Sizing conduit for Compact AL conductors

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Strathead

Senior Member
I have read through my previous post and there seems to be no clear chart etc. what conduit sizes to use for these conductors. Thanks.


http://forums.mikeholt.com/showthread.php?t=142278&highlight=
Really, when you get right down to it, the sizing charts are not really OK for most feeders, since most feeders in conduit include different size conductors. With computers and smart phones nowadays, there a multitude of apps that can assist you in this.
 

cdslotz

Senior Member
Really, when you get right down to it, the sizing charts are not really OK for most feeders, since most feeders in conduit include different size conductors. With computers and smart phones nowadays, there a multitude of apps that can assist you in this.
I disagree. Except for the EG, most large feeders are the same size conductors. Most neutrals are sized the same as phase conductors.

Do these apps include size data for compact cable such as Stabiloy products?
 

Strathead

Senior Member
I disagree. Except for the EG, most large feeders are the same size conductors. Most neutrals are sized the same as phase conductors.

Do these apps include size data for compact cable such as Stabiloy products?

The EGC was the conductor I was referring to. find me a chart in the NEC that includes 4-3/0 and a #6 in a 2" PVC conduit. You still need to size the conduit for the ground.
 

cdslotz

Senior Member
Why would you instead of THHN?
There was a long discussion about this here: http://forums.mikeholt.com/showthread.php?t=141592

I assumed the XHHW-2 diameter and area sq/in were actually smaller than THHN. I could be wrong.
However, I think XHHW-2 is more common in compact Alum conductors and is more available in stock.
I looked at Southwire's site and it looks like they only have THHN with their "Sim-Pull" insulation. Have you priced that vs. XHHW-2? I think you pay a premium for that insulation.
 

kwired

Electron manager
Location
NE Nebraska
The EGC was the conductor I was referring to. find me a chart in the NEC that includes 4-3/0 and a #6 in a 2" PVC conduit. You still need to size the conduit for the ground.
There was a long discussion about this here: http://forums.mikeholt.com/showthread.php?t=141592

I disliked the tables in annex C ever since they introduced them (1996 if I remember correctly - maybe 1999). They added an additional book to an existing book with all of those. I find it just as easy or even faster to just use tables 4 and 5 than to find the right table in annex C. If you don't have all same size conductors you need to use tables 4 and 5 anyway if you want to be accurate.

I assumed the XHHW-2 diameter and area sq/in were actually smaller than THHN. I could be wrong.
However, I think XHHW-2 is more common in compact Alum conductors and is more available in stock.
I looked at Southwire's site and it looks like they only have THHN with their "Sim-Pull" insulation. Have you priced that vs. XHHW-2? I think you pay a premium for that insulation.
XHHW is a tougher and more tear resistant material than THHN. It probably does cost more.

Any conductor can be made with any insulation in general. What suppliers normally stock is because that is what people are buying. If they get enough requests to handle something they probably will start to carry it.
 
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