Quadraplex cable conduit fill

[toddkrein]

I need to run 4/0-4/0-4/0-2/0 cable (Wake Field from Southern) through a buried conduit, and I'm unsure how to apply the fill capaity rule. If I look at them as four independent 4/0 wires, I can run them through a 2" conduit. If I look at it with a total cross section of 1.588", I need a 3" conduit.

Which is correct?

 

[luckylerado]

Multi conductor cables are considered a single conductor when calculating fill per Chapter 9 note 9. Sounds like an SE cable though which if true would not be allowed underground per 338.12(A)(2)

 

[wwhitney]

Does the cable have an overall jacket, or is it just 4 individual conductors spiraled together? If the latter, then the 2017 NEC clarified that it should be treated as 4 individual conductors for conduit fill purposes. See Note 9 to Chapter 9, Table 1.

Cheers, Wayne

 

[toddkrein]

URD

URD

It's URD, not SE, so I think I'm OK there. It's four twisted conductors, no sheath.

Ch 9 note 5 says that a multi-conductor shall use actual dimensions, and note 9 says that a multi-conductor shall be treated as a single conductor for fill.

That implies to me that this counts as one wire in pvc (table 4) I can fill to 53%, or 1.744 sq. in.

Does that make sense?

(I'm looking at 2014 version.)

 

[toddkrein]

Thanks Wayne!

Thanks Wayne!

Aha! I found the change in the 2017 version notes, and now all is clear. The heavens have opened, and happy rays of enlightenment fall upon me.


But seriously, thanks very much.

 

[REDICO]

2" will work but I don't like to go with the bare minimum size conduit that will fit. Jam ratio and friction are less if you oversize a bit and it will still fit inside your enclosure. Easier pull. Take care of your body and equipment.

Sent from my SM-S975L using Tapatalk

 

[toddkrein]

Cost vs pain

Cost vs pain

Yes, oversize will make the job easier, but it's a 400' run, so the cost different between 2" and 3" is pretty significant.

Hmm...

 

[electricguy61]

Yes, oversize will make the job easier, but it's a 400' run, so the cost different between 2" and 3" is pretty significant.

Hmm...

And your labor cost savings for trying to pull that wire through 2" vs 2 ½" or 3"conduit 400' will more then pay for the added material cost.

JMTCW

 

[kwired]

And your labor cost savings for trying to pull that wire through 2" vs 2 ½" or 3"conduit 400' will more then pay for the added material cost.

JMTCW

That depends on what you are pulling with, and some other conditions. Straight shot with no bends might pull easier through 2 inch compared to 3 inch with 360 degrees of bends.