3" Condulet Over Fill?

[customelectric]

Hi Guys.

I have a 3" Condulet Rated for (3) # 300MCM Conductors.
I have (3) 250MCM Conductors plus 1/0 ground installed and am being told that the ground wire has now made this conduit body over filled.
Anybody?...

Does the 6 X's rule apply to condulets now as well?

Thanks for the help

 

[jumper]

Hi Guys.

I have a 3" Condulet Rated for (3) # 300MCM Conductors.
I have (3) 250MCM Conductors plus 1/0 ground installed and am being told that the ground wire has now made this conduit body over filled.
Anybody?...

Does the 6 X's rule apply to condulets now as well?

Thanks for the help

See 314.28

 

[infinity]

Yes the 6X and 8X rules apply to conduit bodies. I agree that the EGC puts you over the maximum number of conductors permitted by the marking which is 3.

 

[Dennis Alwon]

I never understood this. How does the 6x rule apply to lb's. A 2" lb would have to be a minimum of 12. I don't believe they are.

 

[augie47]

It's one of those areas in the Code that could use some work. 314.28 apples to conduit bodies, but (A)(3) allows smaller dimensions if the pull body is listed for and marked with the maximum number of conductors permitted.
All is fine until you want to install some combination of conductors that is not listed as in the OPs situation.

 

[infinity]

I never understood this. How does the 6x rule apply to lb's. A 2" lb would have to be a minimum of 12. I don't believe they are.

I agree that this section is poorly written. As it is worded now a great number of standard sized conduit bodies cannot be used with conductors greater than #6.

 

[suemarkp]

Use a giant condulet box with reducers to get you to 3". Not sure if a 4" condulet would have the wall spacing you need or not. Hopefully its an LB type you need.

 

[don_resqcapt19]

I never understood this. How does the 6x rule apply to lb's. A 2" lb would have to be a minimum of 12. I don't believe they are.

It applies because of the rule in 314.28.

314.28 Pull and Junction Boxes and Conduit Bodies.

Boxes and conduit bodies used as pull or junction boxes shall comply with 314.28(A) through (E).​

314.18(A) tells us that these rules only apply to installations of #4 and larger conductors.
314.28(A)(3) lets us use conduit bodies smaller than what is required by the 6X rule if they are listed and marked with the maximum number and size of conductors that you are permitted to install.
The issue is that there is no code method of making a field calculation for other combinations of conductors. I understand the manufacturer's instructions often include combinations other than those marked on the conduit body, but the code rule says it has to be marked on the conduit body.​

 

[hyetal]

3 300kcm =.936sq in (bare conductors) .312x3.: 3 250+ 1/0=(.260?3=.78 +.109)=
889sq in. .047sq in to spare.OP did not specify wire type

 

[don_resqcapt19]

3 300kcm =.936sq in (bare conductors) .312x3.: 3 250+ 1/0=(.260?3=.78 +.109)=
889sq in. .047sq in to spare.OP did not specify wire type

What code section lets you do a field calculation to permit a combination of conductors to be install in a conduit body that does not comply with the 6X or 8X rules that are found in 314.28?

 

[hardworkingstiff]

I assume most everyone has seen this, but in case you haven't.

http://www.carlonsales.com/techinfo/codesstandards/CS-LB_Conduit_Body_Wirefill.pdf

 

[Dennis Alwon]

It applies because of the rule in 314.28.

314.18(A) tells us that these rules only apply to installations of #4 and larger conductors.
314.28(A)(3) lets us use conduit bodies smaller than what is required by the 6X rule if they are listed and marked with the maximum number and size of conductors that you are permitted to install.
The issue is that there is no code method of making a field calculation for other combinations of conductors. I understand the manufacturer's instructions often include combinations other than those marked on the conduit body, but the code rule says it has to be marked on the conduit body. [/LEFT][/SIZE][/FONT][/SIZE][/FONT]

Thanks Don, I thought I had read that before but I was looking too fast and went right over that

 

[hardworkingstiff]

I just checked with the AHJ here, and got confirmation that if you do the fill calculations for the conductors you want to install in this conduit body and it does not exceed the fill calculations for the rating of the body, then you are good to go (it will pass in Wilmington).

 

[Dennis Alwon]

I assume most everyone has seen this, but in case you haven't.

http://www.carlonsales.com/techinfo/codesstandards/CS-LB_Conduit_Body_Wirefill.pdf

That makes no sense. If the unit is marked for 3 - 3/0 then I would not think any 4/0 conductors could be used..yet they say you can. I understand the volume thing but not with 4/0

 

[Dennis Alwon]

I just checked with the AHJ here, and got confirmation that if you do the fill calculations for the conductors you want to install in this conduit body and it does not exceed the fill calculations for the rating of the body, then you are good to go (it will pass in Wilmington).

Even if larger than the size given? Why not just a fill capacity instead...silly

 

[hardworkingstiff]

That makes no sense. If the unit is marked for 3 - 3/0 then I would not think any 4/0 conductors could be used..yet they say you can. I understand the volume thing but not with 4/0

I agree, and I also don't understand how they get by not having to comply with 314.28.

I would hate to pull some larger conductors through a C (pull them out then back in) with the short distance in that body. I don't think you could ever get the conductor to straighten out, and I bet the insulation gets nicked.

But, 8 times is also a bit more than I would need.

 

[don_resqcapt19]

That makes no sense. If the unit is marked for 3 - 3/0 then I would not think any 4/0 conductors could be used..yet they say you can. I understand the volume thing but not with 4/0

That is the issue...the manufacturer can have written information that gives a lot of different combinations of conductors that could be used with conduit bodies that do not meet the 6x or 8X rules in 314.28, but the only combination permitted by the code rule is the one or ones (I have never seen more than one combination listed on the conduit body) marked on the conduit body.
The second issue is that there is no provision in the NEC that permits field calculations, or even the other combinations listed in the manufacturer's published information.

 

[hardworkingstiff]

The second issue is that there is no provision in the NEC that permits field calculations, or even the other combinations listed in the manufacturer's published information.

Using that logic, I would not be allowed to install 5 #4 THWN conductors in an LB that had a stamp of 3 #4/0 XHHW max.

If I did that, the job should fail inspection.

 

[infinity]

Using that logic, I would not be allowed to install 5 #4 THWN conductors in an LB that had a stamp of 3 #4/0 XHHW max.

Like it or not according to the NEC that would be a violation. As Don and others have said the NEC is pretty clear on this, comply with the 6X and 8X rules or what's stamped within the conduit body otherwise use a larger CB or a pull box.

 

[don_resqcapt19]

Using that logic, I would not be allowed to install 5 #4 THWN conductors in an LB that had a stamp of 3 #4/0 XHHW max.

If I did that, the job should fail inspection.

Show me the code section that says you can install the five #4s in a conduit body marked for three 4/0s.