Wireway vs aux. gutter

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Dennis Alwon

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Can someone explain what the difference is between a metal wireway (376) and a metal auxiliary gutter (366). I see aux. gutters seem to involve services but what is the physical difference and if you can give an example that would be good. Someone has asked this question and I really don't know the answer.
 

dkidd

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(Log #1605)
4-30- (230-7, Exception No. 3): Accept
SUBMITTER: Larry F. Miller, National Electrical Mfrs. Association
COMMENT ON PROPOSAL NO: 4-49
RECOMMENDATION: The Panel should continue to Reject the
proposal, but should further clarify the Panel Statement.
SUBSTANTIATION: The Panel is correct in their action on this
proposal on the basis that the application referenced by the
submitter is not an auxiliary gutter. Auxiliary gutters are intended as
supplemental space to a piece of equipment. The six separate
disconnects, as given in the submitter's example are not a piece of
equipment, they are six pieces of equipment. The application noted
by the submitter is in reality a normal application of a wireway.
The Panel Statement should be clarified because some properly
used auxiliary gutters may contain both service and nonservice
conductors. An example of this is an auxiliary gutter supplementing
the space of a panelboard used as service equipment. Depending on
the arrangement, the auxiliary gutter may in fact contain both
conductor types and this could be construed as incorrect based on
the present Panel Statement.
PANEL ACTION: Accept.
PANEL STATEMENT: Auxiliary gutters may be used as extensions
of the wiring space of service equipment when designed by the
manufacturer as such. Auxiliary gutters may not be used to connect
multiple pieces of service equipment together.
NUMBER OF PANEL MEMBERS ELIGIBLE TO VOTE: 12
VOTE ON PANEL ACTION: AFFIRMATIVE: 11
NOT RETURNED: Veazey
 

dkidd

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________________________________________________________________
8-124 Log #3403 NEC-P08 Final Action: Accept
(366.2)
________________________________________________________________
Submitter: Frederic P. Hartwell, Hartwell Electrical Services, Inc.
Recommendation: Revise as follows:
366.2 Definitions
Metallic Auxiliary Gutter. A sheet metal enclosure used to supplement wiring
spaces at meter centers, distribution centers, switchboards, and similar points of
wiring systems. The enclosure has hinged or removable covers for housing and
protecting electric wires, cable and busbars. The enclosure is designed for
conductors to be laid or set in place after the enclosures have been installed as
a complete system.
Nonmetallic Auxiliary Gutter. A flame retardant, nonmetallic enclosure used
to supplement wiring spaces at meter centers, distribution centers,
switchboards, and similar points of wiring systems. The enclosure has hinged
or removable covers for housing and protecting electric wires, cable and
busbars. The enclosure is designed for conductors to be laid or set in place after
the enclosures have been installed as a complete system.
Delete the parent text of 366.10, leaving only the title (?Uses Permitted?).
Substantiation: The present NEC text complicates one of the most difficult
tasks for NEC trainers within the scope of CMP 8, namely, explaining the
difference between auxiliary gutters and wireways. This is especially true given
that the equipment used is always listed for both functions, and only the
applicable field usage divides the two articles. Since the usage defines the
article application, it is essential that the definitions at the beginning of the
article focus on on this point.
This proposal includes the usage information now appearing in 366.10 in the
definitions for this reason. This proposal also carefully excludes from the
definitions any use of the word ?wireway? which really confuses one from the
other. This proposal does not change any code rules, but presents the
information in a far more understandable format. The syntax has also been
changed so it works purely as two definitions.
Panel Meeting Action: Accept
Number Eligible to Vote: 12
Ballot Results: Affirmative: 12
 

Dennis Alwon

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Staff member
Location
Chapel Hill, NC
Occupation
Retired Electrical Contractor
So basically an aux gutter is built into the equipment and a wireway is a separate piece of equipment. :thumbsup: Yes?
 

dkidd

Senior Member
Location
here
Occupation
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Since a gutter is "used to supplement wiring spaces" it indicates that it is open to the associated equipment. A wireway would be connected by raceways or fittings.
 

iwire

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Location
Massachusetts
I think checking the listing sticker could be sure fire way to know what you are dealing with.

I don't think I have ever seen an auxiliary gutter. :)
 
http://ulstandardsinfonet.ul.com/scopes/scopes.asp?fn=0870.html

Here is the UL listing for wireways/auxiliary gutters.

There is no physical difference between the two. Both are made of exactly the same material, etc.... It is the placement of where they are installed that determines which they would be called, and what can be installed within the enclosure.

Art 366 (2014) -

.2 Definition - basically tells us that the enclosure is there to support the wiring for said equipment (meter enclosures, switchgear, panelboards, etc...)

.6 - Listing - I only see that Nonmetallic type gutters are required to be listed in regards to the NEC. ***There are some auxiliary gutters listed on the market, but not all are listed.

.12 -
tells us what is not permitted to be installed the auxiliary gutters.
It also tells us another important factor of gutters - that they cannot be installed more than 30 feet beyond the equipment they are supplementing.


These are the differences between Art 366 and Art 376. Otherwise they are very similar. You would order the exact same material for either, it is the placement in "feet" that determines which Article to reference for installation.
*** there is no listing requirement in Art 376 for metal wireways.



The question that arises in the field in distinguishing between the two is:

" If I have a wireway in a large mechanical room that is continuous for more than 30 feet, can the first 30 feet be an Auxiliary Gutter following Art 366? Can the rest of the continuous Metal Wireway be considered as Metal Wireway and follow the requirements of Art 376?"
 
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