Box Fill Calculations for sizes over #6 Awg?

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2/0 (4 Conductor) MC cable being spliced in a metal box. My cable is running straight through the box. So I must multiply the diameter of my cable EIGHT times .........Using Annex C....I know my cable size or atleast the connector is 2 1/2".

2 1/2 x 8= 20"

A 24" / 24" box sounds huge am I lost here?
 
celtic said:
or you could just ask the counter-man for some #6 split-bolts...on the bolt will be the wire range...if memory serves me: #10-6 is one; and #6-2 another...READ the range to comply with 110.3(B) considering your application.
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Mattula ,

Celtic has named one type of splicing device that works well. There are also power distribution blocks , polaris connectors, and butt-splices, to name a few more. Each one of these has advantages and disadvantages , like price , space,etc.

Ibew441dc
 
Mattula said:
2/0 (4 Conductor) MC cable being spliced in a metal box. My cable is running straight through the box. So I must multiply the diameter of my cable EIGHT times .........Using Annex C....I know my cable size or atleast the connector is 2 1/2".

2 1/2 x 8= 20"

A 24" / 24" box sounds huge am I lost here?
Click to expand...

Maybe a little bit...

The LENGHT of the box would be 20" as you indicated.....but who says it has to a "box"...a rectangle works also ;) like a through/gutter...sized at 4".
Your connector is 2 1/2" so you really only need enough room for your connectors and bushings.
4" x 20" is not that big...maybe even too small if you have catcher's mitts for hands :D
 
ibew441dc said:
Mattula ,

Celtic has named one type of splicing device that works well.
Click to expand...
That was the only brand I could remember (and find a website for!) under all the pressure of this smoking hot topic :D
 
Celtic,

I feel yer overwhelming pain!:grin:

Hopefully we got him or her on the right track.:smile:


ibew441dc
 
celtic said:
The LENGHT of the box would be 20" as you indicated
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314.28(A)(2)
When transposing cable size into raceway size in 314.28(A)(1) and (A)(2), the minimum metric designator (trade size) raceway required for the number and size of conductors in the cable shall be used.
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Doesn't this mean you don't use the connector for the cable to determine the length of the box, but use the size of the conduit that you would use if you were pulling the conductors in a conduit?

In this case, (4) 2/0 conductors looks like it fits a 2" conduit. Therefore, a 16" length would be the minimum instead of a 20" length?
 
hardworkingstiff said:
314.28(A)(2)


Doesn't this mean you don't use the connector for the cable to determine the length of the box, but use the size of the conduit that you would use if you were pulling the conductors in a conduit?

In this case, (4) 2/0 conductors looks like it fits a 2" conduit. Therefore, a 16" length would be the minimum instead of a 20" length?
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It would mean a 16" box...except for this:
Mattula said:
I know my cable size or atleast the connector is 2 1/2".
Click to expand...
I don't think Matt ever posted if the wiring method was cable or conduit...but he did mention a 2 1/2" connector ;)
8 x 2.5=20

Even IF the connector was 2" , those extra 4" could be worth the additional costs...

Section 314.28(A)(1) applies to minimum dimensions of pull and junction boxes or conduit bodies used with raceways or cables containing conductors 4 AWG or larger. For straight pulls, for example, trade size 2 conduit containing four 4/0 AWG, Type THHW conductors (see Annex C, Table C8) requires a 16-in. long pull box (8 ? 2 in. = 16 in.). It should be understood that although 16 in. is the required minimum length, a longer pull box may be desired for maximum ease in handling this size conductor.
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Above from commentary following 314.28(A)(1) ~ 2002 NECH
 
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