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

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chevyx92

Senior Member
Location
VA BCH, VA
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.
 
physis

physis

Senior Member
Either there's a local ordinance, or he is indeed wrong. If he's wrong, I would certainly challenge him.

I'd be interested in seeing the codes he suggests have been violated.
 
LarryFine

LarryFine

Master Electrician Electric Contractor Richmond VA
Location
Henrico County, VA
Occupation
Electrical Contractor
You might start by contacting the manufacturere of the LB and asking what they would prescribe for your conductors. They might have some supporting documentation with which you can climb the AHJ food chain if necessary.
 
infinity

infinity

Moderator
Staff member
Location
New Jersey
Occupation
Journeyman Electrician
The requirement is for the LB to be sized like a pull box with 6X the trade size of the conduit or if it's less then you can use the conductor information provided by the manufacturer. IMO the code is really silent on whether or not you can use this LB with 5 smaller than listed conductors.
 
S

SEO

Senior Member
Location
Michigan
I agree with Larry. The inspector may be looking at the stamping inside the LB(PVC)that says no more than three conductors of a perticular size. I looked at three LB's sized from 1 1/4 thru 2" and they are all marked stating no more than three conductors. I'd try and get a formal ruling on the intent for stating no more than three conductors.
 
physis

physis

Senior Member
infinity said:
The requirement is for the LB to be sized like a pull box with 6X the trade size of the conduit or if it's less then you can use the conductor information provided by the manufacturer. IMO the code is really silent on whether or not you can use this LB with 5 smaller than listed conductors.
Click to expand...


Doesn't box fill apply?
 
physis

physis

Senior Member
infinity said:
Box fill would apply for conductors smaller than #4 AWG. For #4 and larger the 6X and 8X rules apply.
Click to expand...

Ok,

"boxes and conduit bodies enclosing conductors 4 AWG or larger shall also comply with the provisions of 314.28.

Shouldn't have mised that. :Smile:
 
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chevyx92

Senior Member
Location
VA BCH, VA
RUWired said:
chevyx, that is good info. but the area of 3-350 kcmil = 1.5498" sq and the area of 4-250 kcmil and 1- # 4awg = 1.6430. Your over the amount allowed by .932" sq.

Rick
Click to expand...

Yeah I now see that based on the Carlon info. But he's still wrong for "Blanketing" comments about LB's can't have more than 3 conductors. If I put 3-250MCM AL, 1- 4/0 AL(Neutral) and 1- #6 thhn I am good with that LB. :)
 
R

RUWired

Senior Member
Location
Pa.
Are you using compact conductors. If yes, then 4-250 kcmil al compact and 1- # 4 awg al compact = 1.5417. you would be under by .0087
"sq if you can convince him the the 3-350 are standard strand.
 
chris kennedy

chris kennedy

Senior Member
Location
Miami Fla.
Occupation
60 yr old tool twisting electrician
Price the LB, price a 6?6?36 wireway and my time to make two KO's. Now price your time dealing with the inspector. I have the same problem here and until we can all get on the same page, the Kennedy method for 4 wire installs.

DSCN0516.jpg
 
don_resqcapt19

don_resqcapt19

Moderator
Staff member
Location
Illinois
Occupation
retired electrician
chevyx92 said:
Not necessarily. Found this ammo that I will shoot the inspectors way for sure!
http://www.carlonsales.com/techinfo/codesstandards/CS-LB_Conduit_Body_Wirefill.pdf
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There is nothing in the NEC that can be used to support that calculation method. The sizing of pull boxes and and conduit bodies for conductors sized #4 and larger is not based on the area of the conductors.
This is a good question as the code does not currently address installing conductors in the LBs in a combination that is not marked on the LB. Maybe someone should submit the Carlon calculations as a 2014 proposal.
 
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chevyx92

Senior Member
Location
VA BCH, VA
RUWired said:
Are you using compact conductors. If yes, then 4-250 kcmil al compact and 1- # 4 awg al compact = 1.5417. you would be under by .0087
"sq if you can convince him the the 3-350 are standard strand.
Click to expand...

Actually 4-250kcmil and 1- #4 is 1.4414 IN2 so that means I'm under by .1084. :grin:
 
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