This article is intended to provide a preview of some of the more significant proposed changes to the 2005 NEC. This is a continuation of Part I provided in the July/August issue. It is important to understand that this summary is not intended to indicate that the Code is going to be revised as provided in this article, only that these are initial proposals that were acted on by the code-making panels in the proposal stage of the overall process. Part I reviewed various proposals from Articles 80 through 230. This collection of significant proposed changes provides a preview of proposed changes starting in Article 240 and visiting other revisions proposed to various other articles through to Chapter 8.
The second stage of the process includes opportunities for public review and comment to the proposed changes. It is important that the comments be submitted prior to the closing date of October 31, 2003, at 5:00 p.m. EST. The comment form is provided both in the printed copy of the Report on Proposals (ROP) and on the NFPA website atwww.nfpa.org. Each comment submitted will be acted on by the code-making panels in December in San Diego, California, and then included in the Report on Comments (ROC) when published.
The following provides a brief summary of the proposed changes and includes the proposal number, the section, and a short description of how each of these sections would be revised as a result of initial panel action to the proposals.
New Exception to Section 240.4(C)
A new exception was added to this requirement that will permit conductors to be protected by the next higher standard overcurrent device rating (above the ampacity of the conductors being protected) within the limitations of four specific conditions.
1. The next higher standard overcurrent device rating (above the ampacity of the conductors being protected) does not exceed 6 percent above the ampacity of the conductors being protected.
2. The ampacity of the conductors does not correspond with the standard ampere rating of a fuse or a circuit breaker without overload trip adjustments above its rating (but that shall be permitted to have other trip or rating adjustments).
3. The next higher standard rating selected does not exceed 1600 amperes.
4. The overcurrent device has been listed for use with the smaller conductors.
Devices rated 1600 amperes or less can be used to protect conductors rated smaller than the rating of the device if all four conditions are met. If any of the conditions are not met, than the current requirements in the general rule for devices rated over 800 amperes shall be followed.
Revision Section 240.4(E)
This section was revised by reorganizing the referenced sections within the existing rule into a list format that is consistent with the NEC Style Manual Section 3.3.2. This change does not have an impact on any of the current sections referred to by this section nor are there any added references. This list format is a logical conversion where the result is more practical for users of the Code.
Revision 240.20(B)(1), (2), and (3)
This revision to subdivisions (1), (2), and (3) replaces the word “approved” with the word “identified.” This change clarifies that handle ties used on circuit breakers as permitted in this section are required to be designed by the manufacturer and used within those limitations. This change will help prevent the use of nails, wire, or other unacceptable methods of connecting single-pole devices handles together to meet the requirements of this section.
This revision changes the word “conductors” to “each set of conductors feeding separate loads” in the first sentence of the rule. This change in wording provides clarification that multiple sets of conductors can be tapped to a single transformer secondary but each set must comply with all of the requirements in 240.21(C)(1) through (6).
Revision Section 240.24(B) Exception No. 2
This section was revised by adding the wording “in other than dwelling units” within the exception. This revision clarifies that guest rooms that meet the definition of “dwelling unit” are required to have the overcurrent protection devices for the occupancy readily accessible to the occupant. Other than dwelling units are only required to provide access to the overcurrent devices to authorized management personnel.
New Section 240.93 Series Ratings
This proposal as accepted introduces a new section under Part VIII Supervised Industrial Installations. This new provision allows the use of series rated systems when tested and selected under engineering supervision. Series rated combinations would now be allowable under supervised engineering where combinations of line-side overcurrent device and load-side circuit breaker are tested and marked on the end use equipment. The line-side device is to be selected under engineering supervision, and the load-side device must be tested and marked on the end use equipment by the manufacturer. The line-side device must be field-marked as well as the end use equipment.
Entire Code – Change in Terminology
This proposed change would replace the term “equipment grounding conductor” with the term “equipment bonding conductor” where appropriate throughout the sections in which it is used within Article 250, and it was also proposed to all of the code-making panels to address the term as used in any article under the responsibility of each panel. The proposed change in terminology is intended to work more effectively with the recent changes that clarify performance criteria and language in Article 250 that differentiates between the “grounding” and “bonding” and the performance aspects of each term. This proposed change is directed at increased understandability and usability of the Code requirements related to these two separate functions grounding and bonding.
Title of Article 250
This change incorporates the words “and bonding” into the title of Article 250. The title of the article would now be Article 250 Grounding and Bonding. There is no change to the wording of the scope of the article, which already includes the words “or bonding.”
Revision Section 250.28
This change draws a distinct differentiation and adds new terminology within this section to clearly identify the connection between the grounded conductor and the equipment grounding conductor of separately derived systems as a “system bonding jumper.” Previous editions of the Code have used the term “bonding jumper” as in 250.30(A) which, by definition, means something different than how it is used in this section. The revision provides clarity and increases understandability and application for users of the Code. The term “service-entrance conductors” from (D) has been removed and the words “supply conductors” have been added to clarify that the sizing requirements apply to the “supply conductors” whether they are service-entrance conductors or derived phase conductors of separately derived systems. A new definition has also been accepted to Article 100 that defines the new term “system bonding jumper” used in this section.
Revision and Reorganization of Section 250.30
This change reorganizes and restructures Section 250.30 for clarity and usability. It incorporates several technical changes also to clarify the rules. The sizing requirements for equipment bonding jumpers have been clarified to reference 250.102(C), which resolves sizing conflicts where the derived phase conductors are installed as parallel secondary conductors. The methods of connection for the grounding electrode conductor taps to the common grounding electrode conductor have been revised to be consistent with the methods permitted to the same concept allowed under the provisions of 250.64(D) for services. A clarification has been incorporated into Section 250.30(A)(7) to indicate that any of the electrodes in 250.52(A) shall be permitted to be used where structural metal building frame electrodes or where a metal water pipe grounding electrode is not available. The revisions to this section more clearly address grounding electrode conductor(s) requirements for individual separately derived systems and the common grounding electrode conductor concept for multiple separately derived systems as separate provisions.
Revise Section 250.32
The words “two or more” and “from a common service” have been removed from this section. The title of the section has been revised to include the words “feeder(s) or branch circuit(s)” to clarify applicability of the requirement. The revision clarifies that the grounding rules at separate buildings or structures are required to apply regardless of where the feeder(s) or branch circuit(s) supplying them originates. A new sentence has also been added to the Exception to read as follows: “For the purposes of this section, a multiwire branch circuit shall be considered a single branch circuit.”
New Section 250.147
This change adds a new Section 250.147 to include bonding requirements for switches in Article 250 that is consistent with those in Article 404 for switches. This added section is a logical placement for the requirements for grounding of switches as it directly follows the same requirements for bonding of grounding type receptacles. The added requirement is also consistent with the provisions currently contained in 404.9(B). Including the requirement in Article 250 improves usability and provides requirements within Article 250.
The term “furring strips” has been incorporated into this section, clarifying that even though they may not be framing members, that the 1-1/4″ clearance from any edge subject to nail or screw penetration must be maintained [see figure 1].
Revision Section 300.11(A)(1)
Section 300.11(A)(1) has been revised to address attaching additional wires for wiring method support to the grid of a fire-rated ceiling assembly. An added phrase, “and shall be permitted to be attached to the assembly,” now clarifies that additional wires installed for wiring method support in a fire-rated ceiling may be attached to the ceiling grid.
Section 300.22(B) (C) & (D)
The panel rejected a new concept that would divide air-handling spaces into:
1. Raised floor and ceiling cavity plenums
2. Ducts and plenums
“Plenum” cable would no longer be allowed inside ducts and plenums, and a new “duct cable” is being introduced in Articles 725, 760 and other “”low voltage”” articles under the purview of Panel 16. Panel 16 accepted the new concept, so the Technical Correlating Committee and the two panels will have to come to a consensus before or at the comments stage. This revision would remove the term “other spaces used for environmental air” from this section and other articles and provide wording consistent with that used in NFPA 90A-2002, The Standard for Installation of Air-Conditioning and Ventilating Systems. The Technical Correlating Committee has assigned a task group to work cooperatively with the panels and reach reasonable consensus to address the proposals in consistent fashion.
Revise Section 310.15(B)(2)(a)
The proposed revision to this section adds a more restrictive requirement to apply ampacity adjustment factors where more than two NM cables containing two or more current-carrying conductors each are bundled together and pass through wood framing members where fire-stopping or draft-stopping material is installed at the penetration. The ampacity adjustment factors specified in Table 310.15(B)(2)(a) would be required to be applied to the current-carrying conductors installed in this manner.
Revise Section 310.15(B)(2)(a)
A new sentence has been added to the existing rule that addresses adjustment factors where parallel conductors are installed. The new sentence clarifies that each current-carrying “wire” of a parallel set of conductors is required to be counted as current-carrying where application of correction factors is necessary.
New Section 310.15(B)(2)(c)
A new section was added to this section and reads as follows: “Installations Outdoors in Direct Sunlight. Where feeders or branch-circuits are installed in raceways outdoors on rooftops which are exposed to direct sunlight, the ampacities of Tables 310.16 and 310.18 shall be derated by a factor corresponding to an outdoor ambient temperature, plus 17 degrees C.”
New Section 312.21
This proposed change introduces a new section to Article 312 that requires repairing of plaster, drywall, etc., around cabinets and cut-out boxes as well as boxes and fittings similar to the requirements for boxes currently contained in Section 314.21.
Revision Section 314.20
Current provisions of the Code for supporting boxes allow screws to be used as a supporting means. This revision would identify the hazard of screws with coarse threads that pass through the interior of the box which may damage the insulation of the conductors. This revision clarifies that screws used to support boxes need to be installed so that the threaded portions are not exposed to the inside of the box or are protected from the conductors.
Proposals to CMP-7 and CMP-8 to remove the “uses permitted” section from each article as appropriate.
Apparent problems resulting from list formats in the cable wiring method articles and the raceway wiring method articles have resulted in the Technical Correlating Committee assigning a task group to review the issues and conflicts associated between “uses permitted” and “uses not permitted” within the articles and provide a recommendation to resolve these issues. The overall recommendation from the Usability Task Group to the panels by proposals is to remove the “uses permitted” section and revise the “”uses not permitted” section within each article as appropriate. The result of these revisions would leave only a “uses not permitted” section within each article and remove the task of having to be inclusive with a list of “uses permitted” for each article. The result basically would be any applications of these wiring methods not specifically limited by the “uses not permitted” section of wiring method article would be acceptable for use.
Revision Section 404.8 (B)
A new sentence has been added to this section stating, “A multipole general use snap switch shall not be permitted to be fed from more than a single circuit, unless listed and marked as a two-circuit or three-circuit switch. The voltage to the same single circuit snap switch shall not exceed 300 volts.”
The same hazard of circuits exceeding 300 volts fed to the same device exists as does voltages in excess of 300 volts for adjacent devices.
Revision Section 408.8(C)
This revision provides additional clarity and more specifically addresses locations where receptacles are not permitted at bathtub and shower locations. The change prohibits receptacles from being installed within a bathtub or shower stall as well as over those locations.
Revision Section 410.15(B)
This proposed change recognizes nonmetallic poles for the support of luminaires (lighting fixtures) such as parking lot luminaires. Nonmetallic poles, such as concrete poles, are becoming more common and this revision expands the requirement to beyond those poles of only the metallic types.
Revision Section 422.31(B)
This revision provides a sentence to this section that places additional restrictions on the provision for the lockable means for the switch or circuit breaker used as the disconnection means. The proposed change requires the lockable means to be permanently installed on or at the switch or circuit breaker which is also consistent with similar provisions for motor disconnecting means in 430.102(B) Exception.
Article 430 Change in Terminology
The term “full load amperes (FLA)” has been changed to the term “full load current (FLC)” to be consistent with the definition of ampacity in Article 100. It is more appropriate that the term current be used when describing loads, including motor loads.
New Part X to Article 430
A new Part X has been added to Article 430 and is titled “Adjustable Speed Drives.” The revision establishes a specific part of Article 430 to address key installation rules for motor adjustable speed drives. Existing provisions for adjustable speed drives currently contained in 430.2 and 430.22 Exception No. 2 were relocated under this new part and other installation requirements have been added as well.
Revise Section 430.102(B)
The last sentence of 430.102(B) has been deleted. The words “to be in sight from the motor and driven machinery location” in the first sentence of the exception have also been deleted. This revision clarifies that a disconnect would not be required at the motor if the conditions of either (a) or (b) of the exception have been met. This revision is not intended to eliminate the disconnect required within sight from the motor and driven machinery location generally, as currently required by the 2002 NEC.
New Article 506
This proposed new article would provide an alternative method of addressing electrical installations in atmospheres where fire and explosion hazards may exist due to flammable dusts, fibers, and flyings. This article would be an alternative to the requirements presently contained in Articles 500, 502, and 503 for electrical installations in these environments.
Revision Section 511.3
This section has been rearranged for a more logical order so that all requirements related to unclassified locations within commercial repair garages are located in 511.3(A) and all requirements related to the classified locations are located in 511.3(B). Previously some of the text in this section was located in exceptions and some was located in Article 514.
Revision Section 514.8
This proposed change eliminates the text that indicates the space within the earth, below a classified area is a Class I, Division I location. The definition of a Class I location in Article 500 states that an ignitible concentration of fuel and air must be present for a classified location to exist. Raceways installed under the classified location must continue to include a seal where the raceway emerges from below grade. The space in the earth below the classified location is unclassified where the space does not include enough oxygen to reach ignitible concentrations.
Revise Section 517.30(C)(3)
The proposed revisions to this section would now permit Types AC and MC cables for wiring methods for the emergency system where normally a nonflexible wiring method is required for mechanical protection. This alternative wiring method in cable form is now permitted to be installed in existing installations where it is impractical to install a nonflexible metal raceway.
New Definition in Section 547.2
The term “site-isolating device” is unique to Article 547 and is now defined as “a disconnecting means installed at the distribution point for the purposes of isolation, system maintenance, emergency disconnection, or connection of optional standby systems.” Section 547.9(A)(1) in the 2002 NEC described the purpose of this device and was, in fact, a definition of the term. This revision creates a definition and places it in 547.2 to conform to NEC Style Manual requirements.
Revision Section 547.9
This revision incorporates various technical changes and issues raised in proposals 19-14, 19-16, 19-17, 19-18, 19-19, 19-21, and 19-23. One key revision is the site-isolating device is required to be pole-mounted. Where the device is readily accessible at grade level it must meet all of the provisions for service equipment, including overcurrent protection and short-circuit current ratings.
The phrase “other than luminaires (fixtures)” has been added to 604.6(A)(3) and a new Section 604.3(F). The proposed change clarifies that the provisions of this section limiting length and size of the flexible cords utilized in manufactured wiring systems are not applicable to luminaires (fixtures). Subsection F permits cord-connected electric-discharge luminaires (fixtures) to be installed in accordance with the requirements of Section 410.30(C).
Changes to Article 600
This proposal combines revisions and new requirements into Article 600. A new definition of “section sign” would now be included in 600.2. A reference is made to signs installed in hazardous (classified) locations and a requirement to comply with the applicable provisions and requirements of Chapter 5. Additional language was accepted to provide clarification that secondary wiring is required to meet the requirements of Article 600, Part II. Another proposal has also been submitted to revise and expand the applicability of Part II of Article 600 from being limited to just field-installed skeleton tubing installations. See proposal 18-117 for more information.
The title of Section 680.26 has been revised from “680.26 Bonding” to “680.26 Equipotential Bonding.” The revision also inserts the word “equipotential” into 680.26(A); the proposed revisions to this section are intended to clarify the purpose of the bonding required by this section is to “eliminate voltage gradients in the pool area as prescribed” [see figure 2].
New Article 682
This proposal introduces a new Article 682 to the NEC. The title of the article would be “”Natural and Artificially Made Bodies of Water.”” The article would initially be comprised of three parts as follows:
Part I – General
Part II – Installation
Part III – Grounding and Bonding
This proposed new article is the result of the work of a CMP-17 task group to address the concerns for requirements that cover electrical installations associated with other bodies of water outside of the scope of Article 680.
New Definitions 770.2
Six proposed definitions of terms used in NFPA 90A have been added to this section.
New terms are: air duct, ceiling cavity plenum, raised floor plenum, duct distribution plenum, apparatus casing plenum, and air-handling plenum.
Revision Section 770.3
The proposed changes reflect a change in terminology used to describe “”other spaces used for environmental air”” to “”other air-handling spaces.”” The proposed revision recognizes Types OFNP and OFCP cables for use in plenums, including ceiling cavity plenums and raised floor plenums.
This proposal is consistent with several similar proposals (see list of Code Sections below) to revise the wording in each of the respective articles to a common format.
Panel 3 – 300.22, 725.3, 760.3, 770.3, 725.61, 725.71, 760.30, 760.31, 760.61, 760.71, 770.51, and 770.53 (Panel 3 rejected initially).
Panel 16 – 800.8, 820.3, 830.3, 800.51, 800.52, 800.53, 820.51, 820.51, 820.52, 820.53, 830.5, 830.54, 830.55, and 830.58 (Panel 16 accepted initially).
Panel 8 – 392.4 (Panel 8 accepted initially).
Panel 15 – 518.4 (Panel 15 accepted initially).
Panel 12 – 640.3 (Panel 19 accepted initially).
Panel 19 – 604.4 (Panel 19 accepted initially).
These proposals have the objective of clarifying the language used in the NEC and coordinating with the language used in NFPA 90A-2002, The Standard for Installation of Air-Conditioning and Ventilating Systems. These proposals would remove the term “other spaces used for environmental air-handling purposes” and replace it with the following terms as appropriate: ceiling cavity plenum, raised floor plenum, air-handling plenum, etc. There are six definitions of terms used to describe these spaces proposed in proposal 16-9.
Reorganization Articles 800, 820, and 830
These revisions reflect the work of a task group under guidance from the TCC to reorganize these articles in a more logical layout that is consistent and parallel between the articles and is in concert with the requirements of the NEC Style Manual.
The organization of the restructured article as proposed is shown below:
Part I – GeneralPart II – Wires and Cables Outside and Entering BuildingsPart III – ProtectionPart IV – Grounding MethodsPart V – Wires and Cables Within Buildings
Part VI – Listing Requirements.