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Senior Member
- Location
- Fairmont, WV, USA
Section/Paragraph: Article 366 Auxiliary Gutters
Revised Text
366.1 Scope.
This article covers the use, installation, and construction requirements of metallic auxiliary gutters and nonmetallic auxiliary gutters and associated fittings.
366.2 Definitions.
Auxiliary Gutter.
An enclosure used to supplement wiring spaces at meter centers, distribution centers, switchgear, switchboards, and similar points of wiring systems. The enclosure has hinged or removable covers for housing and protecting electrical 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.
Metallic Metal Auxiliary Gutter.
An auxiliary gutter made of a A sheet metal enclosure. used to supplement wiring spaces at meter centers, distribution centers, switchgear, switchboards, and similar points of wiring systems. The enclosure has hinged or removable covers for housing and protecting electrical 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.
An auxiliary gutter made of a A flame-retardant, nonmetallic enclosure. used to supplement wiring spaces at meter centers, distribution centers, switchgear, switchboards, and similar points of wiring systems. The enclosure has hinged or removable covers for housing and protecting electrical 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.
Substantiation:
The use of "metal[lic] or [a] nonmetallic" indicates that any substance may be used. It does not restrict anything, it is redundant and unnecessary. It should be deleted where ever it is found.
The term auxiliary gutter is used about 30 times in the body of the NEC. There are two references to metal auxiliary gutter with one of those instances meaningful and the other related to the confusion of conductor count and ampacity. The term metallic auxiliary gutter is used only within Article 366. Moving the common elements of Metal Auxiliary Gutter and Nonmetallic Auxiliary Gutter into a new definition of Auxiliary Gutter provides a definition for the 30 references and having simplified definitions of Metal Auxiliary Gutter and Nonmetallic Auxiliary Gutter which highlights the differences between the two types.
366.10 Uses Permitted.
(A) Sheet Metallic Metal Auxiliary Gutters.
(1) Indoor and Outdoor Use.
Sheet metallic Metal auxiliary gutters shall be permitted for indoor and outdoor use.
(2) Wet Locations.
Sheet metallic Metal auxiliary gutters installed in wet locations shall be suitable for such locations.
Substantiation:
Annex B Standard Terms of NEC_StyleManual_2011.pdf specifies a preference for "metal" over "metallic" even when used as an adjective, such as "metal raceway".
366.22 Number of Conductors.
(A) Sheet Metallic Auxiliary Gutters.
The sum of the cross-sectional areas of all contained conductors at any cross section of a sheet metallic an auxiliary gutter shall not exceed 20 percent of the interior cross-sectional area of the sheet metallic auxiliary gutter. The adjustment factors in 310.15(B)(3)(a) shall be applied only where the number of current-carrying conductors, including neutral conductors classified as current-carrying under the provisions of 310.15(B)(5), exceeds 30. Conductors for signaling circuits or controller conductors between a motor and its starter and used only for starting duty shall not be considered as current-carrying conductors.
(B) Nonmetallic Auxiliary Gutters.
The sum of cross-sectional areas of all contained conductors at any cross section of the nonmetallic auxiliary gutter shall not exceed 20 percent of the interior cross-sectional area of the nonmetallic auxiliary gutter.
Substantiation:
The number of conductors allowed within both types of auxiliary gutters is the same. Just state it once.
Unaccountably (historical development of the article perhaps?) restrictions on the ampacity of conductors are under Number of Conductors. Move to Ampacity of Conductors.
366.23 Ampacity of Conductors.
The adjustment factors specified in 310.15(B)(3)(a) shall be applicable to the current-carrying conductors in the auxiliary gutter.
The current carried continuously in bare copper bars in auxiliary gutters shall not exceed 1.55 amperes/mm? (1000 amperes/in.?) of cross section of the conductor. For aluminum bars, the current carried continuously shall not exceed 1.09 amperes/mm? (700 amperes/in.?) of cross section of the conductor.
Conductors for signaling circuits or controller conductors between a motor and its starter and used only for starting duty shall not be considered as current-carrying conductors.
Exception: In a metal auxiliary gutter, the adjustment factors specified in 310.15(B)(3)(a) shall not apply if the number of current carrying conductors does not exceed 30.
(A) Sheet Metallic Auxiliary Gutters.
Where the number of current-carrying conductors contained in the sheet metallic auxiliary gutter is 30 or less, the adjustment factors specified in 310.15(B)(3)(a) shall not apply. The current carried continuously in bare copper bars in sheet metallic auxiliary gutters shall not exceed 1.55 amperes/mm 2 (1000 amperes/in. 2 ) of cross section of the conductor. For aluminum bars, the current carried continuously shall not exceed 1.09 amperes/mm 2 (700 amperes/in. 2 ) of cross section of the conductor.
(B) Nonmetallic Auxiliary Gutters.
The adjustment factors specified in 310.15(B)(3)(a) shall be applicable to the current-carrying conductors in the nonmetallic auxiliary gutter.
Substantiation:
The ampacity of conductors in both types of auxiliary gutters are the same, with one exception for for the first 30 conductors in metal auxiliary gutters. Moving the adjustment factors and capacity of busbars under "Ampacity of Conductors" makes it clear that it applies to both types of auxiliary gutters.
366.30 Securing and Supporting.
(A) Sheet Metallic Metal Auxiliary Gutters.
Sheet metallic Metal auxiliary gutters shall be supported and secured throughout their entire length at intervals not exceeding 1.5 m (5 ft).
366.60 Grounding.
Metallic Metal auxiliary gutters shall be connected to an equipment grounding conductor(s), to an equipment bonding jumper, or to the grounded conductor where permitted or required by 250.92(B)(1) or 250.142.
Substantiation:
Annex B Standard Terms of NEC_StyleManual_2011.pdf specifies a preference for "metal" over "metallic" even when used as an adjective, such as "metal raceway".
Reference repair:
310.15 Ampacities for Conductors Rated 0?2000 Volts.
....
(B) Tables
....
(3) Adjustment Factors.
(a) More Than Three Current-Carrying Conductors.
....
Informational Note No. 2: See 366.23(A) for adjustment factors for conductors and ampacity for bare copper and aluminum bars in sheet metal auxiliary gutters and 376.22(B) for adjustment factors for conductors in metal wireways.
520.6 Number of Conductors in Raceway.
The number of conductors permitted in any metal conduit, rigid nonmetallic conduit as permitted in this article, or electrical metallic tubing for circuits or for remote-control conductors shall not exceed the percentage fill shown in Table 1 of Chapter 9. Where contained within an auxiliary gutter or a wireway, the sum of the cross-sectional areas of all contained conductors at any cross section shall not exceed 20 percent of the interior cross-sectional area of the auxiliary gutter or wireway. The 30-conductor limitation of 366.22 366.23 and 376.22 shall not apply.
Inserted Deleted
Revised Text
366.1 Scope.
This article covers the use, installation, and construction requirements of metallic auxiliary gutters and nonmetallic auxiliary gutters and associated fittings.
366.2 Definitions.
Auxiliary Gutter.
An enclosure used to supplement wiring spaces at meter centers, distribution centers, switchgear, switchboards, and similar points of wiring systems. The enclosure has hinged or removable covers for housing and protecting electrical 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.
Metallic Metal Auxiliary Gutter.
An auxiliary gutter made of a A sheet metal enclosure. used to supplement wiring spaces at meter centers, distribution centers, switchgear, switchboards, and similar points of wiring systems. The enclosure has hinged or removable covers for housing and protecting electrical 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.
An auxiliary gutter made of a A flame-retardant, nonmetallic enclosure. used to supplement wiring spaces at meter centers, distribution centers, switchgear, switchboards, and similar points of wiring systems. The enclosure has hinged or removable covers for housing and protecting electrical 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.
Substantiation:
The use of "metal[lic] or [a] nonmetallic" indicates that any substance may be used. It does not restrict anything, it is redundant and unnecessary. It should be deleted where ever it is found.
The term auxiliary gutter is used about 30 times in the body of the NEC. There are two references to metal auxiliary gutter with one of those instances meaningful and the other related to the confusion of conductor count and ampacity. The term metallic auxiliary gutter is used only within Article 366. Moving the common elements of Metal Auxiliary Gutter and Nonmetallic Auxiliary Gutter into a new definition of Auxiliary Gutter provides a definition for the 30 references and having simplified definitions of Metal Auxiliary Gutter and Nonmetallic Auxiliary Gutter which highlights the differences between the two types.
366.10 Uses Permitted.
(A) Sheet Metallic Metal Auxiliary Gutters.
(1) Indoor and Outdoor Use.
Sheet metallic Metal auxiliary gutters shall be permitted for indoor and outdoor use.
(2) Wet Locations.
Sheet metallic Metal auxiliary gutters installed in wet locations shall be suitable for such locations.
Substantiation:
Annex B Standard Terms of NEC_StyleManual_2011.pdf specifies a preference for "metal" over "metallic" even when used as an adjective, such as "metal raceway".
366.22 Number of Conductors.
(A) Sheet Metallic Auxiliary Gutters.
The sum of the cross-sectional areas of all contained conductors at any cross section of a sheet metallic an auxiliary gutter shall not exceed 20 percent of the interior cross-sectional area of the sheet metallic auxiliary gutter. The adjustment factors in 310.15(B)(3)(a) shall be applied only where the number of current-carrying conductors, including neutral conductors classified as current-carrying under the provisions of 310.15(B)(5), exceeds 30. Conductors for signaling circuits or controller conductors between a motor and its starter and used only for starting duty shall not be considered as current-carrying conductors.
(B) Nonmetallic Auxiliary Gutters.
The sum of cross-sectional areas of all contained conductors at any cross section of the nonmetallic auxiliary gutter shall not exceed 20 percent of the interior cross-sectional area of the nonmetallic auxiliary gutter.
Substantiation:
The number of conductors allowed within both types of auxiliary gutters is the same. Just state it once.
Unaccountably (historical development of the article perhaps?) restrictions on the ampacity of conductors are under Number of Conductors. Move to Ampacity of Conductors.
366.23 Ampacity of Conductors.
The adjustment factors specified in 310.15(B)(3)(a) shall be applicable to the current-carrying conductors in the auxiliary gutter.
The current carried continuously in bare copper bars in auxiliary gutters shall not exceed 1.55 amperes/mm? (1000 amperes/in.?) of cross section of the conductor. For aluminum bars, the current carried continuously shall not exceed 1.09 amperes/mm? (700 amperes/in.?) of cross section of the conductor.
Conductors for signaling circuits or controller conductors between a motor and its starter and used only for starting duty shall not be considered as current-carrying conductors.
Exception: In a metal auxiliary gutter, the adjustment factors specified in 310.15(B)(3)(a) shall not apply if the number of current carrying conductors does not exceed 30.
(A) Sheet Metallic Auxiliary Gutters.
Where the number of current-carrying conductors contained in the sheet metallic auxiliary gutter is 30 or less, the adjustment factors specified in 310.15(B)(3)(a) shall not apply. The current carried continuously in bare copper bars in sheet metallic auxiliary gutters shall not exceed 1.55 amperes/mm 2 (1000 amperes/in. 2 ) of cross section of the conductor. For aluminum bars, the current carried continuously shall not exceed 1.09 amperes/mm 2 (700 amperes/in. 2 ) of cross section of the conductor.
(B) Nonmetallic Auxiliary Gutters.
The adjustment factors specified in 310.15(B)(3)(a) shall be applicable to the current-carrying conductors in the nonmetallic auxiliary gutter.
Substantiation:
The ampacity of conductors in both types of auxiliary gutters are the same, with one exception for for the first 30 conductors in metal auxiliary gutters. Moving the adjustment factors and capacity of busbars under "Ampacity of Conductors" makes it clear that it applies to both types of auxiliary gutters.
366.30 Securing and Supporting.
(A) Sheet Metallic Metal Auxiliary Gutters.
Sheet metallic Metal auxiliary gutters shall be supported and secured throughout their entire length at intervals not exceeding 1.5 m (5 ft).
366.60 Grounding.
Metallic Metal auxiliary gutters shall be connected to an equipment grounding conductor(s), to an equipment bonding jumper, or to the grounded conductor where permitted or required by 250.92(B)(1) or 250.142.
Substantiation:
Annex B Standard Terms of NEC_StyleManual_2011.pdf specifies a preference for "metal" over "metallic" even when used as an adjective, such as "metal raceway".
Reference repair:
310.15 Ampacities for Conductors Rated 0?2000 Volts.
....
(B) Tables
....
(3) Adjustment Factors.
(a) More Than Three Current-Carrying Conductors.
....
Informational Note No. 2: See 366.23(A) for adjustment factors for conductors and ampacity for bare copper and aluminum bars in sheet metal auxiliary gutters and 376.22(B) for adjustment factors for conductors in metal wireways.
520.6 Number of Conductors in Raceway.
The number of conductors permitted in any metal conduit, rigid nonmetallic conduit as permitted in this article, or electrical metallic tubing for circuits or for remote-control conductors shall not exceed the percentage fill shown in Table 1 of Chapter 9. Where contained within an auxiliary gutter or a wireway, the sum of the cross-sectional areas of all contained conductors at any cross section shall not exceed 20 percent of the interior cross-sectional area of the auxiliary gutter or wireway. The 30-conductor limitation of 366.22 366.23 and 376.22 shall not apply.
Inserted Deleted