Gutter/wireway/pullbox sizing

[Rich D]

After searching the forums for a while i wasn't able to come up with an answer to my questions regarding gutter vs pull boxes vs wireways.
My confusion is when does an auxilly gutter become a pull box, what defines a pull box? When sizing a pull box by 314.28 the size would have to be so large it would be very impracticle, assuming the conductors are #4 or larger and the conduits are 2.5".
Why cant, or can i, use a gutter sized according to 1 wire per terminal, instead of using the 2.5" conduit at 6x + the sum of all others on the same wall. If i required a gutter with 3 2.5" nipples and 3 1 1/4" nipples leaving one wall by 314.28 it would have to be 26 3/4" wide.
a little help would be greatly appreciated.

 

[augie47]

To me, the key word is "pull". If you look at definition of an auxiliary gutter in Art 366 it notes being designed for conductors to be laid or set in place.
You can search previous threads on Art 376 and see there are varying opinions as to the exact requirement of the "6X" measurement with wireways.

 

[cpal]

After searching the forums for a while i wasn't able to come up with an answer to my questions regarding gutter vs pull boxes vs wireways.
My confusion is when does an auxilly gutter become a pull box, what defines a pull box? .

366.58 Insulated Conductors.
(A) Deflected Insulated Conductors. Where insulated conductors are deflected within an auxiliary gutter, either at the ends or where conduits, fittings, or other raceways or cables enter or leave the gutter, or where the direction of the gutter is deflected greater than 30 degrees, dimensions corresponding to one wire per terminal in Table 312.6(A) shall apply.
Conductors are also required to be shaped or formed in a permanent manner so that they are not in contact with bare busbars within the gutter.
(B) Auxiliary Gutters Used as Pull Boxes. Where insulated conductors 4 AWG or larger are pulled through an auxiliary gutter, the distance between raceway and cable entries enclosing the same conductor shall not be less than that required in 314.28(A)(1) for straight pulls and 314.28(A)(2) for angle pulls.


the same applies to wireways


Check out 314.28

 

[Rich D]

This still does not seem to make much sense. If i require a trough that will have 3 1 1/4" conduits and 3 1 1/2" conduits on 1 wall it will have to be 15.25" wide if it contains conductors of #4 or greater, even if the trough is 36" in length. I could move into a trough that large.