Gutter Size Dillema

[innersurffer]

A trough was sent out to me for the pupose of a pass thruough gutter that would have 2 - 2" coudutits on the topside and approx. 4- 2" couduits on the bottom side. The topside is the feeds off of a meter bank and the bottom side are the feeds out to the individual units in a warehouse. The box has been sized 10" X 10" x 4'
( H x W X L) The couduits from the are on the 10" side. Isn't the calculations supposed to be taken from the side the couduits go into and applied on the that side and for straight pass through be at a multiple of 8 times? The box should be 18" X 18" X 4' shouldn't it? Or is there some alternate box method I am not aware of? My head estimator is using a 1999 code book. Would that make a difference? And how do I share "politely" this information? :roll:

 

[bphgravity]

Re: Gutter Size Dillema

I would consider this installation as more of an "Auxiliary Gutter" as opposed to a "Pull Box". That being said , I feel the requirements in Article 366 apply. (366.6)

 

[BAHTAH]

Re: Gutter Size Dillema

Because the gutter is not physically connected to the metering equipment I would not consider it an auxiliary gutter. From your question it appears you have multi feeds in the (2) 2" conduits that enter the gutter and then exit through the (4) 2" conduits going to the various units. Metal wireways are covered in Article 362 of the 1999 NEC that you are using. 362-6 covers the deflection of conductors within a wireway and would require at least 6" between raceways containing the same conductors. In addition if the deflection is greater than 30-degrees you would need to look at Article 373-6.

 

[bphgravity]

Re: Gutter Size Dillema

Originally posted by grant:
Because the gutter is not physically connected to the metering equipment I would not consider it an auxiliary gutter.

Please explain this statement. What indicates something is a wireway opposed to an auxiliary gutter?

 

[BAHTAH]

Re: Gutter Size Dillema

If you look at Article 376 of the 2002 (don't have the 1999 code with me now), you will see the definition of Metal Wireways. Auxiliary Gutters are the same construction as Wireways but are different in their use. Auxiliary gutters are limited in that they can only be run a maximum of 30ft from a panel for example in most cases. Wireways in Article 376 can be run any distance. Auxiliary gutters are extensions of metering equipment, distribution panels, switchboards etc and are covered under Article 366. Because in this question the installer ran conduit from the metering equipment to the Wireway, in my opinion this is not the type of extension use described in Article 366 and the wireway would not be limited in how far it could be run. Because there would be no limit on the conduit run from the metering equipment to the wireway I would have a problem if the wireway were 50ft away and someone wanted to call it an Auxiliary Gutter. Thats just my opinion, hope it helps.

 

[innersurffer]

Re: Gutter Size Dillema

Thanks for all the great answers. I guess I was incorrect in thinking to use this as a Jct. Box situation (using 8 times the multiplier for an in and out feeder to a meter bank) and should use the 20% rule and 30% wire bending rule everyone is pointing to. It has been very enlightening. If anyone has something further to add to help me see the differences of using the j-box sizing requirements (8 X the trade designator) vs gutter sizing (20-30% wire fill rules including angles of deflection) for underneath this meter bank it would be greatly appreciated.