When can I use a gutter vs junction box?

[marmathsen]

I have very little experience with installing gutters.

Based on what I'm reading in the NEC and some EC&M articles, I feel like I'm missing something that allows the use of gutters in more applications. A lot of articles and NEC handbook drawings show horizontal gutters with conduits entering from the top and the bottom. But 314.28 states:

“In straight pulls, the length of the box or conduit body shall not be less than eight times the metric designator (trade size) of the largest raceway”. So if those conduits are 2” then the gutter would need to be 16” tall right?

So if those conduits are 2” then the gutter would need to be 16” tall right?

This is an example from the handbook



In the image below I had planned to use a gutter underneath this meter/ATS. I assumed I could run (almost) all these conduits (5 x 1.5", 2 x 3/4") into the bottom of this gutter, then have two conduits (2 x 2") feeding out the back into the panel behind, and one conduit (1 x 1.5") feeding up into the ATS/meter with the generator conductors. But in looking at 314.28 I need a 16.5" tall box. Or am I missing something that would allow less height? Similarly, on the other side of this wall, I wanted to use a gutter that has 2 conduits in the back (2 x 2") of it and 2 on the top (2 x 2"), which by my math needs to be 14" tall.

 

[jaggedben]

I think what you're missing is that the proper term for what we commonly call a 'gutter' is a wireway. Which means they're covered by article 376, not 314. And while 376.23(B) refers back to 314, it only does so for the distance between raceway entrys containing the same conductors, not for the dimensions of the wireway. So for example as long as your 1.5" conduit entries for the same conductors can be 9" apart from each other, you can do this legitimately with a gutter.

 

[augie47]

Agree with jaggedben but am curious as to why you have 5 1-1/2: conduits ??

 

[marmathsen]

Agree with jaggedben but am curious as to why you have 5 1-1/2: conduits ??

26kw generator
Sub-panel (existing)
Outbuilding
Water GEC (3/4)
The rest are future because the scope changes about every 10 minutes

This is mounted on a garage. The conduits all run through the ground about 10 feet to the right where they go under the foundation into the crawl space.

Rob G - Seattle

 

[darekelec]

If you rotate wireway so the cover is opposite entry of conduits then you don’t need 8x hight of wireway.

 

[PaulEd]

I think what you're missing is that the proper term for what we commonly call a 'gutter' is a wireway. Which means they're covered by article 376, not 314. And while 376.23(B) refers back to 314, it only does so for the distance between raceway entrys containing the same conductors, not for the dimensions of the wireway. So for example as long as your 1.5" conduit entries for the same conductors can be 9" apart from each other, you can do this legitimately with a gutter.

If you rotate wireway so the cover is opposite entry of conduits then you don’t need 8x hight of wireway.

Forgive my ignorance but I don't understand this rule.

Jaggedben where are you coming up with 9" apart for a 1.5" conduit? Also are you saying because the conductors aren't going through the "gutter" or trough and because they are going to be spliced within the box with other conductors (for whatever reason) then 314's rules of 6x's and 8x's don't apply?

Darekelec can you be a little more specific in reference to your comment?

Paul

 

[jaggedben]

...

Jaggedben where are you coming up with 9" apart for a 1.5" conduit?

1.5" × 6 = 9"

Also are you saying because the conductors aren't going through the "gutter" or trough and because they are going to be spliced within the box with other conductors (for whatever reason) then 314's rules of 6x's and 8x's don't apply?

The 6× and 8× rules apply to the distance between conduit entries within the wireway that contain the unspliced conductors, but they don't apply to the size of the wireway.

 

[darekelec]

Wireway is also a pullbox and must satisfy pullbox rules .

I am recommending to use this rule

Removable covers​

When conductors enter an enclosure with a removable cover (e.g., conduit body, handhole enclosure, or wireway), the distance from the removable cover to where the conductors enter must not be less than the bending distance listed in Table 312.6(A), based on one conductor per terminal.

Full article is

Sizing Junction Boxes

Learn how to perform this task quickly and correctly — every time

www.ecmweb.com

 

[jaggedben]

Wireway is also a pullbox and must satisfy pullbox rules .

...

I disagree. A wireway is a wireway and is covered by article 376 (or 378). Articles 312 and 314 do not apply (except for those sections specifically mentioned in 376 or 378).

 

[electrofelon]

I disagree. A wireway is a wireway and is covered by article 376 (or 378). Articles 312 and 314 do not apply (except for those sections specifically mentioned in 376 or 378).

Don't have the book in front of me, but isn't there some wording in 376 about wire ways used as pull boxes?

 

[jaggedben]

Don't have the book in front of me, but isn't there some wording in 376 about wire ways used as pull boxes?

Yes, but it only refers to certain sections of 314.

 

[darekelec]

376.23 Insulated Conductors. Insulated conductors in- stalled in a metallic wireway shall comply with 376.23(A) and (B).

(B) Metallic Wireways Used as Pull Boxes. Where insu- lated conductors 4 AWG or larger are pulled through a wire- way, the distance between raceway and cable entries enclosing the same conductor shall not be less than that required by 314.28(A)(1) for straight pulls and 314.28(A)(2) for angle pulls. When transposing cable size into raceway size, the mini- mum metric designator (trade size) raceway required for the number and size of conductors in the cable shall be used.

From 2008 nec

 

[jaggedben]

Right. But there are many other rules in 314 that wireway installations don't have to follow.

 

[darekelec]

I disagree. A wireway is a wireway and is covered by article 376 (or 378). Articles 312 and 314 do not apply (except for those sections specifically mentioned in 376 or 378).

Do you agree now?

 

[jaggedben]

Do you agree now?

That a wireway is a pullbox? No.

 

[augie47]

My thinking is in agreement with jaggedben (post#2) but it looks like you might have trouble maintaining the 6" distance between raceways. The 20" pullbox might be your only option

 

[darekelec]

When wire way is used as a pull box then it must follow pullbox rules says Mike Holt.
My understanding is you guys do not agree with this statement.

 

[wwhitney]

When wire way is used as a pull box then it must follow pullbox rules says Mike Holt.

No, the graphic refers to one specific wireway rule (376.23(B)) that says in the situation described therein, you have to follow one particular pull box rule (314.28(A)(1) or 314.28(A)(2)). But it doesn't say, nor is it true, that a wireway used as a pull box must comply with all the pull box rules.

Cheers, Wayne

 

[jaggedben]

If that graphic is trying to claim that the wireway needs to be 14" tall I just disagree. 376 simply does not say that rule applies. I don't care if it's a Mike Holt graphic. (I do note it's old and I don't know if there's been any changes.)