ROP's for 1990 NEC

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I'm looking for an exception that was added in the 1990 NEC. The exception is still in the 2008 NEC. I'm looking for the intent and substantiation for the exception.

 

[chris kennedy]

An exception to which article?

 

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1990 NEC 310-15 (c) Exception. 2008 NEC 310.15 (A) (2) Exception.

 

[don_resqcapt19]

[FONT=&quot]log [/FONT][FONT=&quot]#[/FONT][FONT=&quot]2999 [/FONT]
[FONT=&quot]6-58 - (310-[/FONT][FONT=&quot]1[/FONT][FONT=&quot]5(c)[/FONT][FONT=&quot]. [/FONT][FONT=&quot]E[/FONT][FONT=&quot]xc[/FONT][FONT=&quot]eption-(New): Accept [/FONT]
[FONT=&quot]Secretary's Note[/FONT][FONT=&quot]: [/FONT][FONT=&quot]It was the action of the Correlating Committee that th[/FONT][FONT=&quot]i[/FONT][FONT=&quot]s proposal be reconsidered and [/FONT][FONT=&quot]c[/FONT][FONT=&quot]orr[/FONT][FONT=&quot]e[/FONT][FONT=&quot]lated with the action on Proposals 6-105 and 6[/FONT][FONT=&quot]-[/FONT][FONT=&quot]110. This action wil[/FONT][FONT=&quot]l [/FONT][FONT=&quot]be considered by the Panel as a Public Comment. [/FONT]
[FONT=&quot]SUBMITTER[/FONT] [FONT=&quot]: [/FONT][FONT=&quot]Frederic P[/FONT][FONT=&quot]. [/FONT][FONT=&quot]Ha[/FONT][FONT=&quot]r[/FONT][FONT=&quot]twell[/FONT][FONT=&quot], [/FONT][FONT=&quot]Amhe[/FONT][FONT=&quot]r[/FONT][FONT=&quot]s[/FONT][FONT=&quot]t[/FONT][FONT=&quot], MA [/FONT]
RECOMMENDATION [FONT=&quot]: Add an exception as follows: [/FONT]
[FONT=&quot]Exception[/FONT][FONT=&quot]: [/FONT][FONT=&quot]Where two different ampacities appl[/FONT][FONT=&quot]y to [/FONT][FONT=&quot]adjacent portions o[/FONT][FONT=&quot]f [/FONT][FONT=&quot]a circuit the higher ampaci[/FONT][FONT=&quot]ty [/FONT][FONT=&quot]shall be permitted to be used beyond the point of transition a distance equa[/FONT][FONT=&quot]l [/FONT][FONT=&quot]to 10 feet (3[/FONT][FONT=&quot].[/FONT][FONT=&quot]05 [/FONT]01) [FONT=&quot]or [/FONT][FONT=&quot]1[/FONT][FONT=&quot]0[/FONT][FONT=&quot]% [/FONT][FONT=&quot]of the c[/FONT][FONT=&quot]i[/FONT][FONT=&quot]rcuit length f[/FONT][FONT=&quot]i[/FONT][FONT=&quot]gured at the higher ampa[/FONT][FONT=&quot]city, [/FONT][FONT=&quot]wh[/FONT][FONT=&quot]i[/FONT][FONT=&quot]chever [/FONT][FONT=&quot]i[/FONT][FONT=&quot]s less. [/FONT]
[FONT=&quot]SUBSTANTIATION: This p[/FONT][FONT=&quot]r[/FONT][FONT=&quot]oposal will pe[/FONT][FONT=&quot]r[/FONT][FONT=&quot]mit more productive [/FONT][FONT=&quot]u[/FONT][FONT=&quot]se of the new ampacity tables by allo[/FONT][FONT=&quot]wing [/FONT][FONT=&quot]for short t[/FONT][FONT=&quot]r[/FONT][FONT=&quot]ansitional l[/FONT][FONT=&quot]e[/FONT][FONT=&quot]ngths without the necessit[/FONT][FONT=&quot]y [/FONT][FONT=&quot]o[/FONT][FONT=&quot]f [/FONT][FONT=&quot]splice[/FONT][FONT=&quot]s [/FONT][FONT=&quot]at [/FONT][FONT=&quot]t[/FONT][FONT=&quot]he point of transition. Although genera[/FONT][FONT=&quot]ll[/FONT][FONT=&quot]y [/FONT][FONT=&quot]applied to underground to raceway in a[/FONT][FONT=&quot]i[/FONT][FONT=&quot]r transi[/FONT][FONT=&quot]t[/FONT][FONT=&quot]ion[/FONT][FONT=&quot]s, [/FONT][FONT=&quot]the proposal also [/FONT][FONT=&quot]r[/FONT][FONT=&quot]ecognizes, for e[/FONT][FONT=&quot]x[/FONT][FONT=&quot]ample[/FONT][FONT=&quot], [/FONT][FONT=&quot]messenger [/FONT][FONT=&quot]c[/FONT][FONT=&quot]able to raceway transit[/FONT][FONT=&quot]i[/FONT][FONT=&quot]ons[/FONT][FONT=&quot]. [/FONT][FONT=&quot]The guiding princip[/FONT][FONT=&quot]le is [/FONT][FONT=&quot]that the pa[/FONT][FONT=&quot]r[/FONT][FONT=&quot]t of the cir[/FONT][FONT=&quot]c[/FONT][FONT=&quot]uit in an ambient that transfers heat mo[/FONT][FONT=&quot]r[/FONT][FONT=&quot]e [/FONT][FONT=&quot]r[/FONT][FONT=&quot]eadily (and thus permi[/FONT][FONT=&quot]t[/FONT][FONT=&quot]s a hig[/FONT][FONT=&quot]he[/FONT][FONT=&quot]r ampacity) can and will act as a heat sink for the adjacent part of the circuit[/FONT][FONT=&quot]. [/FONT][FONT=&quot]The submitter has bee[/FONT][FONT=&quot]n [/FONT][FONT=&quot]told that 15 feet has been widely used in industr[/FONT][FONT=&quot]y[/FONT][FONT=&quot]; [/FONT][FONT=&quot]the [/FONT][FONT=&quot]proposal errs on the conservat[/FONT][FONT=&quot]i[/FONT][FONT=&quot]ve side[/FONT][FONT=&quot]. [/FONT]
[FONT=&quot]PANEL ACTION[/FONT][FONT=&quot]: [/FONT][FONT=&quot]Accept. [/FONT]
[FONT=&quot]VOTE ON PANEL ACTION[/FONT][FONT=&quot]:[/FONT] [FONT=&quot]Unanimously Affi[/FONT][FONT=&quot]r[/FONT][FONT=&quot]mative[/FONT][FONT=&quot].


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[FONT=&quot]
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[don_resqcapt19]

[FONT=&quot]Log #746[/FONT]
[FONT=&quot]6- 105 - (Tables 310-16 through 310-31, Note 8(a), Exception No.4):Accept [/FONT]
[FONT=&quot]Secretary's Note: It was the action of the Correlating Committee that this proposal be reconsidered and correlated with the action on Proposals 6-58 and 6-110. This action will be considered by the Panel as a Public Comment. [/FONT]
[FONT=&quot]SUBMITTER: Nicholas R. Rafferty, Wilmington, DE [/FONT]
RECOMMENDATION [FONT=&quot]: Change wording from "having a length not exceeding 10 feet (3.05 m) and the number of conductors does not exceed 4." to "having a length not exceeding 10 feet (3.05 m) above grade and the number of conductors does not exceed 4." [/FONT]
[FONT=&quot]SUBSTANTIATION[/FONT] [FONT=&quot]: Article 300-5(d) requires the raceway to be at least 8 ft. above finished grade and at least 18" below grade. [/FONT]
[FONT=&quot]If the finished grade changes, or if the raceway is extended above the 8 ft. minimum to 10 ft. or if a manufactured 90 degree elbow is used below grade, this exception could not be used. [/FONT]
[FONT=&quot]PANEL ACTION[/FONT] [FONT=&quot]: Accept. [/FONT]
[FONT=&quot]VOTE ON PANEL ACTION:[/FONT] [FONT=&quot] Unanimously Affirmative. [/FONT]

 

[don_resqcapt19]

[FONT=&quot]Log#2253 6- 110 - (Tables 310-16 through 310-31, Note 8(c)-(New)): Accept in Principle [/FONT]
[FONT=&quot] Secretary's Note: It was the action of the Correlating Committee that this proposal be reconsidered and correlated with the action on Proposals 6-58 and 6-105. This action will be considered by the Panel as a Public Comment. [/FONT]
[FONT=&quot] The Correlating Committee agrees with Durham's comment. In addition the requirement is inappropriate in Note 8 because only derating for the number of conductors in a raceway is covered by the rule. SUBMITTER:[/FONT][FONT=&quot] J. [/FONT][FONT=&quot]W. Frasure, Houston, TX [/FONT]
[FONT=&quot] RECOMMENDATION: Add new Note 8(c) as follows: [/FONT]
[FONT=&quot] (c) Underground Raceway Exit Ampacities. Ampacity derating factors shall not be applied to underground conductors entering or leaving an underground direct burial trench or duct bank if such conductors have physical protection in the form of conduit, equipment cubicle, or other similar enclosure and the conductors do not have a length in excess of 10 feet. SUBSTANTIATION: In the application described above, the underground portion of the circuit acts as a heat sink and dissipates any small amount of extra heating that occurs in the aboveground portion of the circuit. Industrial applications have used 15 feet for these conditions for many years without problems. [/FONT]
[FONT=&quot] This note permits terminating underground circuits in switchgear, terminal boxes, metering enclosures, etc. without derating. [/FONT]
[FONT=&quot] PANEL ACTION: Accept in Principle. [/FONT]
[FONT=&quot] Revise the proposal as follows and identify it as a new Note 8(c): [/FONT]
[FONT=&quot] "8(c) Underground Exit Ampacities. Ambient temperature adjustment factors shall not be required for underground conductors entering or leaving an underground direct burial trench or duct bank if such conductors have a length of not more than 15 feet above grade. " [/FONT]
[FONT=&quot] PANEL COMMENT: The Panel believes the revised wording more accurately reflects the intent of the proposal, eliminates the restrictions of raceways or enclosures and correlates with changes Panel accepted in Proposal 6-105.[/FONT]
[FONT=&quot] VOTE ON PANEL ACTION: [/FONT]
[FONT=&quot] AFFIRMATIVE: 9[/FONT]
[FONT=&quot] NEGATIVE: Durham. [/FONT]
[FONT=&quot] EXPLANATION OF VOTE: [/FONT]
[FONT=&quot] DURHAM: Proposal-is inconsistent with action taken on Proposals 6-58 and 6-105. [/FONT]
[FONT=&quot] COMMENT ON VOTE: [/FONT]
[FONT=&quot] BROWN: I agree with Mr. Durham's negative vote comment. I am not changing my vote because I also agree with the panel's action on this proposal. I feel that we should correlate our actions on proposals 6-58 and 6-105 to agree with our action on this proposal. [/FONT]

 

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Thank you very much Don!