So a job that I'm on has the power running in the slab. All the conduits come into a 6x6 trough from the top level then the go out of the bottom of the trough under the slab on the lower level (in independent conduits with not more that 3 circuits) to another 6x6 trough mounted underneath three panels. Then there are two 2" conduits going from the trough to each panel. Do I have to derate the number 12 wire??
Metallic auxiliary gutter fill
- Thread starter Blbracer
- Start date
- Status
kwired
Electron manager
- Location
- NE Nebraska
376.22(B).
only need to apply adjustments if number of current carrying conductors at any cross section exceeds 30.
24 inch nipple rule applies to the two 2" conduits running from wireway to the panel and those wouldn't need adjustment as long as they are not over 24 inches.
only need to apply adjustments if number of current carrying conductors at any cross section exceeds 30.
24 inch nipple rule applies to the two 2" conduits running from wireway to the panel and those wouldn't need adjustment as long as they are not over 24 inches.
So if I have 30 conductors I'm good but if I put 32 conductors the I have to use the adjustment table which then starts out at 80% for 4-6 conductors and then so on based off table 310.15(B) (3) (a)
- Location
- New Jersey
- Occupation
- Journeyman Electrician
The derating kicks in at more than 30 CCC's at any cross section of the raceway. This is a wireway or an auxiliary gutter?
To me it would be considered a auxiliary gutter.
kwired
Electron manager
- Location
- NE Nebraska
Remember it says at one cross section.
If you have 60 conductors entering via a nipple from a panelboard 30 could go left and 30 could go right and no ampacity adjustments needed.
this 30 conductor rule also applies to aux gutters so doesn't matter whether it is called a wireway or aux gutter. There is little difference between the two and same piece of equipment could be used as either. Definitions mostly state an aux gutter is used to facilitate installations of multiple cabinets or other enclosures grouped together where a wireway maybe is more of a method of getting conductors to a destination not quite so close together.
Add dividers in the trough does that make it two wireways
kwired
Electron manager
- Location
- NE Nebraska
Probably so. If doing it lengthwise it reduces cross sectional area of each "wireway" and reduces how much conductor you can fill it with as well though.
Most time this is done to separate service and non service conductors or class 2 and 3 control wiring from class 1 and/or power wiring. Kind of common AFAIK with medical imaging equipment or similar.
- Location
- New Jersey
- Occupation
- Journeyman Electrician
Where is that in the NEC?
kwired
Electron manager
- Location
- NE Nebraska
Think he was the one asking if it is possible. But at same time where does it prohibit calling such setup two wireways?
What do you have if you would place two separate wireways next to one another with virtually no space between them? Still two or is it one?
As I mentioned if you put a divider in one you at very least created two with smaller cross sections than the original which will lessen how much fill is allowed per section, yet still allows same net fill (disregarding the space the divider itself consumes).
- Location
- Illinois
- Occupation
- retired electrician
Auxiliary gutters are rare. They only exist where they extend the space within another piece of equipment, and are typically an optional accessory supplied by the equipment manufacturer. If the item in question is connected to the other equipment via raceways, it is a wireway and not an auxiliary gutter.
If you have more than 30 current carrying conductors at a cross section, take a look at 310.15(A)(2) Exception in the 2017 code or 310.14(A)(2) Exception in the 2020.
Strathead
Senior Member
- Location
- Ocala, Florida, USA
- Occupation
- Electrician/Estimator/Project Manager/Superintendent
What gets me is, that this is a violation of 314.28 or more specifically the requirement 366.58 (B) which i see violated all the time.
kwired
Electron manager
- Location
- NE Nebraska
If conductors are 4 AWG or larger.
I think OP was asking about a wireway containing mostly if not exclusively 12 AWG conductors
Yes all #12 wire
Sorry that was supposed to be a question
- Location
- New Jersey
- Occupation
- Journeyman Electrician
Ah that makes sense. We've discussed that topic before and IMO a barrier does not allow you to double the number of CCC's before derating. The NEC specifically says that a barrier in a box makes that into two separate boxes but there is no such wording for a wireway. IMO there should be.
Fiddling Fiddler
Member
- Location
- Wyoming
Can someone define the term cross section ?
Strathead
Senior Member
- Location
- Ocala, Florida, USA
- Occupation
- Electrician/Estimator/Project Manager/Superintendent
a two dimensional plane made by imagining a cutting the wireway at a 90 degree angle
Dsg319
Senior Member
- Location
- West Virginia
- Occupation
- Wv Master “lectrician”
- Location
- Illinois
- Occupation
- retired electrician
The area shown in A is not a cross-sectional area for any code purpose related to wireways.
- Status