# parallel 600 KCMIL AL for 800 amp Service



## macmikeman (Jan 23, 2007)

Sounds ok to me, but of course I didn't even bother to look at the tables in the code book for an answer before I posted mine.....................


Sounds good,,, maybe,,,,,,,,,,,,, why don't you look at the the tables before you post?


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## Southeast Power (Jan 18, 2009)

macmikeman said:


> Sounds ok to me, but of course I didn't even bother to look at the tables in the code book for an answer before I posted mine.....................
> 
> 
> Sounds good,,, maybe,,,,,,,,,,,,, why don't you look at the the tables before you post?


The variable seems to be in the 60 deg, 75 deg and the 90 deg column.


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## HertzHound (Jan 22, 2019)

Single main breaker?


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## Forge Boyz (Nov 7, 2014)

....


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## frenchelectrican (Mar 15, 2007)

Southeast Power said:


> Gents,
> We have a building with a historical peak load a bit under 500amps.
> Would using parallel 600 aluminum for an 800 amp service be acceptable for this building in your opinion?
> 
> Thank you for any constructive input.


Hey SP.,,

the issue will nail ya is the numbers of main OCPD is this a single main or multi main ? that will play the factor of sizing the conductor.


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## Cow (Jan 16, 2008)

Southeast Power said:


> Gents,
> We have a building with a historical peak load a bit under 500amps.
> Would using parallel 600 aluminum for an 800 amp service be acceptable for this building in your opinion?
> 
> Thank you for any constructive input.


340A x 2 = 680A conductor ampacity. Assuming no derating.


*If one service disconnect:*

240.4(B) would allow you to install this wire on a next-size-up 700 amp rated OCPD per 240.6(A)


*If multiple service disconnects:*

230.42(A) leads us to 220.87(exc) which allows you to size your conductors to no less than the peak demand ampacity.


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## Southeast Power (Jan 18, 2009)

MTW said:


> Call a professional. :thumbsup:


I thought you guys would want to comment on some field design rather than jerking it into each others back pockets. :vs_cool:


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## Southeast Power (Jan 18, 2009)

frenchelectrican said:


> Hey SP.,,
> 
> the issue will nail ya is the numbers of main OCPD is this a single main or multi main ? that will play the factor of sizing the conductor.


It's a single main. Ill have to change the trip unit..


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## tmessner (Apr 1, 2013)

800 amps, 75c column: 3 400 kcmil al or 4 250 kcmil al depending on your lug size. We try to use 250 for most everything because it is easier to use and works for even number multiples 200, 400 , and so on. It also divides evenly for parallel pipe runs


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## brian john (Mar 11, 2007)

90C if the conductors are terminated on bus in lieu of the CB or fuse and the jumpers are rated from the bus to the CB at 75C for 800 amps to the CB.


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## Dennis Alwon (May 9, 2009)

If you can't be constructive that please don't respond. Stop messing up every thread. You all don't get enough in the off-topic forum???? Please don't respond to this.


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## brian john (Mar 11, 2007)

Dennis Alwon said:


> If you can't be constructive that please don't respond. Stop messing up every thread. You all don't get enough in the off-topic forum???? Please don't respond to this.


What are you talking about or who are you addressing?


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## CoolWill (Jan 5, 2019)

brian john said:


> What are you talking about or who are you addressing?


He meant to post that on Holt, where he spends most of his time forum time.


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## frenchelectrican (Mar 15, 2007)

Southeast Power said:


> It's a single main. Ill have to change the trip unit..


Ya going down to 700 amp range ? I know there is a cutoff point is 800 so you can use 750 amp if you desired to do that. 

Cow did post a good reminder of that. 

If you used 700 amp single main OCPD point then you can use the twin 600 al conductors as long no derating nail ya. 

Is any reason why cant ya use 750 al conductors ?


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## Southeast Power (Jan 18, 2009)

frenchelectrican said:


> Ya going down to 700 amp range ? I know there is a cutoff point is 800 so you can use 750 amp if you desired to do that.
> 
> Cow did post a good reminder of that.
> 
> ...


The 600s are installed. We typically used them for 400amp services. 
Somehow on this project, for sure my responsibility, parallel 600s were installed.
It's overhead which is rare for us.
Also, if I remember correctly, we had to crimp pin terminals, aka lollipops, for them to fit in the, I believe, 500 lugs.

The load is less than 500 amps, I didn't recall 750 amp as a standard OCP size.


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## Wiresmith (Feb 9, 2013)

Parallel 600s but then you mentioned overhead, what ampacity are we working with? Free air? What's the fear with using smaller ocpd If it is still large enough for load? Its better for breaker to trip than circuit overheat, if wire ampacity is enough then appropriate ocpd size is enough, especially if you're using the round up allowance. Remember it's not instantaneous, trip curves give wiggle room.


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## Southeast Power (Jan 18, 2009)

There has been somewhat of a development on my 800 amp project.
I put a recorder on the service for about 6 weeks. The amperage was in the low 500s, not anything above 537 amps. 
Over the weekend, I visited the site and noticed that they are now peaking out at just over 610 amps. 
Im now not so comfortable with changing the trip unit out to 700 amps at this point.
Next is a more interesting development with some possible benefit on my side.
The owner has decided to purchase, for installation, a 60hp compressor. This will be the largest motor in the facility and now I'm faced with a complete certainty that we are now going to be greater than any exception and well above the 800amps we thought we were setup for.

The bit of silver lining is that all of the equipment we supplied is 1200amp frame. The bottle neck is the 800amp indoor ATS the owner bought from his generator supplier. 
The bad thing is that Im about $18k out of pocket on this project right now and we haven't been at the site in 4 months.


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## CoolWill (Jan 5, 2019)

Southeast Power said:


> There has been somewhat of a development on my 800 amp project.
> I put a recorder on the service for about 6 weeks. The amperage was in the low 500s, not anything above 537 amps.
> Over the weekend, I visited the site and noticed that they are now peaking out at just over 610 amps.
> Im now not so comfortable with changing the trip unit out to 700 amps at this point.
> ...


Can you add another run of 600s? Tell the customer that his 60 HP compressor has thrown it all off and he needs to go up a notch or two.


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## Southeast Power (Jan 18, 2009)

My 1200 amp equipment can handle 3-750s. The ATS can only handle 500s but, the compact 600s fit without lollipops.
I offered the owner the option of him paying the $4,000 for swapping the 600 Al for 500 copper. I will provide 32 man hours to replace the wire, he pays for the wire.


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