Why did this fail????????

Status
Not open for further replies.
LarryFine said:
What the no-you-can't side is saying is that the "max-3-350" conductors rating does not mean "or the equivalent area," right?
Click to expand...
Thats what i gather. There's not a table listed for internal diameters of LB's, only cu" and thats not enough to go on.

Rick
 
chevyx92 said:
Wrong again. Then please tell me with why there is a MAX CU IN Fill????? If you don't use the 3 conductors its listing as its MAX SIZE and want to use you less than as long as you dont go over the MAX CU IN you should be ok, IMO. If you were suppose to use just the 3 conductors and the size given, they wouldn't need to list a MAX CU IN fill. In all actuality if you could only have 3 conductors then you would not be able to pull a ground wire and all these LB's would be worthless by your point of view. Because honestly what good is a pvc LB if you can ONLY put 3 conductors in it? I don't agree with you or a few others on here. Just doesn't make sense logically. If it did then they would not make these LB's anymore and they would be phased out.
Click to expand...
The cubic inch fill info is for making splices in the fitting. If the fitting is not marked with its volume, splices are not permitted. 314.16(C)(2)
 
What if the cubic inches are stamped on the lb but not the number of conductors? Most lb's are marked not to exceed three conductors of a max size. Some lb's do not have the max # conductors listed, then do you go by the pipe fill and possibly be able to install 4 conductors?
 
That's the way that I see it as well I just was posting another question to try and help clear up what has been a sticky subject. Thanks.
 
chevyx92 said:
I don't know the article the inspector quoted yet. But just got word he failed me for having a 3" PVC LB with (4) 250 MCM AL and (1) #4 AL in the LB. From what I heard he's saying you can't have more than 3 wires in an LB!! Max fill on this 3" LB says this: MAX 3-350MCM , 178 CU IN. How am I over this? And how can he say you can only ever have 3 wires in an LB? :confused: This is starting to become a HUGE issue in a nearby city we work in. I am trying to figure out this madness because the way they are inspecting LB's and failing because of them, you might as well never use one ever again! Bottom line is if you have more then 3 wires then you are wrong according to this city, which I want to fight because then every LB existing in this world is wrong then. Need some insight please.
Click to expand...

The inspectors authority does not extend beyond his own rules. His rules must be Codified in City ordinance in writing, however it is still open for technical challenge. The fill is determined according to the Code. He is clearly wrong on the issue.
 
weressl said:
The inspectors authority does not extend beyond his own rules. His rules must be Codified in City ordinance in writing, however it is still open for technical challenge. The fill is determined according to the Code. He is clearly wrong on the issue.
Click to expand...
I don't agree that the inspector is clearly wrong on this issue. There is no provision in the code that tells us how we address the issue of an LB that does not have 6x conduit spacing where the combination of conductors is not shown on the fitting.
 
I have run into this years ago and failed. One of the other reason for failing is that the LB may be rated for a max. conductor size.
I have used 4" LB on 3" conduit run for "Bend Radius Compliance."
to the guys that are using the big j boxs as LB I love it. I will be doing that myself. So much easier to pull wire and looks nice to. Just remember to ID the neutral.
 
g@friendly said:
...I have used 4" LB on 3" conduit run for "Bend Radius Compliance." ...
Click to expand...
The only issue with that is in the case of a larger conduit fittings, that have a volume of over 100 cubic inches, the code requires support other than the conduits if the trade size of the conduit body is larger than that of the conduit. Form 7 LBs which are among the smallest LBs have a volume that exceeds 100 cubic inches when they are sized 2 1/2" and larger. 314.23(E)
 
LarryFine said:
Is there such a line of LB's?
Click to expand...

killarks PDF file advertises the 6 X and 8 x in there spec sheets, but the 6 times dimentions are inside to outside, not inside to inside. the 8 x dimentios for the "C" condulets are inside to inside
icon7.gif
.If you take the overall length minus the diameter of the pipe it fits the 6 x requirement

http://www.hubbell-canada.com/wiring/killark/PDF/2SecF/F24-F27.pdf
 
Last edited:
don_resqcapt19 said:
Yes, he is trying to change the NEC. The rule says use a fitting with 6x conduit spacing or use conductors that are equal to or smaller then those listed on the fitting. This applies to both the size and quanity of conductors. There is nothing in the NEC that says you can make a calculation to use more conductors than listed on the fitting, even if they are smaller than those on the fitting.

If Carlon wants to be able to do this, they need to send in a code proposal to make this change.
Click to expand...

So you are saying I can put in 3-350kCMil cables? How about ones rated for 15kV?

This just not logical. Logic would dictate that as far as the size of the fitting goes, you can fill it according to the corresponding conduit size fill limit that can be found in Chapter 9. If it is a fitting where splices and terminations made, this may be reduced by the volume restrictions. Why would the Code specify the fill limit when corresponding fittings can not utilize the same fill?
 
weressl said:
So you are saying I can put in 3-350kCMil cables? How about ones rated for 15kV?
Click to expand...
The making on the fitting specifies the size and number of single conductors that are permitted to be installed, not multi-conductors cables. As far as the 15kV conductors, the rules in Part IV of Article 314 apply, not those in Part II.
This just not logical. Logic would dictate that as far as the size of the fitting goes, you can fill it according to the corresponding conduit size fill limit that can be found in Chapter 9. If it is a fitting where splices and terminations made, this may be reduced by the volume restrictions. Why would the Code specify the fill limit when corresponding fittings can not utilize the same fill?
Click to expand...
Yes, it is logical...it is the same logic that tells us the minimum size of pull boxes. It is not based on the conduit fill tables.
The rules for for conductors #4 and larger have nothing to do with the volume of the fitting. They are based on the spacing between the conduits, just like when you size a pull box. These rules are there to help prevent damage to the conductors when there are being installed. If the distance between the conduit entries does not meet the 6x rule then the exception permits you to use conductors larger than #4 if the fitting is so marked. If the fitting is not marked, or you want to use a combination of conductors that is different from what is marked on the fitting, you have to find a fitting that meets the 6x between conduits rule.
 
don_resqcapt19 said:
The making on the fitting specifies the size and number of single conductors that are permitted to be installed, not multi-conductors cables. As far as the 15kV conductors, the rules in Part IV of Article 314 apply, not those in Part II.

Yes, it is logical...it is the same logic that tells us the minimum size of pull boxes. It is not based on the conduit fill tables.
The rules for for conductors #4 and larger have nothing to do with the volume of the fitting. They are based on the spacing between the conduits, just like when you size a pull box. These rules are there to help prevent damage to the conductors when there are being installed. If the distance between the conduit entries does not meet the 6x rule then the exception permits you to use conductors larger than #4 if the fitting is so marked. If the fitting is not marked, or you want to use a combination of conductors that is different from what is marked on the fitting, you have to find a fitting that meets the 6x between conduits rule.
Click to expand...

I did not talk about multiconductor cables, but single conductors. You did not answer that question.


The question concerned an LB didn't it? Or did other tangential information came into play? I did not read EVERY single post.
 
weressl said:
I did not talk about multiconductor cables, but single conductors. You did not answer that question.


The question concerned an LB didn't it? Or did other tangential information came into play? I did not read EVERY single post.
Click to expand...

Weressl i'm not taking sides on this but the example of (3) 350 kcmil 5 KV cables in a standard LB listed for (3) 350 conductors is not practical. The jam ratio comes in at 2.94 (2.8-3.2) and the LB would not allow for the bending radius of the cables.
 
They do make conduit bodies that will accept the same wire as the conduit..see the Killark reference...they just cost big $$$
They also make ones that will be sufficient for lesser fill just as they make 18, 20, and 22 cu in boxes for different "fill"
.
The problem is, IMHO, inspectors have allowed "undersize" conduit bodies to pass to the extent that when the Code is enforced, EC's hollar foul.
 
Status
Not open for further replies.
Top