Initial developments in the 2014 NEC for data/comm cables

The National Electrical Code (NEC) is published by the National Fire Protection Association (NFPA; www.nfpa.org) and is revised on a three-year schedule.

Sep 1st, 2012
Pennwell web 450 300

From the September, 2012 Issue of Cabling Installation & Maintenance Magazine

Code-making panels have taken initial actions, which can be reviewed and commented on until October 17.

By Stanley Kaufman, CableSafe Inc.

The National Electrical Code (NEC) is published by the National Fire Protection Association (NFPA; www.nfpa.org) and is revised on a three-year schedule. Development of the 2014 NEC officially began in the fall of 2011 with the submission of change proposals (public input) to NFPA by November 4, 2011.

The initial phase in the development of the 2014 NEC was completed when NFPA published the Report on Proposals (ROP), which showed the initial actions taken on all 3,745 proposals that had been submitted. The ROP can be downloaded from the NFPA website (http://bit.ly/OZnP7m). NFPA has also published a draft of the 2014 NEC, which incorporates all the changes accepted in the initial phase of Code development. The draft also can be downloaded from the NFPA site (http://bit.ly/N9kukL).

Interested parties can now review those initial actions and submit comments on the actions. The deadline for submission of public comments is October 17, 2012. The NEC Code-making panels will act on the comments when they meet in December 2012.

What are the proposed changes that are on track for inclusion in the 2014 NEC? We will review the changes of interest to manufacturers, installers and users of communications cable and connectivity products. These changes are in 11 different Articles in the Code and involve three Code-making panels.

As indicated in the tables, some of the changes involve topics or issues that are new, or at least have not been the subject of proposals in recent Code-revision cycles. The proposals dealing with field-assembled optical-fiber cables, plenum-rated cable ties, reorganization of the Article dealing with data center wiring and the introduction of a new Article on modular data centers are new issues/concepts for this Code-revision cycle.

Other changes involve multiple Code-revision cycles. The proposals dealing with riser installations, circuit integrity cables, raceways and cable routing assemblies are a continuation of issues/topics that were considered in the last Code-revision cycle and resulted in changes that are now in the 2011 NEC. Additional prohibitions on wiring in ducts with flammable materials are an extension of a fundamental requirement in the Code. The expansions may involve changes within an Article that already dealt positively with the issue/topic; for example, introducing plenum-grade cable routing assemblies in Article 800. Alternatively, the expansions may involve adopting a correlating change in other Articles; two examples are 1) introducing cable routing assemblies into Article 725 and 760, and 2) substituting communications raceways for optical-fiber raceways in Article 770 and signaling raceways in Article 725.

Articles dealing with new issues and topics

Field-assembled optical fiber cables. The current definition of an optical fiber cable in Article 770 is “A factory assembly of one or more optical fibers, having an overall covering, that transmits light for control, signaling and communications.” This definition does not recognize that some optical fiber cables are field-assembled by installing a tube and subsequently blowing fibers into the tube. Panel 16 actions on proposals 16-29 and 16-30 will revise the definition of an optical fiber cable to remove non-pertinent text and recognize field-assembled optical fiber cables.

Optical fiber Cable. A factory assembly or field assembly of one or more optical fibers, having an overall covering.

Informational Note: A field-assembled optical fiber cable is an assembly of one or more optical fibers within a jacket. The jacket, without optical fibers, is installed in a manner similar to conduit or raceway. Once the jacket is installed, the optical fibers are inserted into the jacket, completing the cable assembly.

A companion proposal (16-75) establishes listing requirements for field-assembled optical fiber cables. It provides for the listing of “a specific combination of jacket and optical fibers intended to be installed as a field-assembled optical fiber cable” that meet the requirement for general-purpose, riser or plenum optical fiber cable. In addition the jacket (tube) is required to meet the same requirements as a communications raceway.

For example, a specific combination of optical fibers and tubing listed as a plenum optical fiber cable would be tested twice; first, the tube would be tested to confirm that it passes the flame spread and smoke requirements for plenum communications raceway, and then the specific combination of tube and fibers would be tested to confirm that the combination passes the flame spread and smoke requirements for plenum optical fiber cable.

Plenum rated cable ties. The NFPA Standards Council has assigned primary responsibility for the fire protection of combustibles in air-handling spaces to the Technical Committee on Air Conditioning and its standard NFPA 90A, Standard for the Installation of Air-Conditioning and Ventilating Systems. NFPA 90A has requirements for discreet components in a plenum, including cable ties (see 4.3.11.2.6.5 and 4.3.11.5.5.6). In order to bring the NEC into correlation with NFPA 90A, proposals were submitted for Articles 300, 725, 760, 770, 800 820 and 830 to establish requirements for listing plenum rated cable ties and to require that cable ties used in plenums (other space used for environmental air) be plenum grade.

See actions on proposals 3-86, 16-42, 16-100, 16-135, 16-166 and 16-225. Panels 3 and 16 accepted the concept of plenum grade cable ties but accepted different terminology. Consequently, the Correlating Committee directed that a joint task group consisting of members of Panel 3 and Panel 16 be formed to provide recommendations to reconcile the differences. The task group’s recommendations will be in the form of public comments that the panels will act on.

Data center wiring. Article 645, Information Technology Equipment, covers information technology equipment (computers), power wiring and signal wiring in an information technology equipment room (computer room). If you’re primarily interested in data/comm (signaling) wiring you may find the present requirements difficult to follow because the signal wiring requirements are not separated from the power wiring requirements. Panel 12 action on proposal 12-109 reorganizes the entire Article into three parts, Part I – General, Part II – Power Circuits, and Part III – Signaling Circuits. The reorganization greatly improves the usability of the Article. (Full disclosure: I submitted the proposal.) The chairman of Panel 12 appointed a task group to review the organization and the Correlating Committee directed that the reorganized Article be reviewed for compliance with the NEC Style Manual; it also directed that other editorial changes be made.

Panel 12 and the Correlating Committee accepted a new Article (646) (proposal 12-147) covering modular data centers. The chairman of Panel 12 appointed a task group to review the new Article and the Correlating Committee directed that the new Article be reviewed for compliance with the NEC Style Manual.

Proposals dealing with continuing issues and topics

Riser installations. Panel 3 actions on proposals 3-159, 3-160, 3-192, 3-193, 3-205 and 3-206 require riser or plenum rated class 2, class 3 and power-limited fiber alarm cables for installations rising from floor to floor, i.e. penetrating one or more floors (other than in one- and two-family dwellings). The 2011 NEC permits general-purpose rated class 2, class 3 and power-limited fire alarm cables for installations penetrating only one floor. Similar requirements for the use of riser and plenum optical fiber, communications and CATV cables are in the 2011 NEC.

The Correlating Committee directed that a joint task group consisting of members of Panel 3 and Panel 16 be formed to provide recommendations to reconcile similar, but not identical text used by Panels 3 and 16 to describe cables penetrating one or more floors. The task group’s recommendations will be in the form of public comments that the panels will act on.

Prohibitions on cables in ducts carrying flammable materials. Section 300.22(A) prohibits the installation of any wiring system in ducts used to transport dust, loose stock or flammable vapors. This requirement only applies to Chapter 8 (Communications) where it is specifically referenced in Chapter 8; see 90.3 Code Arrangement. The 2011 NEC added a reference to 300.22(A) in 800.3 “Other Articles” and Panel 16 added similar requirements in Articles 770, 820, 830 and 840 in its actions on proposals 16-36, 16-161, 16-219 and 16-269.

Signaling, optical fiber and communications raceways. The 2008 edition of the NEC contained listing requirements and applications for signaling raceways (Article 725), optical fiber raceways (Article 770), communications raceways (Article 800) and CATV raceways (Article 820). Each of these families of raceways had general-purpose, riser and plenum grades. The 2011 NEC began the process of consolidating these redundant raceway types by eliminating CATV raceways and replacing them with communications raceways. The 2011 NEC also permitted communications raceways to substitute for optical fiber raceways so that an installer only had to carry two types, signaling and communications raceways.

Panel 16 action on proposal 16-81 continued the consolidation process by eliminating optical fiber raceways and substituting communications raceways.

Panel 3 action on proposal 3-156 deletes the applications for signaling raceways and substitutes communications raceways. Panel 3 action on proposal 3-163a changes the listing requirements for signaling raceways to listing requirements for communications raceways; consequently the listing requirements for communications raceways are covered twice, in 725.179 and in 800.182. Panel 16 action on proposal 16-140 changes the text of the requirements for listing communications raceways, but the change is editorial and will not result in a change in test requirements.

Panel 3 action on proposal 3-202 permits power-limited fire alarm cables to be installed in communications raceways. (Note: Fire alarm raceways do not exist so there is no proposals to permit communications raceways to substitute for fire alarm raceways.)

If all of these changes are adopted by the 2014 NEC, communications raceways (general-purpose, riser and plenum grades) will be permitted for use with signaling cables (Article 725), power-limited fire alarm cables (Article 760), communications cables (Article 800), CATV cables (Article 820) and network-powered broadband communications cables (Article 830). Signaling and optical fiber raceways will be eliminated.

Cable routing assemblies. Cable routing assemblies are widely used in data centers as a support/management systems for cables. They were designed for use with optical fiber cables, but they are also used for data (class 2) and communications cables. The fire tests for listing general-purpose, riser and plenum cable routing assemblies are identical to the fire tests for listing general-purpose, riser and plenum raceways. UL 2024 Standard for Signaling, Optical Fiber and Communication Cable Raceways and Cable Routing Assemblies, covers the listing of cable routing assemblies as well as signaling, optical fiber and communications raceways. Applications of general-purpose and riser cable routing assemblies were introduced for use with optical fiber and communications cables in Articles 770, 800, 820 and 830 in the 2011 NEC.

The 2011 NEC does not include applications of cable routing assemblies with data (class 2) circuit cables, even in a computer room that complies with Article 645. Note that a communications cable that is being used in place of a class 2 cable is required to be installed in accordance with Article 725, not Article 800. Consequently, communications cables used for communications circuits are permitted to be run in cable routing assemblies but communications cables carrying class 2 circuits are not permitted to be run in cable routing assemblies. This is clearly an inconsistent and confusing situation that will be corrected if the direction of the initial actions of Panel 3 on a series of proposals involving cable routing assemblies are continued through the comment stage. See proposals 3-118 and 3-171.

Definition. A cable routing assembly is defined in section 770.2 of the 2011 NEC. Panel 16 action on proposal 16-23 added the definition to Section 800.2 because it “promoted usability.” Panel 3 action on proposal 3-118 adopted a different definition of cable routing assembly in section 725.2. The NEC Correlating Committee directed that there be only one definition of a cable routing assembly and that it be placed in one Article in Chapter 8. The Correlating Committee, in the minutes of its April 2012 meeting, stated, “The Correlating Committee suggests that 800.2 may be the most appropriate location for the definition.”

The Correlating Committee directed that a joint task group consisting of members of Panel 3 and Panel 16 be formed to resolve issues concerning the definition of a cable routing assembly. The task group’s recommendations will be in the form of public comments that the panels will act on.

Listing. Panel 16 action on proposal 16-81 deleted Section 770.182, the section in the 2011 NEC that covers the listing of cable routing assemblies and optical fiber raceways. This was done because optical fiber raceways were replaced by communications raceways and the listing of cable routing assemblies was redundantly covered by Sections 770.182 and 800.182. Panel 16 action on proposal 16-140 added listing of plenum cable routing assemblies to Section 800.182 and made reference to the revised UL 2024, which now covers raceways and cable routing assemblies.

Panel 3 action on proposal 3-118 established redundant listing requirements for cable routing assemblies and communications raceways in section 725.179. This is an issue for the Panel 3 and 16 task group to address.

Installation and applications. Panel 16 actions on proposals 16-62, 16-63, 16-71, 16-119, 16-120, 16-131, 16-194, 16-195, 16-204, 16-245, 16-247, 16-248 and 16-255 established applications and installation requirements for plenum cable routing assemblies but limited their applications to general-purpose and riser applications only. Plenum applications were not permitted because the current edition (2012) of NFPA 90A Standard for the Installation of Air-Conditioning and Ventilating Systems, does not recognize cable routing assemblies, and NFPA 90A is the primary NFPA standard for combustibles in plenums.

Panel 3 actions on proposals 3-118 and 3-171 established applications for general-purpose, riser and plenum cable routing assemblies, including limiting plenum cable routing assemblies to general-purpose and riser applications only.

Panel 16 actions on proposals 16-57, 16-116, 16-191 and 16-245 established support requirements for cable routing assemblies. Lack of support requirements was an issue in the consideration of the cable routing assembly proposals in the last Code cycle.

Sections 770.133, 800.133, 802.133 permit the installation of optical fiber, communications, CATV and low-power network-powered communications cables in the same cable tray, enclosure, raceway or cable routing assembly.

Installation of optical fiber, communications CATV and low-power network-powered communications cables along with class 2, class 3 and power-limited fire alarm cables is permitted in the same cable tray, enclosure or raceway, but not in a cable routing assembly. In order to correlate with the acceptance of cable routing assemblies in Article 725 and 760, Panel 16 actions on proposals 16-68, 16-125, 16-200, 16-251 and 16-252 permit installation of optical fiber cables, communications, CATV and low-power network-powered communications cables along with class 2, class 3 and power-limited fire alarm cables in the same cable routing assembly. Panel 3 actions on proposals 3-118 and 3-171 permit class 2, class 3 and power-limited fire alarm cables to be installed along with optical fiber cables, communications cables, CATV cables and low-power network-powered communications cables in the same cable routing assembly.

Circuit integrity cables

Circuit integrity data/comm cables are recognized in the 2011 NEC. Article 725 defines a circuit integrity (CI) cable as “Cable(s) used for remote-control, signaling, or power-limited systems that supply critical circuits to ensure survivability for continued circuit operation for a specified time under fire conditions.” There are similar definitions in Article 760 for a fire alarm circuit integrity (CI) cable and in Article 800 for communications circuit integrity (CI) cable.

There are two types of circuit integrity cables—those that are not intended to be installed in raceway (or conduit) and those that use raceway as part of the design for achieving survivability. Circuit integrity cables that use raceway for achieving survivability are considered to be part of a “listed electrical circuit protective system.”

Panel 3 actions on proposals 3-165, 3-208 and 3-210 added requirements for the listing of an electrical circuit protective system for Articles 725 and 760 and clarified that only those CI cables that are part of an electrical circuit protective system are permitted to be installed in a raceway. Panel 16 actions on proposals 16-26a and 16-85a adopted similar requirements for the listing of optical fiber circuit integrity cables (Article 770) and communications circuit integrity cables (Article 800).

Panel 3 action on proposal 3-178 establishes support requirements for fire alarm circuit integrity cables located within 7 feet of the floor.

Panel 3 and the Correlating Committee actions on proposal 3-170 creates a new Article to cover the installation of CI cables; Article 728 Fire Resistive Cable Systems. Article 728 defines a fire resistive cable system as, “A cable and components used to ensure survivability of critical circuits for a specified time under fire conditions.” Using the term “fire resistive cables” in the scope of the new article may cause some confusion with plenum cables that are listed “as having fire-resistant and low-smoke producing characteristics.”

Panel 16 actions on proposals 16-26a and 16-85a added a definition of an electrical circuit protective system to Articles 770 and 800. It defines an electrical circuit protective system as, “A system consisting of components and materials intended for installation as protection for specific electrical wiring systems, with respect to the disruption of electrical circuit integrity upon exterior fire exposure.” In my opinion, this definition needs to have a clarifying information note in Article 770 to explain the reason why a definition dealing with electrical circuit integrity is in an article covering optical fiber cables.

The Correlating Committee directed that a joint task group be formed to provide recommendations to reconcile similar, but not identical text accepted by Panels 3 and 16 in their actions on the circuit integrity proposals. The task group’s recommendations will be in the form of public comments that the panels will act on.

Next step in development

The publication of the Report on Proposals kicks off the next step of the Code development process—the comment stage. Comment forms are available on the NFAP website. (http://bit.ly/RtHI7G)

The content of comments run the gamut from negative (reject the proposal) to conditionally supportive (accept the proposal in principle by making the following improvements or corrections) to completely supportive (keep up the good work). Considering that it takes some effort to submit a comment, it shouldn’t be surprising that most comments seek a change in the action on a proposal. I encourage participation in the Code development process by submission of comments, including supportive comments. ::

Stanley Kaufman, Ph.D. is principal of CableSafe Inc. and a consultant to the Communications Cable and Connectivity Association (CCCA; www.cccassoc.org). This paper, provided by the CCCA, is offered for general information and educational purposes. It is not offered, intended, nor should it be relied upon as legal advice. The paper does not set forth the views of any member or any other party, nor may it be taken as such. CCCA makes no warranty regarding the accuracy of the information provided in this paper, and expressly disclaims any implied warranties and any liability for use of the paper or reliance on views expressed in it. CCCA does not endorse, approve or certify any information set forth in this paper, nor does it guarantee the accuracy, completeness, efficacy, timeliness or correct sequencing of such information. Use of this paper and the views expressed in it is voluntary, and reliance on it should only be undertaken after independent review of its accuracy, completeness, efficacy, and timeliness, and based on the individual facts and circumstances of a user.

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