sizing PVC for bundled mobile home feeder (2/0,2/0,1,4 AL)

Status
Not open for further replies.

sokbok

Member
Location
Kansas City

Outer Diameter is 1.301
The sq" of that would be 1.329
Therefore I would need 2.5" SCH 40 PVC.

The insulation is RHW for this stuff.
The cumulative sq" for the individual conductors is 1.1 sq" so I assume the extra .2" is from the air gap between the bundled conductors.

This sounding right? thx
 

winnie

Senior Member
Location
Springfield, MA, USA
Occupation
Electric motor research
Remember that if you have a cable assembly you get to treat it as a single wire for conduit fill. Also the % limits are by area not diameter, so a cable with an od of 1.301" is as allowed in a conduit of 1.787" id.

The cable you describe would be permitted in a 1.5 sch 40 pvc. Not that I am recommending the minimum.

Jon
 
Remember that if you have a cable assembly you get to treat it as a single wire for conduit fill. Also the % limits are by area not diameter, so a cable with an od of 1.301" is as allowed in a conduit of 1.787" id.

The cable you describe would be permitted in a 1.5 sch 40 pvc. Not that I am recommending the minimum.

Jon
I don't really think the OP has a cable assembly.
 

sokbok

Member
Location
Kansas City
Hey Forum, thanks for all the responses.
I did not know that I could treat the bundled conductors as individuals. Is there a code reference here?
This mobile home feeder is RHW insulation !
From Table 9: 2/0 = .3505, 1= .2660, 4=.1333 so the cumulative sq area in inches = 1.1003.
The fill for 1.5" PVC SCH 40 is .794 so that wont work. @winnie not sure about using the inner diameter for conduit fill, I have not seen this done
before.
The fill for 2" is 1.316 so that will work.
thanks
 
Hey Forum, thanks for all the responses.
I did not know that I could treat the bundled conductors as individuals. Is there a code reference here?
This mobile home feeder is RHW insulation !
From Table 9: 2/0 = .3505, 1= .2660, 4=.1333 so the cumulative sq area in inches = 1.1003.
The fill for 1.5" PVC SCH 40 is .794 so that wont work. @winnie not sure about using the inner diameter for conduit fill, I have not seen this done
before.
The fill for 2" is 1.316 so that will work.
thanks
Something is wrong with your numbers. Should be about 35% fill in 1.5" pvc
 

LarryFine

Master Electrician Electric Contractor Richmond VA
Location
Henrico County, VA
Occupation
Electrical Contractor
And I do think it has to be treated as 1 conductor
I think that refers to jacketed cable assemblies, not twisted conductors.

If the OP is happy using 2", the rest of this discussion is academic. (Gee, that's never happened before.)
 

sokbok

Member
Location
Kansas City
Looks like you took 2 of each conductor size, not just the 2/0's.

My math was correct. I only doubled the 2/0.
But I think I used the wrong table.

Please see below.
fill calc.png
Upon review of the product's page it states that the conductor

"has a compact strand soft drawn 8000 series aluminum conductor, per ASTM B-800 & B-801."
and

"Aluminum Mobile Home Feeder cable has a type USE2/RHH/RHW-2 cross linked polyethylene (XLP) insulation. The conductors are cabled together with a green XLP insulted aluminum ground. The grounded (neutral) conductor is identified by a longitudinal white stripe. "

So I now think I should use the compact conductor table, Table 5A.
calc 2.png

So with that math, this RHW mobile home feeder WILL fit in a 1.5" SCH 40 PVC which has a fill of .794.

What is still kinda bugging me is that the product specifies it has an outer diameter of 1.301, which
is 1.329 sq inches. Which is of course much bigger then .794, but Table 9, note 6 states to use the values for the individual conductors, so I think I can ignore this.

Table 9, note 9 states that if this was a cable I can treat it as 1 conductor, but it has no jacket, so I think it is not a cable and needs 40% fill, because I guess a jacket is what makes something a cable.

Again, THANK YOU for all the comments and input. Again this is the product:

 
Yes every aluminum conductor I have ever seen is compact stranded.

Yes you have 4 conductors so 40% fill.

By the way, Google "southwire conduit fill calculator" it has options for compact conductors unlike many other fill calculators.
 
Status
Not open for further replies.
Top