When sizing a gutter and you have conductors larger than #4 and you need to 90 into it how do you go about sizeing it . Gutters have their own section in the code and (from what I can tell) it does not state anywhere to crossreference to 314.71. The only way I can see looking at it right is to rewrite the one line diagram stateing "gutter" and think about it as a "junction box" because there are actual splices in terminal blocks. Does this argument make sense. (shop wants me to pull 2 parallel sets of 3/0 3ph and 90 into an 8 inch wide gutter) any clarification would help.
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Gutter sizeing
- Thread starter nathan1
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bphgravity
Senior Member
- Location
- Florida
Re: Gutter sizeing
I guess you need to determine exactly what you are working with, a gutter or a junction box. The best way to determine is by checking the listing of the enclosure. UL lists auxiliary gutters separate from general pull boxes.
If it is indeed a gutter that you are using, Section 366.6(A) or (B) shall be used for sizing the gutter depending on if the gutter is metallic or not.
If it is not a gutter and just a junction box, than you can use the requirements of section 314.28 for under 600V. 314.71 is for sizing on systems over 600V.
I guess you need to determine exactly what you are working with, a gutter or a junction box. The best way to determine is by checking the listing of the enclosure. UL lists auxiliary gutters separate from general pull boxes.
If it is indeed a gutter that you are using, Section 366.6(A) or (B) shall be used for sizing the gutter depending on if the gutter is metallic or not.
If it is not a gutter and just a junction box, than you can use the requirements of section 314.28 for under 600V. 314.71 is for sizing on systems over 600V.
teamextreme
New member
- Occupation
- Controls Engineer
Re: Gutter sizeing
Dragging up an old post here, but this is exactly the question I am facing. What technically is the difference between a gutter and j-box? The NEC does not define either. I am running 3 400MCM's vertically down a 2.5" pipe into a "gutter" where they will splice on a terminal block to three smaller conductors (each), then continue down vertically through three smaller conduits to the meter bases.
If I consider this a gutter and size using 366.6, it only addresses the cross-sectional area in commparison to the conductors used. No mention of dimentions.
If I consider this to be a junction box and use 314.28, this would be a "straight pull" and my gutter height would have to be 8 times 2.5", or 20"!
Article 312.6 discusses deflection of conductors and seems to be the most applicable. Part A talks to width of gutters and directs you to use table 312.6A, which would require a 6" gutter if I use the 1 wire per terminal column (is this correct?).
So which code section should be followed, and again, what defines a gutter vs. a j-box? Isn't a gutter just a long, skinny j-box, or pull box?
Dragging up an old post here, but this is exactly the question I am facing. What technically is the difference between a gutter and j-box? The NEC does not define either. I am running 3 400MCM's vertically down a 2.5" pipe into a "gutter" where they will splice on a terminal block to three smaller conductors (each), then continue down vertically through three smaller conduits to the meter bases.
If I consider this a gutter and size using 366.6, it only addresses the cross-sectional area in commparison to the conductors used. No mention of dimentions.
If I consider this to be a junction box and use 314.28, this would be a "straight pull" and my gutter height would have to be 8 times 2.5", or 20"!
Article 312.6 discusses deflection of conductors and seems to be the most applicable. Part A talks to width of gutters and directs you to use table 312.6A, which would require a 6" gutter if I use the 1 wire per terminal column (is this correct?).
So which code section should be followed, and again, what defines a gutter vs. a j-box? Isn't a gutter just a long, skinny j-box, or pull box?
izak
Senior Member
- Location
- Springfield, MO
Re: Gutter sizeing
366.2 in the 2002 NEC says:
USE. Auxillary gutters shall be permitted to supplement wiring spaces at Meter Centers, Distribution Centers, Switchboards and similar points of wiring systems and may enclose conductors or busbars or blah blah.... on an on
what it says to me is that if you are using a 'gutter' or 'trough' anywhere else, like somewhere in a conduit run, then you are using a junction box or pull box and not a gutter, regardless of how it is listed.
366.2 in the 2002 NEC says:
USE. Auxillary gutters shall be permitted to supplement wiring spaces at Meter Centers, Distribution Centers, Switchboards and similar points of wiring systems and may enclose conductors or busbars or blah blah.... on an on
what it says to me is that if you are using a 'gutter' or 'trough' anywhere else, like somewhere in a conduit run, then you are using a junction box or pull box and not a gutter, regardless of how it is listed.
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