2011 National Electrical Code

2011 National Electrical Code

®

Changes of Interest to Data/Comm Cabling Contractors,

Users and Code Enforcement Officials

The National Electrical Code is published by the National Fire Protection Association with revisions on a three-year schedule. The 2011 NEC

®

, which replaces the 2008 NEC, was released by NFPA in August 2011. There were many changes of interest to manufacturers, installers and users of communications cable and connectivity products. The purpose of this document is to educate and communicate those relevant changes in the NEC.

The place to start reading the National Electrical Code is in the beginning, in Article 90-Introduction. Although there are no significant changes to Article 90 in the 2011 NEC, we start with this article

because it contains special arrangements for communications installations.

NFPA 70, NFPA, National Fire Protection Association, National Electrical Code, and NEC are registered trademarks of the National Fire Protection Association.

Article 90

Introduction

Section 90.2 Scope states that the NEC “covers the installation of electrical conductors, equipment, and raceways; signaling and communications conductors, equipment, and raceways; and optical fiber cables and raceways” in “Public and private premises, including buildings, structures, mobile homes, recreational vehicles, and floating buildings.” It also states the “Code does not cover” “Installations of communications equipment under the exclusive control of communications utilities located outdoors or in building spaces used exclusively for such installations”.

Section 90.3 Code Arrangement states that “Chapters 1, 2, 3, and 4 apply generally” and that “Chapter 8 covers communications systems and is not subject to the

requirements of Chapters 1 through 7 except where the requirements are specifically referenced in Chapter 8.” Section 90.2 also states that “Chapters 5, 6, and

7 apply to special occupancies, special equipment, or other special conditions. These latter chapters supplement or modify the general rules.”

What is the significance of these requirements? The NEC covers communications

equipment, wires and cables installed in most buildings; it includes optical fiber cables and raceways too. However, it exempts telephone company central offices because it has an exemption for communications utility installations under the exclusive control of the utility. It does not exempt telephone switching offices run by a nonutility such as a large university or a nonutility provider of telephone service.

Also, the communications chapter (Chapter 8) of the NEC is independent of the rest of the code; only those electrical wiring requirements in Chapters 1 through 7 that are referenced in Chapter 8 apply to Chapter 8. One example is that the cable tray fill requirements in Article 392 (Cable Trays) do not apply to installations of

communications cables covered by Chapter 8. They do apply to installations of data cables (class 2 cables) because these are in Article 725. They don’t apply to optical fiber cables because the cable tray fill requirements are written apply to electrical cables only.

Data wiring (class 2 wiring) is covered by Article 725 and some computer room

installations are covered by Article 645. These Articles are permitted to (and do) modify the general wiring rules in Chapters 1 through 4; however they are not permitted to modify the wiring rules for communications installations without a reference from Chapter 8; this is significant for installations of communications equipment in a computer room where Article 645 is applied to the IT equipment but not the communications equipment.

ARTICLE 300

Wiring Methods

Wiring in Air Ducts and Plenums

New Section 300.22(C)(2) was added to cover wiring supported by cable trays in other spaces used for

environmental air. Section 300.22(C)(2)(a) permits metal cable tray systems to support the various wiring methods that are permitted to be installed in other spaces used for environmental air. Section 300.22(C)(2)(b) permits wiring methods that are not already permitted to be installed in other spaces used for environmental air to be installed in solid side and bottom cable tray systems with solid metal covers.

Section 300.22(C) has been revised to clarify that “Other Spaces Used for Environmental Air

(Plenum)” applies “to spaces not specifically fabricated for environmental air-handling purposes but used for air-handling purposes as a plenum.” The section also has a new Informational Note that states that the phrase “Other Spaces Used for Environmental Air (Plenum)” correlates with the term “plenum” in NFPA 90A- 2009, Standard for the Installation of Air-Conditioning and Ventilating Systems “where the plenum is used for return air purposes, as well as some other air-handling spaces.”

Section 300.22(C)(2) in the 2008 NEC has requirements for equipment installed in other spaces used for environmental air. An Informational Note was added in the 2011 NEC in section 300.22(C)(3) to provide guidance on how to test that equipment. Reference is made to ANSI/UL 2043-2008, Fire Test for Heat and Visible Smoke Release for

Discrete Products and Their Accessories Installed in Air-Handling Spaces.

What is the significance of these changes? Section 300.22(C)(1) in the 2008 NEC,

which lists all the permissible wiring methods for other spaces used for environmental air, includes only one type of cable tray system, “solid bottom metal cable tray with solid metal covers.” It doesn’t permit open cable trays even if the cable tray supports wiring methods such as Type CMP cable that is permitted in a return air plenum unsupported by a cable tray. That oversight has been fixed in the 2011 NEC which permits plenum cables to be supported by open metal cable trays in a typical ceiling or underfloor plenum installation.

The informational note referring to NFPA 90A is significant because the NFPA Standards Council has assigned primary responsibility for fire protection of

combustibles in air handling spaces to the Technical Committee on Air-Conditioning and it’s document NFPA 90A, Standard for the Installation of Air-Conditioning and

Ventilating Systems. Correlating NFPA 70 (the NEC) and NFPA 90A is complicated by the difference in terminology used in the two documents. See the table below for a guide to reconciling the terminology used in the two documents.

NFPA 90A Terminology NEC Terminology

Air Duct Duct Specifically Fabricated for Environmental Air

(300.22(B))

Plenum Plenum

Ceiling Cavity Plenum Other Spaces Used for Environmental Air (Plenum)

Raised Floor Plenum Other Spaces Used for Environmental Air (Plenum)

Air-Handling Unit Room Plenum Other Spaces Used for Environmental Air (Plenum)

Apparatus Casing Plenum Plenum Specifically Fabricated to Transport

Environmental Air (300.22(B) in the 2008 NEC) Section 4.3.4 of NFPA 90A-2009 states that “Wiring shall not be installed in air ducts” unless it is “directly associated with the air distribution system and does not exceed 1.22m (4 ft).” The listing requirements for the four-foot lengths of plenum cable that are permitted are the listing requirements currently used by UL and other testing

laboratories to list plenum cable. Annex note A.4.3.4.4 explains that “Electrical wires and cables and optical fiber cables installed in metal raceways or metal sheathed cable are not considered to be exposed to the airflow, and need not meet the requirements of 4.3.4.4.” NEC section 300.22(C) correlates with section 4.3.4 of NFPA 90A-2009 in its requirements for wiring in air ducts.

Section 4.3.11.3.3 of NFPA 90A-2009 states that “Electrical wires and cables or optical fiber cables, or optical fiber and communications raceways” in apparatus casing

plenums “shall comply with 4.3.4.” When the title of section 300.22(B) was changed from “Ducts or Plenums Used for Environmental Air” in the 2008 NEC to “Ducts Specifically Fabricated for Environmental Air” in the 2011 NEC, the NEC lost any requirements for wiring in apparatus casing plenums.

NFPA 90A-2009 defines an apparatus casing plenum as “A sheet metal construction attached directly to a fan enclosure, fan coil unit, air handling unit, or furnace bonnet for the purpose of connecting distribution ducts.” The loss of coverage for wiring in

apparatus casing plenums is not significant because it is unlikely that there would ever be any reason to install wiring in one.

Section 300.22(D) in the 2008 and the 2011 NEC defers to Article 645 for “Electrical wiring in air-handling areas beneath raised floors for information technology equipment” and thereby correlates with section 4.3.11.5.5.5 of NFPA 90A-2009 that exempts

“electrical wires, listed plenum communication and fiber raceways, and optical-fiber cables in computer/data processing rooms” from the wiring rules for cables in raised floor plenums provided the computer rooms “are designed and installed in accordance with NFPA 75, Standard for the Protection of Information Technology Equipment.”

Article 645

Information Technology Equipment

Conditions for the Use of Article 645

Section 645.4 of Article 645 in the 2008 NEC states “This article shall apply, provided all of the following conditions are met:” It then lists five conditions. Section 645.4 of Article 645 in the 2011 NEC states “This article shall be permitted to provide alternate wiring methods to the provisions of Chapters 1 through 4 for power wiring, 725.154 for

signaling wiring, and 770.113(C) and Table 770.154(a) for optical fiber cabling when all of the following conditions are met:” It then lists six conditions.

What is the significance of this change? Article 645 is based on an engineering

trade-off. In return for providing additional fire protection (that’s the 5 or 6 conditions) relief from the plenum wiring rules for power wiring and signaling cabling is permitted. At least that is generally recognized as the intent, however the 2008 NEC required (shall apply) that the article be used if the 5 conditions were met. The 2011 NEC has been reworded to clarify that the use of the article is voluntary (shall be permitted) and furthermore clearly states that the alternative wiring methods are for power wiring (Chapters 1 through 4) and data wiring and optical fiber cabling only. No mention is made of communications wiring because Article 645 is not permitted to modify the requirements for communications wiring without a reference from Article 800 (Communications), and there is no reference to Article 645 in Article 800.

Article 645 permits the use of non-plenum-rated power cords and non-plenum-rated data cables in the underfloor plenum but it does not permit the use on non-plenum-rated communications cables if the cables are connected to communications equipment. Definitions

Section 645.2 has five new definitions: 1. Critical Operations Data System

2. Information Technology Equipment (ITE) 3. Information Technology Equipment Room 4. Remote Disconnect Control

What is the significance of these new definitions? Clearly an

article covering “Information Technology Equipment” is incomplete without a definition of what the article is all about. The difficulty in defining IT equipment is that it’s very similar to the definition of communications equipment. A definition of Communications Equipment is in Article 100 and it is not new to this edition of the Code. The definition of IT Equipment states what it is (creates and manipulates data, voice and video) and that it is not

communications equipment processing communications circuits. Communications circuits are defined in 800.2. Basically the definition of IT Equipment defers to the definition of

Communications Equipment; any equipment that appears to be both IT Equipment and Communications Equipment is

Communications Equipment. Since it is Communications Equipment, the installation requirements are in Article 800, not Article 645. The

definition of IT Equipment correlates with sections 725.139(D)(1) and 800.133(A)(1)(c) which state that when a class 2 or 3 circuit and a communications circuit are in the same cable, the class 2 or 3 circuit is reclassified as a communications circuit. Data circuits are class 2 or 3 circuits; see 725.121(A)(4).

It is equally clear that an article that covers information technology equipment in an information technology equipment room needs to have a definition of an IT Equipment Room. The new definition is extracted from NFPA 75 -2009, Standard for the Protection of Information Technology Equipment.

Likewise, a definition of zone is required because large computer rooms are divided into zones for fire protection. The definition of zone is new in the 2011 edition of the Code. Critical Operations Data Systems and Remote Disconnect Control are defined because these new concepts are the basis for a major technical change in Article 645. (Continue on to read about that change.)

Other Articles

Section 645.3 Other Articles was added to the 2011 NEC. It covers: (A) Spread of Fire or Products of Combustion.

(B) Plenums. (C) Grounding.

(D) Electrical Classification of Data Circuits. (E) Fire Alarm Equipment.

(F) Communications Equipment.

What is the significance of this new section? It has become

common practice for electrical inspectors to classify any room with a raised floor and computers in it to be a computer room that must comply with Article 645. The new “Other Articles” section clarifies which other parts of the Code apply.

Section (A) refers to the firestopping sections of the code.

Section (B) refers to all the sections that cover wiring in an “other space used for environmental air” above an IT room, i.e., a ceiling cavity plenum. There is no relief from the plenum wiring requirements for other spaces used for environmental air above an IT room, only in the space beneath it in the raised floor plenum.

Section (C) refers to the grounding requirements for conductive optical fiber cables such as armored optical fiber cables.

Section (D) leads the user to the reclassification of class 2 and 3 circuits as

communications circuits when they are in the same cable with communications circuits. Section (E) defers to Article 760 for the installation of fire alarm systems in an IT room. Section (F) defers to Article 800 for the installation of communications equipment in an IT room, but asserts that the powering of communications equipment in an IT room is covered by Article 645. There is no conflict with Article 800 if Article 645 covers the power wiring for communications equipment because Article 800 has no provision for powering of communications equipment.

Section (G) is similar to section (F) but it applies CATV systems.

Abandoned Cables

Section 645(F) of the 2008 NEC requires that abandoned cables be removed unless they are contained in metal raceway. The 2011 NEC deleted the word “metal”.

What is the significance of this change? Cables in raceways both

metallic and nonmetallic will not be required to be removed thereby treating metallic and nonmetallic raceways the same.

Disconnection Means (Emergency Power Off)

Section 645.10 of the 2008 NEC requires that there be disconnecting means for each zone in the IT room. Section 645.10 of the 2011 NEC has two alternatives for the disconnecting means, (A) covers remote disconnect controls with requirements the same as the 2008 NEC and (B) covers critical operations data systems. Critical operations data systems (defined in 645.2) are permitted to have alternate disconnecting means provided that five additional

conditions are met:

(1) An approved shut down procedure has been established

(2) Qualified personnel are continuously available 24/7 (3) Smoke sensors are in place. (4) A fire suppression system is in place.

(5) Plenum cables are used for signaling

What is the significance of this change? Compliance with Section 645.10 of the 2008

NEC is typically achieved by placing an emergency power off (EPO) switch at each door. There are documented cases of unscheduled shut downs of computer rooms by the accidental or improper engagement of the EPO. In order to deal with this issue, section 645.10 of the 2011 NEC has two alternatives for the disconnecting means, the traditional EPO at the door or an alternative process for critical IT rooms. Just as the provisions of Article 645 involve an engineering trade-off of additional fire protection in exchange for relief from the plenum wiring rules, the critical operations data system involves an additional engineering trade-off of providing more fire protection in

exchange for relief from having an EPO by the door. Part of that additional trade-off is to undo part of the existing engineering trade-off is that the raison d’être for the article, viz., relief from the plenum wiring rules. Critical operations data systems still have a

dispensation from the plenum wiring rules for power cables but plenum grade signaling cables are required.

ARTICLE 770

Optical Fiber Cables and Raceways

ARTICLE 800

Communications Circuits

ARTICLE 820

Community Antenna Television and Radio Distribution

Systems

&

ARTICLE 830

Network-Powered Broadband Communications

Systems

The changes to these articles are presented together because of the high degree of parallelism between these articles.

Optical Fiber, Communications and CATV Raceways

Section 820.182 of the 2008 NEC which contained the listing requirements for Plenum, Riser and General-Purpose CATV Raceways was deleted and does not appear in the 2011 NEC. Likewise all applications and installation rules for CATV raceway were deleted. Communications raceways are now permitted to be used in all

applications that previously used CATV raceways. Another new use for communications raceways is as a permitted substitute for optical fiber raceways.

Optical fiber and communications raceways have now been defined in Articles 770 and 800 and their permitted applications were changed to prohibit them from installation in air ducts.

The applications of optical fiber raceways and communications raceways are shown in the tables below. See Table 770.154(a) in the 2011 NEC for a complete table showing the Applications of Listed Optical Fiber Cables and Raceways, and Cable Routing Assemblies in Buildings. See Table 800.154(a) for the comparable table for

Applications of Optical Fiber Raceways

Applications

Raceway Type

Plenum Optical Fiber Raceway Riser Optical Fiber Raceway General-Purpose Optical Fiber Raceway In Air Ducts In air ducts N N N

In metal raceway that complies with 300.22(B) Y Y Y

In Other Spaces Used for Environmental Air (Ceiling Cavity, Raised Floor and Air-Handling Room Plenums)

In other spaces used for environmental air Y N N

In metal raceway that complies with 300.22(C) Y Y Y

Supported by open metal cable trays Y N N

Supported by solid bottom metal cable trays with

solid metal covers Y Y Y

In Risers

In vertical runs Y Y N

In metal raceways Y Y Y

In fireproof shafts Y Y Y

In riser cable routing assemblies N N N

In one- and two-family dwellings Y Y Y

Within Buildings in other than Air-Handling Spaces and Risers

General Y Y Y

Supported by cable trays Y Y Y

In distributing frames and cross connect arrays Y Y Y

Applications of Communications Raceways

Applications

Raceway Type

Plenum Communications Raceways Riser Communications Raceways General-Purpose Communications Raceways In Air Ducts In air ducts N N N

In metal raceway that complies with

300.22(B) Y Y Y

In Other Spaces Used for Environmental Air (Ceiling Cavity, Raised Floor and Air-Handling Room Plenums)

In other spaces used for environmental

air Y N N

In metal raceway that complies with

300.22(C) Y Y Y

Supported by open metal cable trays N N N

Supported by solid bottom metal cable

trays with solid metal covers Y Y Y

In Risers

In vertical runs Y Y N

In metal raceways Y Y Y

In fireproof shafts Y Y Y

In riser cable routing assemblies N N N

In one- and two-family dwellings Y Y Y

Within Buildings in Other Than Air-Handling Spaces and Risers

General Y Y Y

In one- and two-family dwellings Y Y Y

In multifamily dwellings Y Y Y

In nonconcealed spaces Y Y Y

Supported by cable trays Y Y Y

Under carpet N N N

In distributing frames and cross-connect

arrays Y Y Y

What is the significance of these changes? Signaling (Article 725), Optical Fiber

(Article 770), Communications (Article 800) and CATV Raceways (Article 820) are all available in plenum, riser and general-purpose grades. A great deal of redundancy exists because, for example, the only difference between Signaling, Optical Fiber, Communications and CATV plenum raceways is the label. The same is true for the riser and general-purpose versions. Panel 16 started the process of reducing redundancy by eliminating the CATV raceways and permitting communications raceways to be used instead. Further reduction in redundancy in future editions of the NEC is facilitated by permitting communications raceways to substitute for optical fiber raceways.

Optical fiber and communications raceways were prohibited from installation in air ducts in order to correlate with section 4.3.4.1 of NFPA 90A-2009.

Introduction of Cable Routing Assemblies

Cable routing assemblies are defined in section 770.2 and listing

requirements for general-purpose and riser grades are in sections 770.182 and 800.182. Applications and installation rules are in sections

770.154 and 770.113. These sections were completely rewritten (more about that below) and the cable routing assemblies were included in the revisions. The applications of cable routing assemblies are shown in the table below. See Table 770.154(a) in the 2011 NEC for a complete table showing the Applications of Listed Optical Fiber Cables and Raceways, and Cable Routing Assemblies in Buildings. The introduction of cable routing assemblies was also accommodated in sections 770.133, 800.133, 820.133 and 830.133 which cover which cables are permitted together in the same raceway, cable tray enclosure and now cable routing assemblies. The cables from Articles 770, 800, 820 and the low power cables from Article 830 are permitted together in cable routing assemblies.

Applications of Cable Routing Assemblies

Applications

Cable Routing

Assembly Type

Riser Cable Routing Assemblies General-Purpose Cable Routing Assemblies In Air Ducts In air ducts N N

In metal raceway that complies with 300.22(B) N N

In Other Spaces Used for Environmental Air (Ceiling Cavity, Raised Floor and Air-Handling Room Plenums)

In other spaces used for environmental air N N

In metal raceway that complies with 300.22(C) N N

In plenum optical fiber and communications raceways N N

Supported by open metal cable trays N N

Supported by solid bottom metal cable trays with solid metal

covers N N

In Risers

In vertical runs Y N

In metal raceways N N

In fireproof shafts Y Y

In plenum optical fiber and communications raceways N N

In riser optical fiber and communications raceways N N

In riser cable routing assemblies N N

In one- and two-family dwellings Y Y

Within Buildings in other than Air-Handling Spaces and Risers

General Y Y

Supported by cable trays N N

In distributing frames and cross connect arrays Y Y

In any raceway recognized in Chapter 3 N N

In plenum optical fiber and communications raceway N N

In riser optical fiber and communications raceway, and riser cable

routing assemblies N N

In general-purpose optical fiber and communications raceway,

What is the significance of this change?

Cable routing assemblies are used to support and organize large quantities of optical fiber, communications and data cables in high density applications such as installations of IT and communications equipment. They are fabricated from plastic and that could be problematical if materials with inadequate fire resistance were used. The fire tests and test criteria used for listing cable routing assemblies are identical to those used for optical fiber and communications raceways. A plenum grade cable routing assembly was not proposed out of deference to NFPA 90A which has the primary requirements for combustible is plenums. Proposals to cover plenum grade cable routing assemblies have been submitted for NFPA 90A and are currently being processed.

Restrictions on plenum cable in air ducts

Sections 770.113(B), 800.113(B), 820.113(B) and 830.113(B) prohibit the placing of cables in air ducts unless the cable “are directly associated with the air distribution system” and then the length of cable is limited to 4 ft.

What is the significance of these changes? The 2008 NEC permits

Types OFNP, OFCP, CMP, CATVP and BLP cables to be installed in “in ducts, plenums, and other spaces used for environmental air.” Section 4.3.4 of NFPA 90A-2009 states that “Wiring shall not be installed in air ducts” unless it is “directly associated with the air distribution system and does not exceed 1.22m (4 ft).” The changes in sections 770.113(B), 800.113(B), 820.113(B) and 830.113(B) were introduced in order to correlate with section 4.3.4.1 of NFPA 90A.

Restrictions on general-purpose cables in riser installations

Sections 770.154(B)(1), 800.154(B)(1), 820.154(B)91), 830.151(B)(1) and

830.154(B)(1) in the 2008 NEC require riser rated cables for vertical runs of more than one floor, permitting general-purpose cable for penetrations of one floor only. These sections also require that “Floor penetrations requiring” riser or plenum cables “shall contain only cables suitable for riser or plenum use.” In the 2011 NEC sections

770.113(D), 800.113(D), 820.113(D) and 830.113(D) require riser or plenum cables for vertical runs “penetrating one or more floors”. Application Tables 770.154(a),

800.154(a), 820.154(a) and 830.154(a) all show that general-purpose cables are not permitted in risers. The applications of communications wires and cables, and optical fiber cables are shown in the tables below. See Table 770.154(a) in the 2011 NEC for a complete table showing the Applications of Listed Optical Fiber Cables and Raceways, and Cable Routing Assemblies in Buildings. See Table 800.154(a) for the comparable table for communications. The applications of CATV cables and network-powered broadband cables are shown in Tables 820.154(a) and 830.154(a) respectively.

Applications of Optical Fiber Cables

Applications

Cable Type

OFNP, OFCP OFNR, OFCR OFNG, OFCG, OFN, OFC In Air Ducts In air ducts Y N N

In metal raceway that complies with 300.22(B) Y Y Y

In Other Spaces Used for Environmental Air (Ceiling Cavity, Raised Floor and Air-Handling Room Plenums)

In other spaces used for environmental air Y N N

In metal raceway that complies with 300.22(C) Y Y Y

In plenum optical fiber and communications

raceways Y N N

Supported by open metal cable trays Y N N

Supported by solid bottom metal cable trays

with solid metal covers Y Y Y

In Risers

In vertical runs Y Y N

In metal raceways Y Y Y

In fireproof shafts Y Y Y

In plenum optical fiber and communications

raceways Y Y N

In riser optical fiber and communications

raceways Y Y N

In riser cable routing assemblies Y Y N

In one- and two-family dwellings Y Y Y

Within Buildings in other than Air-Handling Spaces and Risers

General Y Y Y

Supported by cable trays Y Y Y

In distributing frames and cross connect arrays Y Y Y

In any raceway recognized in Chapter 3 Y Y Y

In plenum optical fiber and communications

raceway Y Y Y

In riser optical fiber and communications

raceway, and riser cable routing assemblies Y Y Y In general-purpose optical fiber and

communications raceway, and general-purpose cable routing assemblies

Applications of Communications Wires and Cables

Applications

Wire and Cable Type

CMP CMR CMG CM

CMX CMUC Hybrid power & communications

cables

In Air Ducts

In air ducts Y N N N N N

In metal raceway that complies with 300.22(B) Y Y Y Y N N

In Other Spaces Used for

Environmental Air (Ceiling Cavity, Raised Floor and Air-Handling Room Plenums)

In other spaces used for environmental air Y N N N N N

In metal raceway that complies with 300.22(C) Y Y Y Y N N

In plenum communications raceways Y N N N N N

Supported by open metal cable trays Y N N N N N

Supported by solid bottom metal cable trays with

solid metal covers Y Y Y Y N N

In Risers

In vertical runs Y Y N N N N

In metal raceways Y Y Y Y N N

In fireproof shafts Y Y Y Y N N

In plenum communications raceways Y Y N N N N

In riser communications raceways Y Y N N N N

In riser cable routing assemblies Y Y N N N N

In one- and two-family dwellings Y Y Y Y N Y

Within Buildings in Other Than Air-Handling Spaces

and Risers

General Y Y Y Y N N

In one- and two-family dwellings Y Y Y Y Y Y

In multifamily dwellings Y Y Y Y Y N

In nonconcealed spaces Y Y Y Y Y N

Supported by cable trays Y Y Y N N N

Under carpet N N N N Y N

In distributing frames and cross-connect arrays Y Y Y N N N

In any raceway recognized in Chapter 3 Y Y Y Y N N

In plenum communications raceways Y Y Y N N N

In riser communications raceways and riser

cable routing assemblies Y Y Y N N N

In general-purpose communications raceways

What is the significance of this change? Requiring riser cables (or plenum cables as

substitutes) is a simplification. With general-purpose cable no longer being permitted, it is no longer necessary to have separate floor penetrations, one for riser and plenum cables and the other for purpose cables. The change still permits general-purpose cables to be used in vertical runs in metal raceways or in fireproof shafts. Revision of Applications Sections

The text of applications sections of Articles 770, 800, 820 and 830 in the 2008 NEC (770.154, 800.154, 820.151 and 830.154) cover the applications of cables and raceways, and, notwithstanding the fact that the title of the sections is “applications”, contain numerous installation rules. In the 2011 NEC, installation rules have been moved out to the installation sections (770.113, 800.113, 820.113 and 830.113). The applications are now covered in tables (Tables 770.154(a), 800.154(a), 820.154(a) and 830.154(a)). A note at the bottom of each table explains that “An “N” in the table

indicates that the cable type is not permitted to be installed in the application. A “Y*” indicates that the cable is permitted to be installed in the application, “subject to the limitations” of the installation section. The NEC uses a “Y*” rather than a “Y” to

emphasize that permitted applications are subject to the limitations of installation rules. No asterisk is needed for the prohibited applications indicated by an “N” because the concept of “no” is simple.

Please view Tables 770.154(a), 800.154(a), 820.154(a) and 830.154(a) in the 2011 NEC.

What is the significance of these changes? The text in sections 770.154, 800.154,

820.151 and 830.154 in the 2008 NEC contains a mixture of applications and installation rules. Nearly all of the application statements are positive statements of where a cable, for example, is permitted to be used. Rarely do these sections state the prohibited applications, leaving to the user to infer the prohibited applications. For example, 800.154(C)(6) states that undercarpet cable is permitted to be installed under carpet, with no indication of any other permitted uses or prohibited uses. The new tables clearly indicate the prohibited applications with an “N”. See Table 800.154(a) or the above table to see the many prohibited applications of undercarpet cable.

Revision of Cable Installation Rules

While sections 770.113, 800.113 and 820.113 (Installation) in the 2008 NEC, are purported to cover installation of cables in their titles, they only required that listed cables be installed in buildings. In the 2011 NEC these sections have been greatly expanded to cover the installation of cables, wires, raceways, cable routing assemblies, and to also cover which cables are permitted to be installed in raceways, cable trays and routing assemblies in a variety of environments including air ducts, plenums, risers, general building spaces and in dwellings, one- ant two-family and multifamily dwellings. These sections are quite long and detailed. Please view sections 770.113, 800.113, and 820.113 in the 2008 and 2011 NEC.

What is the significance of these changes? The expansion of sections 770.113,

800.113, and 820.113 to provide detailed installation rules was done for two reasons, first, the removal of installation rules from the applications sections required that the installation rules be moved to the appropriate place, and second, expanding the detail of the installation rules greatly improved clarity.

Cable Ties and Mechanical Execution of Work

Sections 770.24, 800.24, 820.24 and 830.24 (Mechanical Execution of Work), all have a new informational note referencing NFPA 90A for testing discrete components installed in air ducts and “other spaces used for environmental air, (plenums)”.

What is the significance of this change? The mechanical execution of

work sections require that “cables shall be secured by hardware including straps, staples, cable ties, hangers, or similar fittings”. There are no requirements for listing these support hardware in the NEC, but NFPA 90A-2009 has heat release and smoke emissions requirements for “cable ties, and other discrete products” in sections 4.3.11.2.6.5 (ceiling cavity plenums) and

4.3.11.5.5.6 (raised floor plenums). Annex note A.4.3.11.2.6.5 provides guidance listing of testing of cable ties.

The new informational note refers to NFPA 90A-2009 for discrete combustible

components installed in 300.22(B) and 300.22(C) spaces. The spaces in 300.22(C) are other spaces used for environmental air that translate into ceiling cavity and raised floor plenums in NFPA 90A. The spaces in 300.22(B) translate into air ducts in NFPA 90A. There are no requirements for discrete combustible products in air ducts in NFPA 90A-2009.

Underground Communications Cables Entering Buildings

Section 800.47, which deals with separation requirements between communications cables and power cables, has a new statement that “310.10(C) shall not apply to communications wires and cables”. Section 310.10(C) requires that cables in a wet location be listed for use in wet locations.

What is the significance of this change? Under the provisions of section 90.3,

Chapter 8 is independent of Chapters 1 through 7; section 310.10(C) does not apply to Article 800 unless it is specifically referenced, which it is not. The statement that

310.10(C) does not apply was added for emphasis since some inspectors are nonetheless demanding wet rated telephone cable. The telephone cable that enters buildings underground is unlisted outside plant cable. It is designed to be buried in the

ARTICLE 840

Premises-Powered Broadband Communications

Systems

Article 840 is a new article in the 2011 NEC. Unlike Article 830, which covers Network-Powered Broadband Communications, Article 840 covers Premised-Network-Powered

Broadband Communications. The Scope states that these systems provide “voice, video, data, and interactive services through an optical network terminal”(ONT). The Article provides for the installation of the ONT, and just like Article 830, it refers to other articles for the output circuits of the ONT.

Output Circuit Applicable Article

Class 2 and Class 3 725

Fire alarm 760

Optical fiber 770

Communications 800

Cable TV 820

What is the significance of this change? Article 840 was created to accommodate

FiOS (fiber optic service), which brings an optical fiber to the customer premises and derives telephone, television and internet service through an ONT. Creation of a new article was necessary because the scope of Article 770, Optical Fiber Cables and Raceways, only covers “the installation of optical fiber cables, raceways, and cable routing assemblies”, consequently the installation requirements for the ONT could not be inserted into Article 770. Use of Article 800 was a possibility, but Article 800 defers to Article 770 for optical fiber cable installation.

ARTICLE 725

Class 1, Class 2, and Class 3 Remote-Control,

Signaling, and Power-Limited Circuits

&

ARTICLE 760

Fire Alarm Systems

Raceways

Sections 725.3(H) and 760.3(H) in the 2011 NEC require raceways exposed to different temperatures to comply with 300.7(A). Section 300.7(A) requires that raceways that are subjected to different temperatures, as for example raceways passing through a

refrigerated area of a building, be sealed to prevent the circulation of warm air and the subsequent condensation.

Sections 725.3(J) and 760.3(J) require bushings to be installed on the ends of raceways to protect them from abrasion.

Section 760.3(J) requires fire alarm cables installed in raceways to comply with raceway fill requirements.

What is the significance of these changes? Articles 725 and 760 exempt

themselves from the provisions of Article 300 Wiring Methods except from those sections that are specifically referenced. The result of these new requirements is that 300.7(A) which deals with raceway sealing, and 300.15(C) which deals with abrasion protection of cables emerging from raceway, now apply to data (class 2) and fire alarm cables. They already apply to communications and optical fiber cables because 770.110 and 800.110 require that raceways recognized in Chapter 3 be installed in accordance with Chapter 3.

Now that raceway fill requirements to fire alarm cables, fire alarm cables have a

requirement that is not applied to data cables, optical fiber cables and communications cables. Section 760.154(D) permits communications cables to substitute for power-limited fire alarm cables, but the wiring rules for fire alarm cables still apply.

Consequently, communications cables that are being used for fire alarm circuits are subject to the raceway fill requirements while the same cables installed in raceway for communications purposes are not subject to raceway fill requirements.

Prepared by Stanley Kaufman, Ph.D. CableSafe, Inc.

Member of NEC Panels 12 and 16

November 4, 2010

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