L.B. Capacity

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mayor43822

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Have a 2" PVC conduit L.B. with a cubic in. rating of 66 cu. in. need to
install a 4/0 SER cable into L.B and need to calculate cu.in. of wires to
be at the 66 cu.in. or under . Cable has three 4/0 and one 2/0 bare .
 
Why are you calculating cubic inch fill for wires sized #4 and larger? In the bigger sizes, you need to look at what is stamped on the LB for number and size of wires allowed. It may say "(3) 250" or something like that. The quandry is when you have 4 wires and it lists 3 that are larger than the 4 you have. Best to consult the manufacturer's data for fill.

The SER throws a wrench into this too. Are you stripping the jacket once it enters the LB? How far do you need to go past the LB with the conductors that have a stripped jacket?

I think you may have a problem with 4/0 SER in a 2" LB. The only other way to get permissible fill for a condulet is by using the wall distance based on pipe diameter rules. But most condulets don't have enough distance to the opposite wall unless you go up a few sizes and install reducers (or use the Mogul type LB's).
 
there is no getting that cable to make the turn. you are going to have to strip them. hope you got conduit on the other side. i use this one on a regular basis. how do you get around 3 wires in an lb? buy one that doesnt have that marking just the cubes. better yet buy 50 of them cause they will quit making anything thats any good for any one under our current federal administration.
 
The "no more than 3 conductors of such&such size" is a cross sectional area maximum for the wires allowed in the condulet. Any combination of smaller wires that are equal to or less than that number should be fine.
 
btharmy said:
The "no more than 3 conductors of such&such size" is a cross sectional area maximum for the wires allowed in the condulet. Any combination of smaller wires that are equal to or less than that number should be fine.
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and you can support that by what Code section ?
 
314.28(A)(3) gives no provision for "calculated cross sectional area". It states 6X or maximum number of conductors as marked.
 
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