 480 @ 200 or above amps is exceedingly dangerous considering anything in the plasma arc is vaporized in an instant.


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## tmessner (Apr 1, 2013)

I think we all had to start someplace. I know the first times I cut paralleled conductors I measured, measured, measured then pulled the conductors tight next to each other then eyeballed again to make sure they were exactly the same length. I am still careful but nearly as much.


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## CMP (Oct 30, 2019)

kb1jb1 said:


> Aside from many comments, this is a good question that many electricians probably could not answer correctly. I say 4 sets of 350 kcmls Aluminum.
> 3 sets of 250 kills Copper.
> Above 800 amps I believe you have to round down.


So let's look at the next step. If he used 4 X 350 MCM sets, what size EGC and grounded conductor would he need with each set??

Since others don't have experience sizing parallel runs...


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## MotoGP1199 (Aug 11, 2014)

CMP said:


> So let's look at the next step. If he used 4 X 350 MCM sets, what size EGC and grounded conductor would he need with each set??
> 
> Since others don't have experience sizing parallel runs...


2/0 EGC
1/0 Grounded conductor(assuming 50%, but going with the parallel minimum size)


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## dspiffy (Nov 25, 2013)

ValeoBill said:


> As a long time member of this forum, I look forward to others - not necessarily new members - asking questions such as this. Never in my 30+ year career have I worked on an application requiring the installation of parallel conductors. When I first saw the post, I made a mental note to check back as history has shown that many,many members here could help out a fellow electrical worker. Unfortunately, I was not surprised to see that some responses seem like they originated in a corral.......My two cents worth


I agree, I read threads to learn. I've mostly done commercial, and I've never worked with anything above 277/480. I love reading some of the residential and industrial discussions.

Even some of the newbie questions from non-electricians are interesting to me, and there are some I wish we could respond to, as they might lead to an interesting discussion. (I get that if they were blocked but the discussion was kept open, they could theoretically read the answers.)


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## Quickservice (Apr 23, 2020)

Southeast Power said:


> Are you really an electrician?
> Please refer to your electrical system in professional terms. We call it 483 phase.
> FWIW, 1000 amps at 483 phase likes to explode if you mix up the phases.


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## Quickservice (Apr 23, 2020)

emtnut said:


> Oh ...... MY .... GOSH !!!!


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