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