j-box or LB
- Thread starter sparkytv
- Start date
- Status
- Location
- Massachusetts
sparkytv said:
350s may not fit in a 3" LB even though they fit in 3" raceway.
I would use a 6"x6"x24" trough before I would use a 24" x 24"
- Location
- New Jersey
- Occupation
- Journeyman Electrician
I installed a 3.5" LB today and it said maximum 3-400 kcmil conductors. So you 350's may or may not fit in a 3" LB. To play it safe I would follow Bob's suggestion.
micromind
Senior Member
- Location
- Fernley, NV. (near Reno)
If you go with the LB, you'll need a few other things.
1) Very strong hands. 350's don't bend all that easy in tight places.
2) A high tolerance to pain. I have scars from 10 years ago shoving big wire into LBs. You almost certainly will get a few skinned knuckles from the experience.
3) The willingness to pull it out, and start over again when you skin one of the wires against the far side of the LB in a desperate attempt to 'ram it on in'.
4) Keep a fire extinguisher handy. Since these sound like unfused conductors, your first indication of a skinned wire may well be a hole blown in the pipe.
If you use the trough, make the hole out the back as far away from the other end as possible. This will give you enough 'throw' (almost 2') to bend even 350's with relative ease. In fact, with a bit of practice, you can even pre-bend the 90's in the wire, and they'll go right in.
I know an LB looks nicer than a trough, you'll have to decide for yourself.
1) Very strong hands. 350's don't bend all that easy in tight places.
2) A high tolerance to pain. I have scars from 10 years ago shoving big wire into LBs. You almost certainly will get a few skinned knuckles from the experience.
3) The willingness to pull it out, and start over again when you skin one of the wires against the far side of the LB in a desperate attempt to 'ram it on in'.
4) Keep a fire extinguisher handy. Since these sound like unfused conductors, your first indication of a skinned wire may well be a hole blown in the pipe.
If you use the trough, make the hole out the back as far away from the other end as possible. This will give you enough 'throw' (almost 2') to bend even 350's with relative ease. In fact, with a bit of practice, you can even pre-bend the 90's in the wire, and they'll go right in.
I know an LB looks nicer than a trough, you'll have to decide for yourself.
chris kennedy
Senior Member
- Location
- Miami Fla.
- Occupation
- 60 yr old tool twisting electrician
Here POCO doesn't allow conduit bodies in this application.sparkytv said:
my 2 cents
my 2 cents
Personally I would have specified pull boxes altho if you go with an LB utilize a split bodided one (i believe this is the correct terminology) they are easier for installing cable altho I believe a pull box would be your best bet, I believe these are avaliable from crouse hinds and avaliable in a range of conduit szes, one project we specified pull boxes on the exterior of a building the owner did not want to see pull boxes I guess the thought our idea of it being an "architectural feature" or "structural member" did not fly and talking with the contractor we utilized this type of lb althouth the contractor said it would be easier will a pull box he was ok with this type of fitting. Just another reason to get the contractors involved it saves you from being on their bad side and I will never forget the project where someone put in 4"lb's and 500kcmil cable and the suprising part was when I saw the field installed completed project it got installed that way I wonder how (probally with alot of cussing and blodied nuckles) or at what expense to the cable, but it currently is in opeation...
my 2 cents
Personally I would have specified pull boxes altho if you go with an LB utilize a split bodided one (i believe this is the correct terminology) they are easier for installing cable altho I believe a pull box would be your best bet, I believe these are avaliable from crouse hinds and avaliable in a range of conduit szes, one project we specified pull boxes on the exterior of a building the owner did not want to see pull boxes I guess the thought our idea of it being an "architectural feature" or "structural member" did not fly and talking with the contractor we utilized this type of lb althouth the contractor said it would be easier will a pull box he was ok with this type of fitting. Just another reason to get the contractors involved it saves you from being on their bad side and I will never forget the project where someone put in 4"lb's and 500kcmil cable and the suprising part was when I saw the field installed completed project it got installed that way I wonder how (probally with alot of cussing and blodied nuckles) or at what expense to the cable, but it currently is in opeation...
If it has to be an LB make it an LBD or mogal fitting, they are a bit longer/bigger than the standard lb's. The ones with the roller on the farside help alot too.
http://www.appletonelec.com/pdf/A-25thru31.pdf Top of page two (A-26)
http://www.appletonelec.com/pdf/A-25thru31.pdf Top of page two (A-26)
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- Location
- Bremerton, Washington
- Occupation
- Master Electrician
Utility may not allow, or if they do, it will have to be sealed. Much easier to seal a JB than an LB.
LarryFine
Master Electrician Electric Contractor Richmond VA
- Location
- Henrico County, VA
- Occupation
- Electrical Contractor
But, how do you get the roller out to use it on the next one? :-?K2500 said:
- Location
- Massachusetts
micromind said:
I think you left out that 3 -350s in a standard 3" LB may be a code violation. :smile:
brian john
Senior Member
- Location
- Leesburg, VA
In all my years of conductor testing (megging) I have seen more faults in LB's with large conductors. To my knowledge the only faults I remember in junction boxes had to do with non compliant cable installations, the contractor used 2X4 wedges driven into the conduit and no bushings (strain relief) the weight of the cable in conjunction with the 2X4 wedges resulted in a fault.
With the LB's the faults were a mixed bag of issues related to forcing the conductors into the LB.
I guess posting this question here is the ultimate power quality question, because faulted cables will result in some power anomalies.
With the LB's the faults were a mixed bag of issues related to forcing the conductors into the LB.
I guess posting this question here is the ultimate power quality question, because faulted cables will result in some power anomalies.
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I agree - I cannot believe lb's are code compliant - anyone who has tried to stuff 500 mcm into one of those knows what I am talking about
BUT- they do make mogul conduit bodies
And I am a huge fan of " C" condilets to use instead of a j box and never use a fitting or box to turn a corner
BUT- they do make mogul conduit bodies
And I am a huge fan of " C" condilets to use instead of a j box and never use a fitting or box to turn a corner
- Location
- Illinois
- Occupation
- retired electrician
Tori,
Don
C type conduit bodies have the same size issue as LB. If the conductors installed in the C are #4 or larger then the opening of the C must be 8 times the trade diameter of the raceway or the fitting must be marked with the maximum wire size permitted.
Don
- Location
- Massachusetts
Tori said:
You would have to force me at gunpoint to use Cs in place of a nice long trough sized as narrow as the connectors will fit in. :grin:
peter d
Senior Member
- Location
- New England
iwire said:
I agree.
C's should be banned from production and use in anything over 3/4"(But I'm just agreeing so I can keep accumulating brownie points.
)
- Location
- Massachusetts
peter d said:I agree.
OK maybe even up to 1". :smile:
(But I'm just agreeing so I can keep accumulating brownie points.
Sorry, the hard drive crashed, all previously awarded Brownie points have been lost. :grin:
peter d
Senior Member
- Location
- New England
iwire said:
Yeah, I suppose a 1" with 10 gauge and under wouldn't be so bad.
iwire said:
I'm going to have to hire a data recovery specialist to retrieve it then. I can't afford to lose that data.
I could not agree more on the LBs. When I was contracting, it didn't take me but a few installatiosn to switch to the "NEC-LB" (Appleton nomenclature, I believe) on larger wire pulls.
When I first started inspecting I was thoroughly disgusted that our AHJ ignored the wire fill on LB's and the advantage of the "mogul" LBs sating "we don't enforce it because no one stocks them" well.. DUH! If we enforced it, they would stock them.
Like Brian, I've seen more wire damge with LBs than any J Box, and like Bob, give me a wireway over a C anytime.
When I first started inspecting I was thoroughly disgusted that our AHJ ignored the wire fill on LB's and the advantage of the "mogul" LBs sating "we don't enforce it because no one stocks them" well.. DUH! If we enforced it, they would stock them.
Like Brian, I've seen more wire damge with LBs than any J Box, and like Bob, give me a wireway over a C anytime.
micromind
Senior Member
- Location
- Fernley, NV. (near Reno)
I use C condulets frequently when the run exceeds 360 deg., and I can pull it in one shot. It complies with code, and pulling straight through one is not an issue at all. I frequently forget to put the covers on, though.
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