ECN Forum Forums Code Related Discussion NEC & other Code issues Oversize LB's??

Yes, the former not. If the conductors are passing through, as with a box, then they are not counted in the fill. The volume is only a concern if there are splices in the LB. Otherwise, no LB is big enough.

As noted here, https://www.electrical-contractor.net/ubb/Forum4/HTML/000166.html splices can only be made if the cubic inch capacity is marked on the box, which lends me to believe that the cubic inch capacity is unimportant if there are no splices.

This, is of course given that the condulet is the same trade size as the properly sized conduit that one is using, and that one isn't using say, a 1/2" LB for 3 3/0's adapted to 2" pipe.

If I'm wrong, please say so. If I may be on the right track, please say so. If I'm out in left field, please say so.

Sparky,
The opening in the conduit body must be large enough to get the conducotrs in and out without damage. This means that in many cases a "mogul" or oversized conduit body must be used. You cannot just assume that a conduit body that is the same size as the conduit is suitable for the largest wires that the wirefill tables permit in the conduit. The opening in the conduit body must comply with 314.28. If the maximum wire size is marked on the fitting, 314.28(A)(3) will permit a smaller opening than that required by 314.28(A) & (B). If the size is not marked on the fitting 314.28(A) and (B) apply to the opening in the conduit body.
Don

[This message has been edited by resqcapt19 (edited 11-06-2002).]

After ranting for several pages, and hitting the "clear fields" button afterwards...

All I can say is:

Cripes! How do y'all make a profit?

No offense, Don, but if some of you guys came down and started looking at some of the electrical work around here, you'd fall to your knees in despair and cry out to God, and then gouge your own eyes out after seeing the horrors that I've seen.

I'd take more pictures, but I don't know what to look for. Heck, I guess every LB is suspect now...

I'm ranting again... Sorry.

Could someone clear up 314.23 E for me please. I`m reading that in E you have to suport 3' or 18" if same side.Got that but the exception. I`m saying ok I don`t have to support if conduit body same as trade entering.But why can`t I go up a size and bush it down provided I do support it.I just don`t see it being a problem with mechanics or electrical issues.Again learning everytime I visit here.Thanks in advance.

I can't believe I've caught myself relying on manufacturers knowing what their doing...

I mean, why wouldn't they make 'em big enough for the conductors likely to be used in the pipe its made for?

I haven't checked out any of the Sceptor LB's I use, but I'm suspicious I've got a lot of recent and in-the-works jobs that have undersized LBs...

Don, et al.
Didn't me to sound mad at ya... I'm really mad at myself. Just when I start getting a big head, I need humbled every now and then...

Don, you hiy the nail on the head....
Try folding 4-3/0 THHN Cu in a 2" "regular LB".. Get out the big hammer and the 2x4.

John

Roller:
I know there is a big cost diff with the mogul vs reg fittings. And you're right about who wins the job most of the time.

And, when the AHJ hangs a red tag, who eats the cost to re-do it?? And if it's a tight schedule job??? And who looks bad???

Ya get what you pay for.

My thing is do it right the first time. Not saying that you can't stuff the conductors in the regular LB, lord knows we have all "done it" at least once. (Tell the truth now guys) Hammer and 2x4. I find a few hammer specials doing retrofit work, and inspections.

BTW: If the prices you quoted are Red Dot, get a $$ on OZGedney or Appleton!!!

John

[This message has been edited by HotLine1 (edited 11-06-2002).]

Yellow77, Cursing, and a few bloody knuckles has always worked for me...



This is gonna eat me up until I get to the job sight tomorrow and take a look at my LBs.

Man...

I'm not aware of any jobs that have been red-tagged because there was say, a 2" LB on 2" EMT, but point well taken. Now, would the following installation be red-tagged: 4- #1 THHN in 1-1/2" EMT. I believe it works out to occupy MORE volume than 3- #1/0 (which IS permitted). I would love to know how many AHJ's are even aware of this. Some more background on this: Evidently a feeder at this establishment (not installed by us, whew!)blew up at the LB. Wire must have been nicked, and eventually found it's way to ground. It was suppposed to have passed the megger test, but eventually failed in spite of this. So, that's how this was all brought up. The new rule there now, is that an engineer must witness all megger testing, in addition to filing a report. For the record, I'm in agreement that a longer LB will make life a lot easier for pulling large diamter cable, and greatly reduce the instance of nicking the wire or chafing the nylon. Also, I've never tried to install wires with a 2 x 4. Years ago I remember skinning UF cable using a piece of PVC to try to shove it in the ground!

In the 1968 NEC the wire fill for conduit was 25% fpr new work and 40% for old work. UL used the 25% fill when investigating certain cast fittings. In 19781 the NEC went to 40% fill for both new and old work, but nobody noticed that the UL listing for these cast fittings was still based on 25% fill until the 1996 NEC. For a time it was proper to use an oversize conduit fitting with reducing bushings, but now most of the manufaturers are making fittings based on the same 40% fill as the trade size conduit