# LB sizes and wire gauges



## TOOL_5150 (Aug 27, 2007)

So, I have an LB that has a cubic inch stamped on it, as well as MAX 3C #2 This is for a 1-1/4" as well as a 1-1/2" LB. I want to run 3 #2's and a #8 for ground. My pipe is going to be 1-1/4 LFMC With these 2 LBs, it is not possible, as I read it, correct? I just want to make sure there are no other ways around this before I go installing a 3R junction box and nippeling out the back.

~Matt


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## macmikeman (Jan 23, 2007)

You can use 1-1/2" lbs with reducing bushings also. Ends up looking a tiny bit better than hanging a box half off a corner, and there are mounting holes in the rear of the 3r boxes that can let moisture into the box when the box is hanging out in the weather partially. (So what the wire is almost always wet rated anyway, but I digress,310.15 code).


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## TOOL_5150 (Aug 27, 2007)

But this is my issue - the inside of a 1-1/4 AND 1-1/2 LB both say: MAX 3C #2 So upsizing to 1-1/2 technically gains me nothing. I dont have a 2" lb to see its max rating.

~Matt


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## macmikeman (Jan 23, 2007)

TOOL_5150 said:


> But this is my issue - the inside of a 1-1/4 AND 1-1/2 LB both say: MAX 3C #2 So upsizing to 1-1/2 technically gains me nothing. I dont have a 2" lb to see its max rating.
> 
> ~Matt


Sorry about that. 2"= 3 # 4/0 max You will be fine with a 2".


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## KayJay (Jan 20, 2008)

TOOL_5150 said:


> So, I have an LB that has a cubic inch stamped on it, as well as MAX 3C #2 This is for a 1-1/4" as well as a 1-1/2" LB. I want to run 3 #2's and a #8 for ground. My pipe is going to be 1-1/4 LFMC With these 2 LBs, it is not possible, as I read it, correct? I just want to make sure there are no other ways around this before I go installing a 3R junction box and nippeling out the back.
> 
> ~Matt


Since the conductors are larger than #6 and your not splicing them in the conduit body, why wouldn’t the number of conductors allowed in the LB be based on the last sentence of 314.16[C],[1], which is what you would use to size your conduit bodies per 314.16?

“The maximum number of conductors permitted shall be the maximum number permitted by Table 1 of Chapter 9 for the conduit or tubing to which it is attached.”

I don’t see that 314.28[A],[3] applies here either as the LB’s are not actually being used as pull ells or junction boxes. 

The UL Whitebook covers them under outlet boxes, which is probably why they are included in NEC 314.

Conduit Bodies — Conduit bodies that are not provided with a volume marking are not intended to enclose splices, taps or devices.

Conduit bodies that are provided with a volume marking are covered under Metallic Outlet Boxes (QCIT) or Nonmetallic Outlet Boxes (QCMZ). Conduit bodies Classified
for use with specific conduit body covers and conduit body covers
Classified for use with specific conduit bodies are covered under Conduit
Bodies and Covers Classified for Use with Specified Equipment (QCKW).


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## macmikeman (Jan 23, 2007)

KayJay said:


> Since the conductors are larger than #6 and your not splicing them in the conduit body, why wouldn’t the number of conductors allowed in the LB be based on the last sentence of 314.16[C],[1], which is what you would use to size your conduit bodies per 314.16?
> 
> “The maximum number of conductors permitted shall be the maximum number permitted by Table 1 of Chapter 9 for the conduit or tubing to which it is attached.”
> 
> ...


314.16 Boxes and conduit bodies enclosing conductors 4 AWG
or larger shall also comply with the provisions of 314.28. Op is placing #2 insulated conductors into his lb.


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## KayJay (Jan 20, 2008)

macmikeman said:


> 314.16 Boxes and conduit bodies enclosing conductors 4 AWG
> or larger shall also comply with the provisions of 314.28. Op is placing #2 insulated conductors into his lb.


OP did say #2. Oops… Mongo make mistake. :001_huh:


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## macmikeman (Jan 23, 2007)

KayJay said:


> OP did say #2. Oops… Mongo make mistake. :001_huh:


Quite allright. The more times I get to go hunt down something in the code book, the better I get at my code- eology. You were just trying to help me.:thumbsup:


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