fmtjfw
Senior Member
- Location
- Fairmont, WV, USA
I'm looking for constructive criticism on the following, and if you think it is merited, support in the form of comments from you on 8-96. Thanks, Jim Williams
4 Comment:
Revise the text as follows:
red indicates deleted text.
366.22 Number of Conductors.
(A) Sheet Metal Auxiliary Gutters. The sum of the cross-sectional areas of all contained conductors at any cross section of a sheet metal an auxiliary gutter shall not exceed 20 percent of the interior cross-sectional area of the sheet metal 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.
366.23 Ampacity of Conductors.
The current carried continuously in bare copper bars in auxiliary gutters shall not exceed 1.55 amperes/mm2 (1000 amperes/in.2) of cross section of the conductor. For aluminum bars, the current carried continuously shall not exceed 1.09 amperes/mm2 (700 amperes/in.2) of cross section of the conductor.
(A) Sheet Metal Auxiliary Gutters. Where the number of current-carrying conductors contained in the sheet metal auxiliary gutter is 30 or less, the adjustment factors specified in 310.15(B)(3)(a) shall not apply. 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. The current carried continuously in bare copper bars in sheet metal auxiliary gutters shall not exceed 1.55 amperes/mm2 (1000 amperes/in.2) of cross section of the conductor. For aluminum bars, the current carried continuously shall not exceed 1.09 amperes/mm2 (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.
5 Statement of Problem and Substantiation.
1: With the removal of the ampacity text in 366.22, (A) and (B) are essentially duplicate text and can be merged into a single sentence under 366.22 directly. (as is done 366.44 through 366.58 for example).
2: The ampacity rules for sheet metal auxiliary gutters are presently contained in 366.22 (which is labeled ?Number of Conductors? and in 366.23(A). Further the rules differ in detail and could easily lead others into confusion (as it has for me).
3: The definitions for sheet metal and nonmetallic auxiliary gutters both reference bus bars, but the busbar ampacities in the original text only appear under sheet metal auxiliary gutters. Moving that information directly under 366.23 solves that problem.
Combining the ampacity rules in a single place for sheet metal auxiliary gutters and especially in a place labeled ?Ampacity of Conductors? leads to the easier correct application of the NEC. Placing the busbar ampacity directly in 366.23 makes it easier to find for nonmetallic auxiliary gutters.
4 Comment:
Revise the text as follows:
red indicates deleted text.
366.22 Number of Conductors.
(A) Sheet Metal Auxiliary Gutters. The sum of the cross-sectional areas of all contained conductors at any cross section of a sheet metal an auxiliary gutter shall not exceed 20 percent of the interior cross-sectional area of the sheet metal 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.
366.23 Ampacity of Conductors.
The current carried continuously in bare copper bars in auxiliary gutters shall not exceed 1.55 amperes/mm2 (1000 amperes/in.2) of cross section of the conductor. For aluminum bars, the current carried continuously shall not exceed 1.09 amperes/mm2 (700 amperes/in.2) of cross section of the conductor.
(A) Sheet Metal Auxiliary Gutters. Where the number of current-carrying conductors contained in the sheet metal auxiliary gutter is 30 or less, the adjustment factors specified in 310.15(B)(3)(a) shall not apply. 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. The current carried continuously in bare copper bars in sheet metal auxiliary gutters shall not exceed 1.55 amperes/mm2 (1000 amperes/in.2) of cross section of the conductor. For aluminum bars, the current carried continuously shall not exceed 1.09 amperes/mm2 (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.
5 Statement of Problem and Substantiation.
1: With the removal of the ampacity text in 366.22, (A) and (B) are essentially duplicate text and can be merged into a single sentence under 366.22 directly. (as is done 366.44 through 366.58 for example).
2: The ampacity rules for sheet metal auxiliary gutters are presently contained in 366.22 (which is labeled ?Number of Conductors? and in 366.23(A). Further the rules differ in detail and could easily lead others into confusion (as it has for me).
3: The definitions for sheet metal and nonmetallic auxiliary gutters both reference bus bars, but the busbar ampacities in the original text only appear under sheet metal auxiliary gutters. Moving that information directly under 366.23 solves that problem.
Combining the ampacity rules in a single place for sheet metal auxiliary gutters and especially in a place labeled ?Ampacity of Conductors? leads to the easier correct application of the NEC. Placing the busbar ampacity directly in 366.23 makes it easier to find for nonmetallic auxiliary gutters.