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Discussion Starter · #1 ·
My '11 highlights 'or conduit body' twice in 314.28(a)(2).

Has the old LB raceway/ jb debate suffered a substantial change here?

I'm reading a 3" LB needs to have 6X depth, from it's cover on in.....?

The following EX's ref to 'opposite a removable cover ' confuses me even further...removable LB cvr, or box cvr?

caffeinated adhd has the better of me this a.m. .....:(

~CS~
 

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My '11 highlights 'or conduit body' twice in 314.28(a)(2).

Has the old LB raceway/ jb debate suffered a substantial change here?

I'm reading a 3" LB needs to have 6X depth, from it's cover on in.....?

The following EX's ref to 'opposite a removable cover ' confuses me even further...removable LB cvr, or box cvr?

caffeinated adhd has the better of me this a.m. .....:(

~CS~
Yes they mean with the cover on.
 

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Conduit bodies (LL, LR, LB, C) are all now to be sized the same as we would a box with respect to 314.28.

The distance between a conduit entry and an opposite removable cover is based on the permitted bending radius in 312.

The change seems subtle at first but it has caused headaches for some contractors especially after they have the conduit ran.

Pete
 

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Discussion Starter · #4 ·
Thank you Pete, yet i'm still stymied....:001_huh:

the Ex refers to T312.6(A)

so perhaps applying a field example would help.....?

say we have 3---250kcmil in a 3" raceway & pass through a 3" LB

The 'wires per terminal' part confuses me, because there no terminals would exist in an LB, unless said LB was being used as a JB

Am I missing the obvious.....?:blink:

~CS~
 

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314.28(A)(2) Exception: Where a raceway or cable entry is in the wall of
a box or conduit body opposite a removable cover, the distance from that wall to the cover shall be permitted to comply with the distance required for one wire per terminal in Table 312.6(A).


So in your example, using 250 kcmil, Table 312.6(A) requires 4 1/2 inches from the conduit entry to the removable cover.

I don't have a 3" LB handy but I would assume that to receive a listing from an NRTL the LB (or any conduit body for that matter) would need to meet the minimum dimension from 312.6(A) based upon the largest conductors that could be contained in the conduit body.

If you have one in your shop, and feel so inclined, check to see what the distance is from the conduit entry to the cover. I'm actually curious because, honestly, I've never checked this on an inspection or installation.

Pete
 

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Discussion Starter · #8 ·
That is not anything new...it was in the 99 (370-28) code and probably older codes too, but the 99 is the oldest I have on the computer and I don't want to go dig the older books out.
which references T373-6(a) ('99) in the same manner as 314.28 references T312.6(A) ('11)

interestingly enough, the '99 370.28 refers to 'boxes and conduit bodies', while the '11 change highlights 'or conduit body'

this is old news , so just what has changed in the '11? :001_huh:

............and why am i out in the barn measuring these? (2" best i could do)



~CS~
 

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The charging statement in 370-28 and 314.28 use the wording "boxes and conduit bodies". That wording applies to the complete section. The words "or conduit bodies" were added to 314.28(A)(1) & (A)(2) by the panel action on proposal 9-83 without out any substantiation or panel comment. It did not change anything because the charging statement in 314.28 included conduit bodies for the complete section.

As far as the conduit bodies in the pictures, if they are being used with conductors #4 and larger, then the distance between the conduit entries has to be 6 times the trade size of the conduit. That is in addition to being require to have a depth that is required by 314.28(A)(2) Exception.
 

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Discussion Starter · #10 ·
The charging statement in 370-28 and 314.28 use the wording "boxes and conduit bodies". That wording applies to the complete section. The words "or conduit bodies" were added to 314.28(A)(1) & (A)(2) by the panel action on proposal 9-83 without out any substantiation or panel comment. It did not change anything because the charging statement in 314.28 included conduit bodies for the complete section.
So this is simply a clarification by their technical correlation commity ?

That would be understandable....



As far as the conduit bodies in the pictures, if they are being used with conductors #4 and larger, then the distance between the conduit entries has to be 6 times the trade size of the conduit. That is in addition to being require to have a depth that is required by 314.28(A)(2) Exception.

Let's see if i can unfuzz myself then....

Appleton's Moguls seem to address both dimensional requirements

Oz-Gedney , as well as

Cantex have dimensional charts.

So much for my trip to the barn....:rolleyes:

Using the Cantex chart image, we would be dealing with dimensions C & E


in the case of the 2" pix posted the dimensions are>
CTX-5133668 2">>> 9-13/16" & 3-3/8" respectively

So no matter what fill and/or wire size one chooses in say, T8 (RMC) , one could juxtapose dim. B (3 3/8" in this case) to T312.6A , WPT#1 stating the largest wire allowed would be a #1

~CS~
 

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It is interesting that the NEC has made it very difficult to comply with standard equipment. Now most LB's are marked - for instance a 2" lb I believe is marked for 3/ 4/0 conductors. I think this would be allowed
 

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Discussion Starter · #12 ·
It is interesting that the NEC has made it very difficult to comply with standard equipment. Now most LB's are marked - for instance a 2" lb I believe is marked for 3/ 4/0 conductors. I think this would be allowed
EGGZACTLY!

While I do appreciate you're ability to describe the crux of the issue in such a short concise manner , please allow me to peck that point apart here Denny>

from the manufacturer's spec page we're given the impression said 2" LB is good for just what you've stated, 3-4/0's

In fact it's stamped inside the LB's in my barn...

LB-200 2 31
⁄4 35
⁄8 95
⁄8 23
⁄4 91
⁄8 105
⁄8 70.0 3 #4/0AWG
Yet according to the code loop , which is no NEW loop, we can't by code requirements install anything larger than a #1

HOW then, can this be listed for the sizes the manufacturer describes ?

Third Party Certification:
UL Listed E-18095
Suitable for wet locations when used
with gasketed covers.

CSA Certified: 009795
Suitable for wet locations when used
with gasketed covers.

Applicable Third Party Standards:
UL Standard: 514A

CSA Standard: C22.2 No. 18
Fed Spec: A-A-50563
NEMA: FB-1, FB-2.10
~C S~
 

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So this is simply a clarification by their technical correlation commity ?

That would be understandable....






Let's see if i can unfuzz myself then....

Appleton's Moguls seem to address both dimensional requirements

Oz-Gedney , as well as

Cantex have dimensional charts.

So much for my trip to the barn....:rolleyes:

Using the Cantex chart image, we would be dealing with dimensions C & E


in the case of the 2" pix posted the dimensions are>
CTX-5133668 2">>> 9-13/16" & 3-3/8" respectively

So no matter what fill and/or wire size one chooses in say, T8 (RMC) , one could juxtapose dim. B (3 3/8" in this case) to T312.6A , WPT#1 stating the largest wire allowed would be a #1

~CS~
Unless marked for the maximum size and number of conductors, that fitting is not suitable for use with conductors #4 and larger, because the distance between the conduit entries is less than 12" (6 times the trade size of the conduit)
 

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The real issue with the markings on the conduit bodies, is the fact that they almost always say 3 conductors of x size. There is no code provision that permits you to do a field calculation and use 4 conductors of a smaller size. There is also no provision to let you use the other combination of sizes that are shown in the manufactures instructions. A reasonable AHJ would permit the sizes in the instructions but the code does not say that.

A good place for 2017 proposal.
 

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