CU TO AL

[Alwayslearningelec]

Regarding going from CU to AL THHN. Does this make sense?

150A 3P/3W calling for 3 #1/0 & 1#6G CU THHN and 1-1/2" EMT. If going to AL THHN I'd have to use 3/0 and go to 2" EMT?
150A 3P/4W calling for 4#1/0 & 1#6G CU THHN and 2" EMT. If going to AL THHN I'd have to use 3/0 but could keep still use 2" EMT?

 

[Alwayslearningelec]

Lastly,

600A 3P/4W calling for 2 sets 4 #350 & 1#1G CU THHN and (2) 3". If going to AL you need #500 but conduit could stay at 3"?

Seem like sometime conduit doesn't need to be upsized when going from CU to AL.

 

[ptonsparky]

Not sure where you are headed with this thread, but yes, sometimes you don’t need to change conduit sizes.

Add XHHW to your mix.

 

[Alwayslearningelec]

Not sure where you are headed with this thread, but yes, sometimes you don’t need to change conduit sizes.

Add XHHW to your mix.

Was simply presenting examples and asked question.
Where are you heading with the XHHW?

 

[ptonsparky]

Was simply presenting examples and asked question.
Where are you heading with the XHHW?

Less area, easier to pull.

 

[Alwayslearningelec]

Less area, easier to pull.

XHHW is larger OD and heavier for same given size THHN

 

[ptonsparky]

XHHW is larger OD and heavier for same given size THHN

.? My chart shows compact stranded With less area.

 

[electrofelon]

I have found AL to always be compact stranded, whether it's THHN or XHHW.

 

[kwired]

I have found AL to always be compact stranded, whether it's THHN or XHHW.

These days it usually is compact, but can't necessarily count on it being compact unless you specifically ask when ordering.

So compact THHN will be smaller than compact XHHW, I think, I know it should be smaller than standard XHHW and nylon outer coating will pull easier than the XLPE does, but XLPE will resist scuffing and other abuse a little better.

 

[ptonsparky]

Do the areas in table 9 mean nothing, or am I reading them wrong? It wouldn’t be the 1st occurrence.

 

[kwired]

Lastly,

600A 3P/4W calling for 2 sets 4 #350 & 1#1G CU THHN and (2) 3". If going to AL you need #500 but conduit could stay at 3"?

Seem like sometime conduit doesn't need to be upsized when going from CU to AL.

The 350's are too large for 2.5" but do not "fill" the 3", there happens to still be enough room for 500's in the 3".

 

[AC\DC]

Do the areas in table 9 mean nothing, or am I reading them wrong? It wouldn’t be the 1st occurrence.

ON table 5A in my 2020 says if you going off the 500kcmil that Post#2 stated
For compact Aluminum
Approximate Area In2
THHN
500 =.6151

XHHW
500= .6082

Seems your right though without looking I would of though THHN would be less

 

[ptonsparky]

Lastly,

600A 3P/4W calling for 2 sets 4 #350 & 1#1G CU THHN and (2) 3". If going to AL you need #500 but conduit could stay at 3"?

Seem like sometime conduit doesn't need to be upsized when going from CU to AL.

Checking my spreadsheet to see if it is correct, I get 2.5 inch for the CU and 3 for the AL.
2.253 Sq In vs 2.9854

 

[kwired]

Checking my spreadsheet to see if it is correct, I get 2.5 inch for the CU and 3 for the AL.
2.253 Sq In vs 2.9854

I do recall running 500 compact aluminum in 2.5" before. Had minimal neutral load and smallest neutral allowed though.